January 2005

THE SELF-ESTEEM MYTHS ■ IMMUNITY’S EARLY-WARNING SYSTEM

Capturing Life under the Lens

JANUARY 2005 WWW.SCIAM.COM

Unbreakable Quantum Encryption Has Arrived

Reanimating a Killer to Stop Flu Pandemics

A Cosmic Midlife Crisis

Computers That Learn Your Priorities

LIFE SCIENCES 38 Immunity’s Early-Warning System BY LUKE A. J. O’NEILL The body’s ﬁ rst line of defense against invading microbes may be the key to better ways of battling infections and inﬂ ammatory disease.

ASTROPHYSICS 46 The Midlife Crisis of the Cosmos BY AMY J. BARGER The cosmic ﬁ reworks of the early universe have given way to quieter, more mature galaxies that still build stars and black holes with surprising efﬁ ciency.

INFORMATION SCIENCE 54 Considerate Computing BY W. WAYT GIBBS Feeling overloaded by intrusive digital technology? New attentive interfaces for computers, phones and cars will understand your priorities.

BIOTECHNOLOGY 62 Capturing a Killer Flu Virus BY JEFFERY K. TAUBENBERGER, ANN H. REID AND THOMAS G. FANNING Researchers have resurrected the deadliest ﬂ u in history to learn why it killed millions and how to prevent the next pandemic.

SCIENCE IN PICTURES 72 Eye of the Beholder TEXT BY EMILY HARRISON Gorgeous entries in the Nikon Small World photomicroscopy competition reveal minute biological beauties that elude unaided vision. What is it? INNOVATION See page 6 78 Best-Kept Secrets BY GARY STIX Quantum cryptography, long touted as a theoretical ﬁ x for data security problems, ﬁ nally takes shape in commercial products.

PSYCHOLOGY 84 Exploding the Self-Esteem Myth BY ROY F. BAUMEISTER, JENNIFER D. CAMPBELL, JOACHIM I. KRUEGER AND KATHLEEN D. VOHS Boosting students’ self-esteem has become a national preoccupation— but it does little to improve grades or discourage bad behavior. www.sciam.com SCIENTIFIC AMERICAN 5 COPYRIGHT 2004 SCIENTIFIC AMERICAN, INC. SCIENTIFIC AMERICAN Volume 292 Number 1 departments 8 SA Perspectives Catching the ﬂ u—the right way. 10 How to Contact Us 10 On the Web 20 102 12 Letters 16 50, 100 & 150 Years Ago 18 News Scan 36 Insights ■ Eliminating polio: maybe this year. Hans Moravec of Carnegie Mellon University ■ Robots might fail Hubble. aspires for robots to be humanity’s successors. ■ A more sound way to count salmon. 92 Working Knowledge ■ Supersolid helium 4. The key to keyless entry. ■ Big mysteries on Titan’s surface. ■ Snakeheads are staying put. 94 Reviews ■ Data Points: Particulates all around. Collapse considers the choices that kill societies. ■ By the Numbers: The nurse shortage. Also, a shelf of new books on Albert Einstein celebrates the new Year of Physics.

Roboticist Hans Moravec 36 columns 34 Skeptic BY MICHAEL SHERMER A hit fi lm justifi es hogwash with quantum mechanics. 102 Anti Gravity BY STEVE MIRSKY Why 12 ferrets watched The Matrix. 104 Ask the Experts How do hackers infi ltrate computers? Why do traffi c jams materialize for no reason?

WHAT IS IT? Hamster kidney cells ﬂ uoresce in culture. Photograph on page 5: Albert Tousson, University of Alabama at Birmingham, courtesy of Nikon Instruments.

Cover image by Kenn Brown; photograph at left by Scott Goldsmith.

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A global influenza pandemic is closer than at any fected with this season’s circulating human fl u strain, time in a generation. Klaus Stöhr, head of fl u surveil- whose healthy-looking pet duckling then gives her lance at the World Health Organization, made that H5N1. In the past year more than 40 people in Thai- uncharacteristically dramatic declaration back in land and Vietnam have already contracted the avian November, before convening an emergency summit virus, and more than 30 of them have died from it. of vaccine manufacturers and national health agency Beginning on page 62 of this issue, Jeffery K. offi cials. The reason was the escalating avian infl u- Taubenberger and his colleagues describe their resur- enza crisis in 10 Asian countries, which poses a direct rection, literally from the grave, of the virus that killed threat to human health. upward of 40 million people in 1918–1919. And they Because the avian virus, known offer a chilling conclusion about its origin. Although as H5N1, is lethal in chickens, iden- certain genes in that virus may have come from a bird tifying local outbreaks was easy. strain, the genes look as though they spent signifi cant Stöhr was alarmed by evidence that time evolving in yet another animal before the virus the virus is also widespread in the emerged among humans. This unknown source of the region’s domestic ducks, which show 1918 pandemic might even have been a type of bird no symptoms. With asymptomatic or animal that we don’t recognize as a fl u carrier. ducks waddling through barnyards, Systematic surveillance for infl uenza is currently backyards and kitchens shedding limited to humans, chickens, swine and horses, with virus, hope of stamping out this wild waterfowl and shore birds tested less regularly. largest avian fl u outbreak in history But few of these samples are closely analyzed, and has dimmed. And the likelihood of scientists do not know the dynamics or true scope of SUSPECT DUCKLING eyed human exposure to the virus, which the infl uenza ecosystem. The National Institutes of by Chinese health workers. could spark a pandemic, has in- Health just announced plans to sequence the genomes creased. “We know the recipe, and of existing fl u samples. In addition, the Armed Forc- all the ingredients are there,” Stöhr said. es Institute of Pathology, the Centers for Disease Flu pandemics are caused by viruses with surface Control and Prevention, and several partners want to proteins unfamiliar to human immune systems. In create a high-capacity laboratory network dedicated the pandemic strains of 1957 and 1968, such proteins to expanding fl u surveillance capability and molecu- came from fl u viruses that previously infected only lar analysis of infl uenza viruses. Studying how they birds. That was possible because fl u is a promiscuous evolve and move through human and animal popula- gene swapper. If an avian strain meets a fl u strain tions might identify new fl u reservoirs and enable the adapted to spreading among mammals, their proge- emergence of new strains to be predicted. ny may possess the deadly combination of protein Start-up costs would equal the price of the two mil- novelty and easy transmissibility between humans. lion emergency H5N1 vaccine doses the Department The exchange can happen inside animal hosts suscep- of Health and Human Services ordered in September. tible to both avian and human fl u strains, such as The money would be well spent for an ounce of pre-

pigs. Or it might happen inside a farmer’s child in- vention against future ﬂ u pandemics. PHOTOS/REUTERS/CORBIS CHINA

THE EDITORS [email protected]

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EDITOR IN CHIEF: John Rennie THE RESPONSES to the September single-topic issue on Al- EXECUTIVE EDITOR: Mariette DiChristina bert Einstein were philosophical, thoughtful, contentious and MANAGING EDITOR: Ricki L. Rusting NEWS EDITOR: Philip M. Yam abundant. Comments about the SA Perspectives, “Einstein = SPECIAL PROJECTS EDITOR: Gary Stix Man of Conscience2,” suggest that E = mc2 could also stand SENIOR EDITOR: Michelle Press 2 SENIOR WRITER: W. Wayt Gibbs for Einstein commentaries = much controversy . EDITORS: Mark Alpert, Steven Ashley, Less disputatious were recollections of Einstein the per- Graham P. Collins, Steve Mirsky, George Musser, Christine Soares son. Ralph Townsend of Oxford, England, related an encounter CONTRIBUTING EDITORS: Mark Fischetti, with the great physicist that shows it is the little things that Marguerite Holloway, Philip E. Ross, Michael Shermer, Sarah Simpson, Carol Ezzell Webb demonstrate character: A friend of his who worked in Princeton,

EDITORIAL DIRECTOR, ONLINE: Kate Wong N.J., “had a young daughter who had difﬁ culty understanding ASSOCIATE EDITOR, ONLINE: Sarah Graham math problems, which he would try to elucidate, but with little

ART DIRECTOR: Edward Bell success. When she asked him, ‘Who could explain this to me?’ SENIOR ASSOCIATE ART DIRECTOR: Jana Brenning he replied, ‘I’m afraid it would take Einstein.’ The resourceful child found Einstein’s address and, ASSOCIATE ART DIRECTOR: Mark Clemens ASSISTANT ART DIRECTOR: Johnny Johnson on the way to school, visited him, saying, ‘My father says that only Einstein could explain this PHOTOGRAPHY EDITOR: Emily Harrison problem.’ She was invited in, and Einstein enlightened her. When her parents discovered, after PRODUCTION EDITOR: Richard Hunt she had become habitually late for school, that these meetings had become routine, they apol- COPY DIRECTOR: Maria-Christina Keller COPY CHIEF: Molly K. Frances ogized to the Einsteins, who replied that they enjoyed seeing her and continued to let her visit.” COPY AND RESEARCH: Daniel C. Schlenoff, Following are more comments on this physics revolutionary, who by setting the universal Michael Battaglia, Smitha Alampur, Sara Beardsley speed limit diminished the limits on our understanding of the universe. EDITORIAL ADMINISTRATOR: Jacob Lasky SENIOR SECRETARY: Maya Harty ASSOCIATE PUBLISHER, PRODUCTION: William Sherman 2 murdered by Arab terrorists. They have MANUFACTURING MANAGER: Janet Cermak EINSTEIN = MAN OF CONSCIENCE ADVERTISING PRODUCTION MANAGER: Carl Cherebin You indicate that Albert Einstein [SA always peacefully coexisted with the PREPRESS AND QUALITY MANAGER: Silvia Di Placido Perspectives] would have found causes Arab citizens of Israel, who enjoy more PRINT PRODUCTION MANAGER: Georgina Franco PRODUCTION MANAGER: Christina Hippeli for moral outrage today, giving as an ex- civil liberties than in any Arab country. CUSTOM PUBLISHING MANAGER: Madelyn Keyes-Milch ample that “though a Zionist, he had Yes, I think Einstein would be out- ASSOCIATE PUBLISHER/VICE PRESIDENT, CIRCULATION: always insisted that Jews must live peace- raged. He never forgave Germany for Lorraine Leib Terlecki CIRCULATION DIRECTOR: Katherine Corvino ably with Arabs.” But with whom would what it had done to the Jews of Europe, FULFILLMENT AND DISTRIBUTION MANAGER: Rosa Davis he be outraged? and I don’t think he would forgive Arab VICE PRESIDENT AND PUBLISHER: Bruce Brandfon The Israeli Jews wanted nothing more leaders for what they have done to the WESTERN SALES MANAGER: Debra Silver SALES DEVELOPMENT MANAGER: David Tirpack than to live peaceably with Arabs when Jews of Israel. WESTERN SALES DEVELOPMENT MANAGER: they accepted a small fraction of the orig- Steven Weinberg Valerie Bantner SALES REPRESENTATIVES: Stephen Dudley, inal Palestine Mandate in the 1948 U.N. Department of Physics Hunter Millington, Stan Schmidt partition, but they were attacked by all University of Texas at Austin ASSOCIATE PUBLISHER, STRATEGIC PLANNING: neighboring Arab states. After surviving Laura Salant PROMOTION MANAGER: Diane Schube this, they wanted to live peaceably with I applaud your celebration of Einstein. RESEARCH MANAGER: Aida Dadurian Arabs, but they were continually ha- He was truly a genius of the ﬁ rst order. PROMOTION DESIGN MANAGER: Nancy Mongelli GENERAL MANAGER: Michael Florek rassed by boycotts and border raids and Unfortunately, I feel it was diminished BUSINESS MANAGER: Marie Maher excluded from using the Suez Canal. by your comments in SA Perspectives. MANAGER, ADVERTISING ACCOUNTING AND COORDINATION: Constance Holmes In 1967 they were again attacked by The editors “speculate that Einstein ... DIRECTOR, SPECIAL PROJECTS: Barth David Schwartz Arab states, even though Israel then held would have opposed his adoptive na- MANAGING DIRECTOR, ONLINE: Mina C. Lux no part of the West Bank or Gaza Strip. tion’s foray into Iraq.” I disagree. First, OPERATIONS MANAGER, ONLINE: Vincent Ma After surviving this, they wanted to live how could you divine the opinion of a SALES REPRESENTATIVE, ONLINE: Gary Bronson WEB DESIGN MANAGER: Ryan Reid peaceably with Arabs, though now inside man 50 years dead, even if he was well defensible borders. Since then, Israeli known for opinions on war? He was also DIRECTOR, ANCILLARY PRODUCTS: Diane McGarvey PERMISSIONS MANAGER: Linda Hertz Jews have made many offers to withdraw outspoken against genocide during the MANAGER OF CUSTOM PUBLISHING: Jeremy A. Abbate from most of Gaza and the West Bank Holocaust. Saddam didn’t kill as many CHAIRMAN EMERITUS: John J. Hanley and live peaceably with their Arab inhab- people as Hitler, but he is a mass mur- CHAIRMAN: John Sargent PRESIDENT AND CHIEF EXECUTIVE OFFICER: itants, but these offers have always been derer. May this have led to a more nu- Gretchen G. Teichgraeber refused. They were attacked again by anced position by Einstein? VICE PRESIDENT AND MANAGING DIRECTOR, Arab armies in 1973, coming close to de- If you feel the war was wrong, that’s INTERNATIONAL: Dean Sanderson VICE PRESIDENT: Frances Newburg feat, and their citizens continue to be your privilege. But don’t attach your

12 SCIENTIFIC AMERICAN JANUARY 2005 COPYRIGHT 2004 SCIENTIFIC AMERICAN, INC. Letters opinion as a postscript to humankind’s tury, and proofs today still use the forms Reading the string theory article greatest thinker. he established. As for Archimedes, he is brought to mind some questions con- Kris Stone one of the towering fi gures in mathemat- cerning the formation of bubble uni- Fresno, Calif. ics and engineering; his work on statics verses: What will happen if a new bub- and hydrostatics is the foundation of ble, with different physical laws, starts THE EDITORS REPLY: We think that Einstein both. Whereas some of his best work to form in a neighboring galaxy? Will might have found reasons for outrage on both had little impact because it was so far we see it? What will it look like? Will it sides of the Arab-Israeli confl ict; poor phras- ahead of its time, other writings of his engulf us? ing made it seem we were siding against Is- infl uenced scientists for centuries. Karl Dahlke rael when we were not. Some readers seem No historian of science should over- Troy, Mich. unclear about the meaning of “speculate.” look either of these men just because They are welcome to disagree with our guess. they lived so long ago. BOUSSO AND POLCHINSKI REPLY: The for- Whatever Einstein’s views on these topics Gillian Bradshaw mation of a new bubble releases an enor- would have been, our point was that history Coventry, England mous amount of energy, which goes into suggests he would have been outspoken. growing and accelerating the bubble wall. LIGHTMAN REPLIES: Bradshaw writes that I For this reason, the wall moves nearly at the Regarding Einstein, you write: “It’s only had claimed that no person before Newton speed of light. Barely a moment after we fi rst natural that a man who showed how to had the scientifi c accomplishments of Ein- catch sight of the bubble, it will already have bend space and stretch time should be- stein. I did not state that claim in categorical engulfed us. come a titan of science. Yet Einstein also language but only suggested it, using the This is a catastrophic event. The parti- attained a wider renown than many of word “might.” I agree that Archimedes and cles we know will decay, along with all mem- his equally brilliant peers in physics.... Euclid were powerful thinkers. It would be ory devices made from them. Surely the reason is that the public had hard for anyone to argue convincingly that The good news is that this apocalypse is feelings for him beyond admiration.” Einstein’s accomplishments were more or unlikely to occur soon, even by astronomical You suggest that there were many less than their achievements. What is impor- standards. “Einsteins,” but only one acquired the tant is that we must reach through the cen- exceptional admiration and renown that turies for any comparison to Einstein. ERRATA On page 48 of the timeline in “The we all abundantly bestow on him. Patent Clerk’s Legacy,” by Gary Stix, the Closer is the description that should caption for the year 1931 misidentifi ed be added to the editors’ words the man standing to the right of Albert above: ... and that he discovered Einstein as Edwin Hubble. He is Robert E = mc². Millikan. Alex Blum The fi rst sentence of the letter from Bar-Ilan University William Donelson of Wimbledon, London

Ramat-Gan, Israel was incorrectly edited to read, “Where- ) as emissions of carbon monoxide will right ALBERT AND ISAAC drop in a hydrogen economy....” The Alan Lightman in “Einstein and writer stated that emissions of carbon Newton: Genius Compared,” dioxide would drop. We very much re- makes the provocative statement EINSTEIN AND NEWTON: On whose shoulders do they stand? gret the error. that nobody before Newton can be In “Everyday Einstein,” by Philip compared with Einstein. UNTANGLING STRING THEORY Yam, it was stated that the gravitational pull ( BETTMANN/CORBIS ); What about Euclid and Archimedes? As a nonscientist, the very idea of string on GPS satellites is one quarter the attrac- left The indispensable achievements of sci- theory makes my heart sink, and articles tion they would experience on Earth’s sur- entists of antiquity are often overlooked. about it usually leave me more confused face. The statement should have referred Although Euclid was a mathematician, than before I started. So congratulations explicitly to gravitational potential, which his work comprises one of the ﬁ rst at- to Raphael Bousso and Joseph Polchin- varies linearly with the inverse of the dis- tempts to describe the fundamental prin- ski for writing “The String Theory tance (and is used to calculate time-dilation ciples of nature through mathematics, Landscape,” a clear and enlightening corrections). In a GPS orbit, gravitational and every physicist owes him a debt. piece on this abstruse topic. force—which varies with the inverse square Enormously influential, Euclid’s Ele- Richard Tagart of the distance—is 1/16 of that on the

ments was a standard into the 19th cen- Antwerp, Belgium ground. ( COLLECTION/CORBIS HULTON-DEUTSCH

Personality Clash ■ War Worries ■ Heavenly Revolutions

JANUARY 1955 Sabena Airlines recently demonstrated thropist that science had made modern UNSOCIAL SCIENTISTS—“Are the social that a helicopter cruising at only 75 warfare so shocking and terrifying as to traits that characterize so many scientists miles per hour could get passengers render its continuance impossible, fades to be regarded as defects of personality from downtown Brussels to London pitifully away in the presence of that aw- bordering on the abnormal? The answer more quickly than a 250-mile-per-hour ful panorama at Port Arthur, where the is no. Mental or emotional breakdowns airliner whose passengers had to taxi to bodies of brave men lie rotting by the were no more common among scientists and from the airports.” thousand on the snow-covered slopes of than among nonscientists in our gifted the fortifi cations, truce for burial being sample of the population. At any rate, in JANUARY 1905 deemed incompatible with the exigencies our gifted group the physical scientists HORSE NERVES—“A resident of Canada of successful warfare.” and engineers are at the opposite pole proposes to humor the skittish horse by from the businessmen and lawyers in attaching life-size dummy horses in front JANUARY 1855 abilities, in occupational interests and in of automobiles [see illustration], so that COMETARY ORBITS—“The orbits of all social behavior. These basic personality they will present the appearance of horse- the planets, and probably of nearly ev- differences may well account for much of drawn vehicles. Aside from its offi ce of de- ery comet, are ellipses, having the sun the current friction between scientists and ceiving timid and high-strung horses, the in one of their foci. No attracting body the government offi cials who are respon- head of the horse carries a search light for can exist in the upper focus of the orbit sible for their security clearances and for use at night [see inset in illustration], and of any comet which is known to be pe- the restrictions imposed upon them.” in its mouth the animal carries an auto- riodical, it being impossible for a body mobile horn.” to remain motionless at such a point. DOWN WITH LOVE—“In a study of 1,297 The nearest fi xed star whose distance telephone operators, researchers found RUSSO-JAPANESE WAR—“Most sincerely has been ascertained, Alpha Centauri, that the typical ill operator was a mar- does the Scientifi c American regret the is more than two hundred thousand ra- ried woman, widow or divorcee who had fact, as disclosed by the present war, that dii of the earth’s orbit from the sun. It hoped to be a housewife and mother. De- the refi nements of science, instead of miti- requires light, moving continually at the prived of her husband’s support by death, gating, as we had many of us fondly hoped rate of 192,000 miles per second, above 1 desertion or incompatibility, she had they would, the horrors of war, have mul- 3 /4 years to traverse this interval. How been forced to continue working, often tiplied them. The dream of the philan- long then would it require a comet to while rearing small children. The complete the double tour? That healthiest operators, on the other comets do not reach our system hand, tended to be single women from the regions of the fixed with little drive toward marriage stars is quite evident.” and whose ambitions did not go much beyond the modest satisfac- BAD HAIR ROOM—“Hair used in tions of their jobs.” plaster for new houses is, very frequently, so dirty as to emit HELICOPTERS—“The helicop- unpleasant effluvia, which is ter’s versatility and uses are quite sickening, and calculated formidable and growing, but to keep a room unhealthy for none of them yet adds up to years afterwards. Hair used mass transportation. The heli- for mixing in mortar should be copter’s future assuredly rests thoroughly washed—re-washed, on its unique property of being and dried, and thus deprived of able to take off from the center the putrid matter that often ad- of a crowded city, overleap the heres to it. The lime in mortar traffic jams of surface travel is not suffi cient to cleanse the and land in an equally crowded hair. It will generate an unpleas- center. It can do this with good DUMMY HORSE for calming real horses, 1905 ant sickly effl uvia whenever the speed and superlative safety. room is heated.”

he celebration started January 15, consign polio to the same fate as smallpox, 2004, when health ministers of the last declared ofﬁ cially banished in 1980. six countries where the poliovirus still Unfortunately, polio has proved to be a T — circulated Afghanistan, India, Pakistan, much trickier disease, and the world is a dif- Egypt, Nigeria and Niger—gathered in Ge- ferent place than it was in the 1970s. Rather neva to commence a very public countdown. than having been eliminated, polio is now After 15 years and some $3 billion, the present in 10 countries. The polio program Global Polio Eradication Initiative was go- has succeeded in many difﬁ cult areas, says ing to halt all transmission of the “wild” University of Pittsburgh professor D. A. Hen- virus by the end of the year and thereafter derson, who led the smallpox eradication program and guided polio eradication in the Americas. “But at this time they’re running into some very heavy weather,” he warns. Polio’s perfect storm started in the summer of 2003 in northern Nigeria. In the Kano state, politicians and clerics claimed that the polio vaccine was a “Western” ploy, tainted with HIV or with hormones meant to render Muslim women infertile. The resulting resistance to the eradication program led to immunizations being suspended for 11 months. By the summer of 2004, outbreaks in Nigeria had spread to 10 surrounding nations that had been polio-free for years, leaving nearly 700 children paralyzed and rees- tablishing polio in four countries. A massive mop-up campaign began in October, involving one million volunteers in 23 African countries attempting to vaccinate 80 million children by year’s end. The unex- MOBILE IMMUNIZATION TEAM in northern Nigeria carries insulated boxes of oral polio vaccine pected setback cost the cash-strapped eradi- during a mass-vaccination campaign in early October.

cation program an additional $100 million. UNICEF/HQ04-0733/MUDI YAHAYA

18 SCIENTIFIC AMERICAN JANUARY 2005 COPYRIGHT 2004 SCIENTIFIC AMERICAN, INC. news a virulent wild strain of the poliovirus.) WILD POLIO was exported to 10 polio-free countries SCAN from Nigeria in 2004. Meeting an end-of-2005 target in Africa will require a “heroic effort,” according to The goal for ending wild-virus transmission Henderson. The 13 African countries where worldwide has now slipped to the end outbreaks occurred last year cover an area of 2005. bigger than the 48 contiguous states and “It’s certainly biologically feasible” have a population of some 300 million peo- to meet the new target date, says Da- ple. Because polio only causes a detectable vid L. Heymann of the World “acute fl accid paralysis” in one of every 200 Health Organization. Since victims, it is much harder to ferret out than Heymann took over the polio smallpox, Henderson adds, and 800 docu- Nigeria program in mid-2003, the vet- mented cases in Africa mean that 160,000 eran epidemiologist has observed people were probably infected. Endemic countries that political will is the real wild India, Pakistan and Afghanistan are in Polio imported, card [see “A Strategy of Con- far better shape. By early November, India transmission reestablished tainment,” by Christine Soares; had detected only 81 cases. According to Polio imported Scientifi c American, March Heymann, all three Asian countries should Case or outbreak 2004]. So he has spent much of “fi nish up” efforts to halt wild-virus trans- his tenure traveling to drum up po- mission early in 2005. Doing the same in Af- VEXING litical support for polio eradication. rica by the end of the year is essential, he says: VACCINE One of Heymann’s fi rst big accomplish- “If countries don’t do it now, it won’t happen. ments was gaining an endorsement from the This is the best chance we’ll ever have.” Wild poliovirus is present in India, Pakistan, Afghanistan, Nigeria, Organization of the Islamic Conference The polio program’s tribulations may al- Niger, Egypt, Ivory Coast, Burkina (OIC), a confederation of 56 Muslim na- ready have dampened enthusiasm for the Faso, Chad and Sudan. These tions. Polio has hit the group hard: fi ve of the concept of total disease eradication. Measles nations hope to eliminate the six original endemic countries and two was supposed to be next, but measles fi ght- disease by the end of 2005. The where wild virus was reestablished are mem- ers are only “talking about mortality reduc- World Health Organization will wait three years before certifying that bers. Malaysia and the United Arab Emir- tion and catch-up” these days, Heymann wild virus is no longer circulating ates, both in the OIC, each made $1-million remarks. in the world. Then the agency contributions to the eradication program “There’s been an undue emphasis on the faces another hurdle: banning last year. The organization’s support also idea that we’re going to eradicate things,” further use of the oral polio softened opposition in Nigeria. By last Henderson says, despite his own successes vaccine (OPV) and destroying any remaining stockpiles. The live spring, Kano offi cials agreed to resume vac- against smallpox and polio. Noting tremen- virus in OPV can mutate back into cinations but made a show of purchasing dous progress in controlling childhood dis- pathogenic form, and at least four the vaccine from Muslim Indonesia, and eases, such as neonatal tetanus and rubella, polio outbreaks have been sending it to India to be safety-tested. (Iron- Henderson thinks that if nothing else, “the attributed to the vaccine itself. The ically, India, where polio is still endemic, has polio program has served to show countries Global Polio Eradication Initiative does not want to eradicate yet to resolve two past incidents of locally what could be done with large-scale immu- polio only to combat manufactured vaccine being contaminat- nization, when you mobilize a whole com-

vaccine-derived outbreaks. ed—either accidentally or intentionally—by munity to act.” MORGENSTEIN CARLI

SPACE A Bad Fix for Hubble? ROBOTIC REPAIR MAY BE RISKIER THAN FIRST THOUGHT BY STEVEN ASHLEY

he decision to repair the Hubble Space years with upgraded sensors. And all the ex- Telescope with robotics technology perience gained by using teleoperated ma- T seemed a natural given the safety con- nipulators would form the basis of future cerns raised by the crash of the space shuttle semiautonomous servicing operations in Columbia in 2003. That way the observa- space. Now, however, independent analyses tory prized by scientists and admired by the have cast fresh doubts on whether a robotic public could function for at least ﬁ ve more mission can reliably save Hubble.

20 SCIENTIFIC AMERICAN JANUARY 2005 COPYRIGHT 2004 SCIENTIFIC AMERICAN, INC. According to the original scheme, space- wise diffi cult-to-install gyroscopes inside news walking astronauts would have replaced the wide-fi eld camera, which is to be at- SCAN failing batteries, gyroscopes and fi ne-guid- tached to the internal telescope structure ance sensors. In addition, new scientifi c in- from the outside. Robotic repair “will be struments—including a wide-fi eld camera very slow—maybe 10 times slower than by and a spectrograph—would have boosted the astronauts, but it’s defi nitely doable,” Hubble’s observational ability by a factor of Burch says. 10 or more. A National Research Council commit- But after the Columbia disaster, NASA tee, led by Louis J. Lanzerotti of Bell Labo- scaled back its shuttle plans. Unlike fl ights ratories and the New Jersey Institute of to the International Space Station, a mission Technology, does not seem so sure, howev- to Hubble provides no repair depot and safe er. In an interim study report, the panel stat- haven for the shuttle and its crew in an ed: “The proposed Hubble robotic servicing emergency. In its stead, the space agency mission involves a level of complexity, so- contemplated unmanned rescue efforts. phistication, and technology maturity that Various technical obstacles confront an requires signifi cant development, integra- unmanned mission, ex- tion, and demonstration plains Preston Burch, pro- to reach flight readi- gram manager for the ness.” The committee NASA Goddard Space warned that the pro- Flight Center. One, the posed unmanned mis- self-guided orbital repair sion is essentially an ex- module will have to “ren- periment that is expect- dezvous and soft-dock” ed to accomplish diffi cult with Hubble without any real-world objectives assistance from the tele- and that relying on un- scope or ground staff. tested procedures is (Previous automated risky. It urged NASA to dockings have been little “take no actions that more than “controlled would preclude a space crashes.”) He notes that shuttle servicing mis- WHY NOT these advanced maneu- sion.” Not exactly a vers will be demonstrated ringing endorsement. LET HUBBLE DIE? in the near future by a trio The Aerospace Cor- A refurbished Hubble Space of NASA and Defense De- poration, a nonprofit Telescope has much yet to partment spacecraft. MANHANDLED: The Hubble Space private research, devel- contribute. The new instruments Telescope is brought into the space Two, the robot arms will opment and advisory that are to be installed, including shuttle’s cargo bay by its teleoperated the Wide Field Camera 3 and the have to unfasten several organization headquar- arm during the 1999 servicing mission. Cosmic Origins Spectrograph, “are types of latches, connect tered in El Segundo, Ca- at least an order of magnitude cables, and exchange a variety of fragile de- lif., is also skeptical. According to those more powerful than their vices, often in tight spaces. The dual robot- who have seen its confi dential assessment, predecessors in orbit,” declares ic manipulator arms, fi tted with tiny video the study concludes that the probability of astronomer Garth Illingworth of the University of California’s cameras and precision positioning sensors, success of a robotic mission attempting only Lick Observatory. must accomplish the work mostly autono- minimal goals (extending Hubble’s life) is mously with only limited supervision from 58 percent. Worse, the odds are one in three “If serviced, Hubble could do earthbound operators. (Because of the dis- for a more ambitious automated effort to unique and pioneering tance and other factors, communications install a “deorbit module” (a rocket motor observations on nearly everything from planets circling face a delay of a few seconds.) to control reentry) and to upgrade scientifi c nearby stars to the most distant Nevertheless, detailed analysis and lab- instruments. These odds are less than those and enigmatic gamma-ray burst oratory tests of key procedures with full- of a manned shuttle mission, which offers a objects to the unknown dark scale facsimile hardware give the Goddard 63 percent chance of success, say sources energy,” states John Bahcall of staff and their contractors a good deal of who asked to remain unidentifi ed. the Institute for Advanced Study I

C in Princeton, N.J. “If successful, confidence. Clever workarounds should Then there is the issue of cost. Burch the best days of Hubble are in the ease matters considerably as well. Engi- says NASA’s “conservative” estimate for a future because we have learned

NASA/STS neers, for example, would place the other- robotic mission is $1.3 billion, whereas in- how to use it so well.”

www.sciam.com SCIENTIFIC AMERICAN 21 COPYRIGHT 2004 SCIENTIFIC AMERICAN, INC. formants indicate that the Aerospace tic because of the long delay until the analysis pegs it at about $2 billion. The spacecraft could be constructed. NASA latter also reportedly set the price tag of has slated the launch of Hubble’s re- a shuttle servicing ﬂ ight at around the placement, the James Webb Space Tele- same amount. scope, for 2011. Finally, the estimates of the time nec- Given the pessimism surrounding essary to build the required technologies robotic rescue, NASA may have to opt are said to differ. The Goddard team for what many scientists and astronauts thinks they can be ready by late 2007, favor—a return to “plan A.” Servicing whereas the Aerospace group estimates Hubble with humans is uncertain, but completion in 2010—a severe hitch be- that seems to be a risk astronauts are cause Hubble’s current main batteries willing to take. “Frankly, we use robot- are likely to fail by 2009, placing the ob- ics whenever we can,” says Apollo as- servatory permanently out of action. tronaut Walter Cunningham, who As an alternative to robotic repair, drafted a petition, endorsed by 26 for- the Aerospace evaluation considered mer astronauts, supporting the restora- orbiting a new vehicle containing the tion of the shuttle effort. “But very few improved observational instruments. people feel that robotics are sophisti- Many observers, however, deem this cated enough to do what the shuttle ser- $2-billion “rehosting” option unrealis- vicing mission would accomplish.”

FISHERIES Sound Findings SONAR OFFERS A WAY TO COUNT SALMON ACCURATELY BY DAVID KOSUB

he debate is as fierce and peren- tosis (the size of the pulse’s top half nial as the surf pounding the Alas- relative to that of the bottom half). Sci- T ka coastline. On one side, commercial and sports fi shermen complain that calculated fi shing quotas do not match the number of fi sh actually in the water. On the other, conservation au- thorities worry that overfi shing will de- plete the sockeye and chinook salmon stocks plying the Pacifi c Northwest waters. New techniques using existing acoustic sonar equipment may help both sides by determining how many salmon are in the water as well as dis- tinguishing one species from the other. And that could make counting and catching them a lot easier. In sonar setups such as fi sh fi nders, pulses of sound bounce off the water’s bottom—and off any creatures that happen to swim by. Typically devices record the strength of the return echo, SALMON SPOTTING relied on a collection of four thereby indicating the rough numbers sonar transducers mounted on a plate; each of fi sh and their sizes. one generates a particular frequency (70, 120, 200 and 400 kilohertz, from the largest Echo pulses have other characteris- to the smallest transducer).

tics, too, such as width, shape and kur- BURWEN DEBBY OF COURTESY

22 SCIENTIFIC AMERICAN JANUARY 2005 COPYRIGHT 2004 SCIENTIFIC AMERICAN, INC. entists have largely ignored these features, because they believed that background noises obscure whatever information they may contain. Some investigators decided to challenge that belief. This past summer researchers at Fisheries and Oceans Can- ada and the U.S. National Marine Fish- eries Service in Alaska mounted four acoustic transducers on a metal plate beside Alaska’s Kenai River. The transducers then fi red simultaneous sound waves, each at different frequencies, at approximately 40 chinook and sockeye salmon tethered to the river bottom with fi shing line. “We’ve learned,” says physicist Tim Mulligan with Fisheries and Oceans Canada, “that, indeed, the fi sh’s shape” and its positioning measurably alter the return echo, a fi nding “that wasn’t really documented until now.” For instance, the degree to which a salmon’s head and tail point toward the transducer correlates strongly with the width of the echo pulse; other changes in the returning echo, including the kurtosis, also indicate the orientation of the fi sh. The next step will be to correlate echo components with other fi sh features, such as tail strength and swim speed, and to determine how those sonar characteristics vary according to species. Nailing down the differences between sockeye and chinook salmon could take years, however. Mulligan insists the signifi cance of the correlation between fi sh swimming behavior and long-ignored echo characteristics cannot be overstated. It “opens many more opportunities for fi sh-type discrimination based on behavior,” he says. Alaska’s Kenai River Sportfi shing Association, which helped to fi nance the project, evidently agrees. Its hope: that conservation officials will have more accurate assessments of the yearly salmon runs up the Kenai and other riv- ers and be able to identify fi sh by species before netting or reeling them in. That could settle disputes between offi cials and fi shers over just how much salmon can be harvested.

David Kosub is based in Victoria, B.C.

olids and liquids could hardly seem of the helium; the oscillations occurred more more different, one maintaining a rig- rapidly when the inertia went down, just as S id shape and the other fl owing to fi t the if the mass of the helium decreased. Amaz- contours of whatever contains it. And of all ingly, they found that about 1 percent of the the things that slosh and pour, superfl uids helium ring remained motionless while the seem to capture the quintessence of the liq- other 99 percent continued rotating as nor- uid state—running through tiny channels mal. One solid could somehow move effort- with no resistance and even dribbling uphill lessly through another. to escape from a bowl. So how can a solid behave like a super- A superfl uid solid sounds like an oxymo- fl uid? All bulk liquid superfl uids are caused ron, but it is precisely what researchers at by Bose-Einstein condensation, which is the Pennsylvania State University have recently quantum process whereby a large number of witnessed. Physicists Mo- particles all enter the same ses Chan and Eun-Seong quantum state. Chan and Kim saw the behavior in Kim’s result therefore sug- helium 4 that was com- gests that 1 percent of the pressed into solidity and atoms in the solid helium chilled to near absolute somehow form a Bose- zero. Although the super- Einstein condensate even solid behavior had been while they remain at fi xed suggested as a theoretical lattice positions. That possibility as long ago as seems like a contradiction 1969, its demonstration in terms, but the exchange poses deep mysteries. of atoms between lattice Rotation is one way sites might allow it. A ) THE IMPORTANCE that superfl uids reveal their characteristic of helium bottom OF BEING PURE peculiar properties. Take a would tend to promote Pennsylvania State University bucket of ordinary liquid such an exchange—name- physicists Moses Chan and Eun- helium and rotate it slowly, ly, its large zero-point Seong Kim recently succeeded in then cool it down to about Filling motion, which is the in-

line ( READING LUCY ); creating a solid that acts like a two kelvins, so that some herent jiggling of atoms top superﬂ uid. They used helium 4 of the helium becomes su- that represents a mini- ( (the original superﬂ uid, which Magnesium goes “super” when the liquid is perfluid. The superfluid disk mum amount of move- cooled below 2.17 kelvins) that fraction will not rotate. Be- Solid helium ment required by quan- was extremely pure. It contained cause part of the helium is tum uncertainty. (It is the Aluminum shell no more than 0.3 part per million motionless, the amount of SUPERSOLID HELIUM partly rotates reason helium ordinarily of helium’s other isotope, helium 3 force required to set the and partly stays still as its suspended only occurs as a gas or a (which goes super in a more aluminum-shelled container rotates. complicated fashion at the much bucket and helium rotating liquid: the extremely light-

chillier temperature is less than it would be oth- weight atoms jiggle about Pennsylvania State University of two millikelvins). erwise. Technically, the helium’s rotational too much to form a solid.) Supporting the inertia decreases. idea of condensation, the two researchers did In a previous experiment, using Chan and Kim observed such a decrease not see superfl uidity in solid helium 3, an iso- helium embedded in the nanoscopic interstices of porous of rotational inertia in a ring of solid helium. tope of helium that as a liquid undergoes a glass, the two physicists They applied about 26 atmospheres of pres- kind of condensation and becomes superfl uid observed evidence of sure to liquid helium, forcing the atoms to only at temperatures far below that needed supersolidity, but only in samples lock in place and thereby form a fi xed lattice. by liquid helium 4. containing less than 0.01 percent They observed the oscillations of the helium Another possibility is that the crystal of helium 3. The results suggest why previous efforts to observe as it twisted back and forth on the end of a helium contains numerous defects and lat- supersolid helium failed— metal rod. The period of these torsional os- tice vacancies (yet another effect of the zero-

insufﬁ ciently pure helium. cillations depended on the rotational inertia point motion). These defects and vacancies PASSANEAU,JOHN COURTESY MOSES CHEN, OF

24 SCIENTIFIC AMERICAN JANUARY 2005 COPYRIGHT 2004 SCIENTIFIC AMERICAN, INC. could be what, in effect, undergo Bose-Ein- ity in helium 3, calls the lack of pressure news stein condensation. dependence “more than a bit bewildering.” SCAN But all those theories seem to imply that He says that Chan and Kim have done “all the superﬂ uidity would vary with the pres- the obvious experiments to search for some sure, yet Chan and Kim see roughly the artifact.” If they are correct, Osheroff adds, same effect all the way from 26 to 66 atmo- then “I don’t understand how supersolids spheres. Douglas D. Osheroff of Stanford become super. I hope the theorists are think- University, the co-discoverer of superﬂ uid- ing about it seriously.”

ASTRONOMY Through Titan’s Haze SATURN MOON HAS A SURFACE THAT IS DYNAMIC— AND PUZZLING BY CHARLES Q. CHOI

fter taking spectacular close-ups of Saturn and its rings, the Cassini space- A craft turned its attention to Titan, Saturn’s largest moon. Using imaging radar, the spacecraft peered through Titan’s smog blanket—its thick orange atmosphere, consisting primarily of nitrogen and trace amounts of at least a dozen kinds of organ- ic compounds, extends hundreds of kilometers above the surface. Making its closest approach of 1,200 kilometers on October 26, Cassini was able to resolve features down to 300 meters across while traveling at 21,800 kilometers per hour. It mapped roughly 1 percent of a satellite world larger than either Mercury or Pluto. The images returned so far have aston- ished scientists. Cassini has not detected any signs of the long-predicted gasolinelike seas of methane, propane or butane that are speculated to be as much as three kilometers deep. But investigators were quick to point ICY “LAVA” is one explanation for the “oozing” seen out that the data did not preclude their ex- on the surface of Titan. This artist rendition is istence, either. Perhaps more surprising, based on Cassini data, such as the image showing Cassini found hardly any evidence of impact surface material streaking across the moon (right). craters. The lack of craters suggests that Ti-

) tan, made of equal parts water ice and rocky dubbed “the Halloween cat,” might be a matter, is continuously reshaping itself. lake, judging by its relative smoothness. On bottom

I ( Indeed, one strikingly bright feature Christmas Eve, Cassini was to have de- C looks very much like something oozed ployed the European Space Agency’s piggy- across the freezing (–178 degrees Celsius) backed Huygens probe to streak through surface—perhaps icy “lava” spewed by a the moon’s atmosphere for a better look. If

); NASA/JPL/SS); “cryovolcano.” Elsewhere, streaks on the all goes well, it will land—or splash down— top surface could be ﬂ owing liquid hydrocar- on Titan on January 14. bons, a moving ice sheet like a glacier, or matter blown over the ground by wind. An- Charles Q. Choi, based in New York City,

RON MILLER ( other region resembling a feline’s head, is a frequent contributor.

ew invasive species play their threat- Two years later they got a troubling an- ening parts with as much panache as swer: the fi sh, Channa argus, turned up in F the northern snakehead. With its the waters of the Potomac River, the result toothy mug, scaly head, predatory nature of one or perhaps multiple releases along its and decidedly unfi shlike need to breathe shores. In May an angler caught a female in air, this interloper from the waters of east- a Virginia tributary, and as the summer ern Asia made headlines as “Frankenfi sh” progressed, the river’s tally rose to 19. The biggest blow came September 29, when a juvenile northern snakehead fell out of the aquatic weeds tangled around a boat trailer that was pulled from Virginia’s Dogue Creek, another tributary. The result of a midsummer spawn, the juvenile points to a reproducing population in a waterway with tens of thousands of acres of habitat. “This time you can’t get rid of them,” says Walter Courtenay, Jr., a U.S. Geological Survey research fi shery biologist. No clear control measures exist. Because anglers have caught most of the Potomac snakeheads, wildlife offi cials are bringing the fi shing community onboard in their removal efforts. It is not known, however, if fi shing will make a signifi cant difference. Traditional sampling techniques, using special nets or electric current to stun fi sh, do not work well in the shallow, heavily vege- tated areas that northern snakeheads prefer. “Prevention was everything,” explains Steve Minkkinen, a fi sheries biologist with the U.S. Fish and Wildlife Service. “Once they PROBLEM FOR get out there, it can be very diffi cult.” THE POTOMAC Offi cials will keep sampling the river No one can say for sure how and educating the public, but “it’s going to FUTILE FIGHT? Battle against snakeheads in Pine a growing population of northern take time to see what happens,” Courtenay Lake in Wheaton, Md., began in April with temporary snakeheads, with no natural removal of native fi sh before lake drainage (top). But says. Based on the precedent set by other predators, will affect the Potomac adults later turned up in the Potomac River (bottom). nonnative species, the outcome is not prom- River. “We really have nothing on which to base an opinion,” says ising. The European green crab, another Becky Wajda, assistant division when it was discovered in a Maryland pond predatory invader with a taste for native director with the Virginia in 2002. Worried that a heavy rain could clams and crabs, caused a fi ve- to 10-fold Department of Game and Inland wash the fi sh into the nearby Little Patux- decrease in their populations three years af- Fisheries. The fi sh have yet ent River—harming native species in a ter arriving in Bodega Bay Harbor, Calif. to establish long-standing U.S. populations, and little is known large, open ecosystem—wildlife offi cials Nor is the northern snakehead very likely to about the species, such as what poisoned the pond, killing a population of remain an East Coast problem: in October

keeps it in check in its native some 1,300 northern snakeheads that most an angler caught an adult in Burnham Har- waters. Most worrisome is the likely began with a local resident’s release bor in Lake Michigan. “The problem is, it invader’s probable effect on of a few ﬁ sh. Having launched a public edu- only takes one person” to let an invasive spe- Photo AP the area’s prized largemouth bass population, because it will cation campaign on the dangers of freeing cies loose, says Steve Early, a biologist in the compete for the same food nonnative species in the wild, officials Maryland Fisheries Service. “People just

and habitat. hoped the snakehead was gone for good. don’t recognize the consequences.” HOUSTON MATT

26 SCIENTIFIC AMERICAN JANUARY 2005 COPYRIGHT 2004 SCIENTIFIC AMERICAN, INC. news SCAN GEOPHYSICS Shaky Gravity Boost Earthquakes jostle matter within the crust, thereby modifying local gravity. But because of imprecise, unstable instruments, scientists could monitor these changes only with the aid of long records before and after quakes. Japanese investigators have devised a much quicker method. They monitored how superconducting balls respond to gravity while trapped floating in ultrastable magnetic fi elds generated by superconducting coils. After accounting for the separate pulls of the sun, moon, air, ocean and the earth’s rotation, the researchers detected a DATA POINTS: permanent increase in gravity roughly a CLEARING THE AIR half billionth that of the earth’s pull south- In maintaining clean rooms, east off the coast of Hokkaido, the epicenter engineers try to keep out particles of the magnitude 8 Tokachi-oki quake in 0.5 micron and larger. A key device 2003. The results, in the October 15 Sci- is the high-effi ciency particulate ence, agree with theoretical predictions, air (HEPA) fi lter, which traps at suggesting that superconducting gravime- least 99.97 percent of particulates 0.3 micron wide. (It does even ters can help satellites chart the earth’s grav- better with bigger particulates.) ity to map changes in polar ice cap thick- Other measures, however, must be ness, seawater levels, atmospheric density TREMORS can modify the local gravitational force. included, because additional and planetary geology. —Charles Q. Choi particulates are constantly being created—walking, for instance, generates about fi ve million of HEALTH them per minute. For ultralow penetration air (ULPA) fi lters, the Mercurial Spread target is 0.12 micron with

99.999 percent efﬁ ciency. A neurotoxic poison, mercury is especially of the metal in their systems. Researchers at COLLINS MATT BY ILLUSTRATION ); worrisome to developing fetuses. A nation- the University of North Carolina at Asheville

Number of particles less than bottom 0.5 micron wide suspended in wide study reveals that a signiﬁ cant number based their results on hair samples from ( a cubic foot of air in: of women of child-bearing age have too much nearly 1,500 people of all ages. As hair Ofﬁ ce building: 500,000 to grows, it incorporates mercury from 1 million the bloodstream. Interim results from Room in a U.S. home: 350,000 the Greenpeace-commissioned sur-

Hospital operating room: 1,000 vey released October 20 revealed that Library Photo Science to 10,000 one ﬁ fth of those studied had mer- NASA clean room: 100 cury levels above the EPA recommen- Computer-chipmaking clean dation of one part per million in hair. room: 10 to 1,000

The investigators report no other WIERSMA DIRK ); Biohazard Level 4 lab: 10 top

pollutant has anywhere near this ( Typical size, in microns: high a percentage of the U.S. popula-

Bacterium: 1 to 10 tion with exposure levels above fed- Photo AP Virus: 0.02 to 0.45 eral standards. The biggest sources of Compiled by Barry E. DiGregorio airborne mercury are coal-ﬁ red pow-

SOURCES: NASA; Coastwide er plants. The investigators will gath- Laboratories; The Quarantine and er an estimated 5,000 samples or Certification of Martian Samples (National Academies Press, 2002); more in total and issue their ﬁ nal re- Wikipedia.org, orders of MERCURY exposure appears far too common.

magnitude (length) port in March. —Charles Q. Choi ARBOGAST REX CHARLES

Some animals signal vitality through high- male paper wasps with larger, more frag- maintenance “badges of status,” such as the mented or blotchier black markings above peacock’s plume, whereas others have badg- their mouths tend to win in clashes for domi- es that seem to impose no inherent cost to the nance. When the researchers painted the creature, raising the question of why such in- wasps to give them the markings of higher or dividuals do not simply cheat. Researchers lower dominance, they found that both kinds surmise that social punishment of liars keeps of liars were harassed more than unpainted such signals truthful. Now entomologists wasps, indicating that the wasps frown on ly- have observed the ﬁ rst unequivocal evidence ing per se. The investigators, who describe supporting the idea. They discovered that fe- their work in the November 11 Nature, suspect that some behavioral or chemical cue gives the liars away. —JR Minkel

BIOLOGY BRIEF Eyeing Stem Cells POINTS ■ Rather than just an X-Y pair, the Humans appear to have true, self-renewing duck-billed platypus requires ﬁ v e c h r o m o s o m a l p a i r s t o retinal stem cells. Brenda Coles and her col- determine sex. One pair has leagues at the University of Toronto minced avian similarity, suggesting that up eyes donated from deceased people and the sex-determining systems cultured the cells. They found that about of birds and mammals may PAPER WASPS don’t put up with phonies. one in 500 cells from the black ring around be linked. Nature online, October 24, 2004; the iris could divide indeﬁ nitely and adopt Proceedings of the National MEMORY the full variety of retinal cell types. (Past Academy of Sciences USA, studies had found retinal stem cells of lim- November 16, 2004

Alternative Reality ited capacity, unable to divide indeﬁ nitely ■ Selling aspirin and and transforming into only a few cell types.) acetaminophen in smaller doses In “Just My Imagination,” the Temptations When transplanted into embryonic mice or reduced the suicide rate from sang of a vision that “couldn’t be a dream, chicks, the stem cells turned into cells of the these drugs by nearly 25 percent for too real it all seems.” Scientists now have type found in that animal at that stage of and the need for liver transplants from related damage by 30 pinpointed how the imagination can make development. Their next experiment, Coles percent in the U.K., where 1998 false memories. Volunteers lying in a mag- says, is to transplant the cells into mice with legislation cut the package sizes.

) netic resonance imaging scanner were shown degenerating retinas to see if they restore BMJ, Novenber 6, 2004 a list of words and told to picture each item. function and later to ﬁ gure out how to acti-

bottom ■ According to rat studies, ( For half the words, a photograph of the vate and manipulate them. See the Novem- matching object was ﬂ ashed. Afterward, vol- ber 2 Proceedings of the National Academy alcoholics who lay off the hooch might restore their ability unteers listened to a random sequence of of Sciences USA. —JR Minkel to grow new neurons, words corresponding either to photographs a process inhibited by they saw, to objects they were only told to alcohol dependency. imagine, or to items neither seen nor imag- Journal of Neuroscience, Science Photo Library ined. When volunteers falsely remembered October 27, 2004 seeing photographs of objects they had only ■ New evidence conﬁ rms not only imagined, brain regions critical to generat- the presence of methane on ing images became highly activated. Mental Mars but also larger quantities ); DAVID PARKER PARKER DAVID ); images created by these areas leave traces in of it than previously inferred. top the brain that are later mistaken for objects The gas could have originated actually perceived, suggest researchers at from biological processes. Northwestern University in the October Psy- American Astronomical Society IRIS could be a source for stem cells. meeting, November 11;

E. A. TIBBETTS ( TIBBETTS A. E. chological Science. —Charles Q. Choi www.sciam.com/ontheweb

t least since the 1990s, the U.S. has the work is physically demanding: it is so faced a growing shortage of registered strenuous that nurses generally cannot work nurses. According to the Department much beyond their mid-50s. Indeed, the top A DHHS of Health and Human Services ( ), in concerns of nurses are their increasing work- 2020 the demand for nurses could exceed load and long hours. the supply by 40 percent if nothing is done Furthermore, pay lags behind other oc- FAST FACTS: to stop this trend. The 20th century has seen cupations that have similar educational re- recurrent shortages, but this one is differ- quirements: an elementary schoolteacher, WEAK WAGES ent, in part because of an unprecedented for example, earned $14,000 more than a Average hourly pay of: demographic squeeze. The workforce made nurse in 2001, according to the DHHS. Reg- up of those aged 20 to 35, the prime recruit- istered nurses are leaving the workforce at Registered nurse: $25.96 ing pool for nurses, will decline at the same a faster rate than ever: currently, almost Physical therapist: $28.07 time baby boomers begin to reach retire- 500,000 RNs do not work in nursing. Dental hygienist: $29.66 ment and consume medical services at a Demand for nurses is rising because of Elementary schoolteacher: faster rate. But perhaps a more important population growth, more elderly persons $31.74 factor is the low status of nurses. At one and medical advances that require greater Secondary schoolteacher: time, low status was far less of a deterrent, skill. Health industry economics also drives $31.88 but now, when virtually all professions are demand. Since 1990, an average of 85 per- SOURCE: Bureau of Labor Statistics, open to women, nursing has become a rela- cent of the population have had some form National Compensation Survey. Data from July 2003. tively unattractive career choice. Moreover, of health insurance and so have been cov- 3 ered, at least partially, for nursing care. At the same time, real per capita disposable in- come has grown steadily, making it easier 2.5 Projected demand to pay for noncovered health care. Nursing seems to defy the normal laws of supply and demand, given that pay has 2 FURTHER Projected supply lagged at a time of higher demand. A possi- READING ble explanation lies in the superior bargain- 1.5 ing power of hospitals—the major employers Health Care’s Human Crisis: Actual supply of RNs—combined with the relative lack of The American Nursing organization of nurses. Only 38 percent of

Bobbi Kimball and Registered Nurses in the U.S. (millions) Shortage. 1 Edward O’Neil. Robert Wood hospital nurses are unionized. Another fac- 1980 1990 2000 2010 2020 tor affecting pay is the failure of nurses to Johnson Foundation, April 2002. Year www.rwjf.org 40 develop a strong constituency among the general public. In contrast, schoolteachers 2000 Projected Supply, Demand, 2020 have forged strong community bonds and Shortages of Registered (Projected) Nurses: 2000–2020. National 30 1980 through local parent-teacher organizations. Center for Health Workforce Broadening the recruitment base—nurs- Analysis, U.S. Department es are now 86 percent white—would help al- of Health and Human 20 leviate the shortage, but long-term solutions Services, July 2002. most likely will have to deal with the more http://bhpr.hrsa.gov/ fundamental nature of the ﬁ eld. In addition Changing Demographics: 10 to higher wages, the key to resolving the Implications for Physicians,

Percent of All Registered Nurses shortage may lie in giving nurses more pow- Nurses, and Other Health er over working conditions and over health Workers. National Center care decisions now made by physicians. for Health Workforce Analysis, 0 U.S. Department of Health and < 3030–39 40–49 50–59 > 60 Human Services, Spring 2003. Age Range (years) Rodger Doyle can be reached at

http://bhpr.hrsa.gov/ SOURCE: U.S. Department of Health and Human Services [email protected] DOYLE RODGER

Quantum Quackery A surprise-hit film has renewed interest in applying quantum mechanics to consciousness, spirituality and human potential By MICHAEL SHERMER

In spring 2004 I appeared on KATU TV’s AM Northwest in structural scaffolding. Their conjecture (and that’s all it is) is Portland, Ore., with the producers of an improbably named that something inside the microtubules may initiate a wave- fi lm, What the #$*! Do We Know?! Artfully edited and fea- function collapse that results in the quantum coherence of at- turing actress Marlee Matlin as a dreamy-eyed photographer oms. The quantum coherence causes neurotransmitters to be trying to make sense of an apparently senseless universe, the released into the synapses between neurons, thus triggering fi lm’s central tenet is that we create our own reality through them to fi re in a uniform pattern that creates thought and con- consciousness and quantum mechanics. I never imagined that sciousness. Because a wave-function collapse can come about such a fi lm would succeed, but it has grossed millions. only when an atom is “observed” (that is, affected in any way The fi lm’s avatars are New Age scientists whose jargon- by something else), the late neuroscientist Sir John Eccles, an- laden sound bites amount to little more than what California other proponent of the idea, even suggested that “mind” may Institute of Technology physicist and Nobel laureate Murray be the observer in a recursive loop from atoms to molecules to Gell-Mann once described as “quantum fl apdoodle.” Univer- neurons to thought to consciousness to mind to atoms.... sity of Oregon quantum physicist Amit Gos- In reality, the gap between subatomic wami, for example, says in the fi lm: “The ma- What the #$*! quantum effects and large-scale macro sys- terial world around us is nothing but possible is going on here? tems is too large to bridge. In his book The movements of consciousness. I am choosing Unconscious Quantum (Prometheus Books, moment by moment my experience. Heisenberg said atoms are 1995), University of Colorado physicist Victor Stenger dem- not things, only tendencies.” Okay, Amit, I challenge you to onstrates that for a system to be described quantum-mechan- leap out of a 20-story building and consciously choose the ically, its typical mass (m), speed (v) and distance (d) must be experience of passing safely through the ground’s tendencies. on the order of Planck’s constant (h). “If mvd is much greater The work of Japanese researcher Masaru Emoto, author than h, then the system probably can be treated classically.” of The Hidden Messages in Water, is featured to show how Stenger computes that the mass of neural transmitter mole- thoughts change the structure of ice crystals—beautiful crys- cules and their speed across the distance of the synapse are tals form in a glass of water with the word “love” taped to it, about two orders of magnitude too large for quantum effects whereas playing Elvis’s “Heartbreak Hotel” causes other crys- to be infl uential. There is no micro-macro connection. Then tals to split in two. Would his “Burnin’ Love” boil water? what the #$*! is going on here? The fi lm’s nadir is an interview with “Ramtha,” a 35,000- Physics envy. The lure of reducing complex problems to year-old spirit channeled by a woman named JZ Knight. I basic physical principles has dominated the philosophy of sci- wondered where humans spoke English with an Indian accent ence since Descartes’s failed attempt some four centuries ago 35,000 years ago. Many of the fi lms’ participants are members to explain cognition by the actions of swirling vortices of at- of Ramtha’s “School of Enlightenment,” where New Age pab- oms dancing their way to consciousness. Such Cartesian ulum is dispensed in costly weekend retreats. dreams provide a sense of certainty, but they quickly fade in The attempt to link the weirdness of the quantum world to the face of the complexities of biology. We should be explor- mysteries of the macro world (such as consciousness) is not new. ing consciousness at the neural level and higher, where the The best candidate to connect the two comes from University arrow of causal analysis points up toward such principles as of Oxford physicist Roger Penrose and physician Stuart Ham- emergence and self-organization. Biology envy. eroff of the Arizona Health Sciences Center, whose theory of quantum consciousness has generated much heat but little light. Michael Shermer is publisher of Skeptic (www.skeptic.com)

Inside our neurons are tiny hollow microtubules that act like and author of The Science of Good and Evil. BRAD HINES

You, Robot He says humans will download their minds into computers one day. With a new robotics ﬁ rm, Hans Moravec begins the journey from warehouse drones to robo sapiens By CHIP WALTER

When word got around that Hans Moravec had found- adept and adaptive species? Somehow, creating a com- ed an honest-to-goodness robotics fi rm, more than a pany seemed ... uncharacteristically pragmatic. few eyebrows were raised. Wasn’t this the same Car- But Moravec doesn’t see it that way. He says he negie Mellon University scientist who had predicted didn’t start Seegrid Corporation because he was back- that we would someday routinely download our minds ing off his predictions. He founded the company be- into robots? And that exponential advances in comput- cause he was planning to help fulfi ll them. “It was ing power would cause the human race to invent itself time,” he says, slowly rubbing his hand across his out of a job as robots supplanted us as the planet’s most bristle-short hair. “The computing power is here.” The 56-year-old Moravec should know. Born in Kautzen, Austria, and raised in Montreal, he has been pushing the envelope on robotics theory and experi- mentation for the past 35 years, fi rst as the graduate student at Stanford University who created the “Stan- ford Cart,” the fi rst mobile robot capable of seeing and autonomously navigating the world around it (al- beit very slowly), and later as a central force in Car- negie Mellon’s vaunted Robotics Institute. His icono- clastic theories and inventive work in machine vision have both shocked his colleagues and jump-started research; Seegrid is just the next logical step. Moravec pulls an image up onto one of the two massive monitors that sit side by side on his desk, like great unblinking eyes. It’s six o’clock in the evening, but an inveterate night owl, he’s just starting his “day.” “I have been drawing these graphs for years about what will be possible,” he comments. His mouse roams along dots and images that plot and compare the processing power of old top-of-the-line computers with their biological equivalents. There is the ENIAC, for example, that in 1946 possessed the processing capac- HANS MORAVEC: A FUTURE OF ROBOTS ity of a bacterium and then a 1990 model IBM PS/2 90 ■ Constructed his first robot at age 10 out of tin cans, batteries, a motor that once harnessed the digital horsepower of a worm. and lights; as a child, deeply affected by science fiction, especially Only recently have desktop computers arrived that can the writings of A. E. van Vogt and Arthur C. Clarke. deliver the raw processing muscle of a spider or a gup- ■ Predicts that by 2040 faster processing will enable robots to become py (about one billion instructions per second). “At self-aware and experience emotions. guppy-level intelligence,” he explains, “I thought we ■ Why a robotics industry is necessary for real advances: “I’ve seen could manage 3-D mapping and create a robot that robotics research at universities, and it’s pretty interesting, but it’s could get around pretty well without any special prep-

primarily a lot of one-shot projects.” aration of its environment.” GOLDSMITH SCOTT

15 But no one was creating that 10 same information keeps coming robot, so in the late 1990s up, then the program decides that Moravec says he began to grow 1012 it’s probably really there,” Human “very antsy” about getting one Mac G5/Dual 2.0 GHz Moravec explains. The robot then built. In 1998 he wrote an ambi- Sony Playstation II knows to stop or roll around it. 9 Mouse tious grant proposal that outlined 10 Cray-1 This approach is how you might DEC VAX 11/780 Gateway- Guppy software for a robotic vision sys- 486DX2/66+ make your way through a dark tem. The Defense Advanced Re- 106 room with a fl ashlight, in which IBM PC search Projects Agency quickly Commodore 64 Worm you slowly build up a mental pic- IBM 7040 funded the proposal, and three Apple II ture of what is around. 3 and a half years and $970,000 10 UNIVAC I Creating warehouse drones ENIAC later, with PCs just reaching gup- second) per (instructions Power Brain Bacterium as a fi rst step toward the startling py smarts, a working demonstra- 1 robotic world Moravec foresees tion was complete. 1940 1960 1980 2000 2020 2040 might seem an unlikely conces- Year “It proved the principle,” sion to reality. But those who RAW COMPUTING MUSCLE, as exemplifi ed by a plot of 120 top Moravec says. “We really could machines of their time since 1940, is today on par with the brain know Moravec say it is no sur- map with stereo vision, if we did of a guppy. It may reach the human equivalent around 2040. prise: he is an unusual mix of things just right.” But doing things whimsy, wild vision and rigorous just right required more than prototype software. Robotic evo- pragmatism. He has been known to be so lost in thought dur- lution, he adds, “has to be driven forward by a lot of trial and ing his daily walks to his offi ce that he bumps into mailboxes, error, and the only way to get enough is if you have an industry yet none of that eccentricity has tarnished his reputation as a where one company is trying to outdo another.” To help things fi rst-rate engineer and programmer. along, he and Pittsburgh physician and entrepreneur Scott “Some of Hans’s ideas are pretty outrageous,” admits Raj Friedman founded Seegrid in 2003. Their focus: the unglamor- Reddy, who as director of the Robotics Institute brought ous but potentially huge “product handling” market. Moravec to Carnegie Mellon in 1980, “but his work has always Industrial robots already fl ourish in tightly constrained been very practical.” Seegrid co-founder Friedman says it is environments such as assembly lines. Where they fail is in loca- exactly Moravec’s vision and dogged persistence that separates tions loaded with unpredictability. So Seegrid concentrated on him from the pack: “He’s a genius, and he works hard.” creating vision systems that enable simple machines to move The same themes run through his view of the future of ro- supplies around warehouses without any human direction. botics. Evolution moves in tiny steps, Moravec notes, but ac- Not exactly the stuff of science fi ction, Moravec agrees, complishes amazing things. Machine evolution will do the and a long way from superintelligent robots, but he says you same as it incrementally nudges robots from their clumsy behave to start somewhere. Nearly everything sold has to be ginnings to the heights of human-level intelligence and mobil- warehoused at some point, and at some point it also has to be ity. “We don’t need a lot of Einsteins to do this; we need a lot rerouted and shipped. Right now human workers move mil- of engineers working diligently to make little improvements lions of tons of supplies and products using dollies, pallet and then test them out in the marketplace,” Moravec insists. jacks and forklifts. Seegrid’s fi rst prototype devices automate And that, he says, will ultimately lead to robots becoming vast- that work, turning wheeled carts into seeing-eye machines ly more intelligent and adaptable than we are. that can be loaded and then walked through various routes to That seems to leave us only one destination: the endangered teach them how to navigate on their own. The technology is species list. “Something like 99 percent of all species go ex- built on Moravec’s bedrock belief that if robots are going to tinct,” Moravec observes. Why, he asks, should we be any dif- succeed, the world cannot be adapted to them; they have to ferent? Not that he sees us being destroyed by what he calls our adapt to the world, just like the rest of us. “mind children” exactly. “It’s not going to be like Terminator,” Other approaches can guide robots, but they typically rely he reassures. But children do often exceed the accomplishments on costly, precision hardware such as laser range fi nders or on of their parents. And in our evolutionary dotage, he is sure they extravagant arrangements that prewire and preprogram the will take good care of us, as parents’ children often do. “They machines to move through controlled spaces. Seegrid’s system will create the perfect welfare state,” he says. uses off-the-shelf CCD cameras and simple sonar and infrared At least, we hope so. sensors. Although these components gather imprecise information, the software compensates. It statistically compares the Chip Walter is working on his third science book,

gathered data to develop a clean, accurate 3-D map. “If the Six Traits (That Make Us Human). READING LUCY

37A SCIENTIFIC AMERICAN JANUARY 2005 COPYRIGHT 2004 SCIENTIFIC AMERICAN, INC. INITIAL ENCOUNTER with germs, or pathogens, sets off the “innate” arm of the immune system, which turns out to be more sophisticated than anyone guessed. Immunity’s Early-Warning

System By Luke A. J. O’Neill The innate immune response constitutes the ﬁ rst line of defense against invading microbes and plays a role in inﬂ ammatory disease. Surprising insights into how this system operates could lead to new therapies for a host of infectious and immune-related disorders

woman is riding an elevator when her fellow passen- Discovery of TLRs has generated an excitement among gers start to sneeze. As she wonders what sort of sick- immunologists akin to that seen when Christopher Columbus ness the other riders might be spreading, her immune returned from the New World. Scores of researchers are now system swings into action. If the bug being dispersed setting sail to this new land, where they hope to fi nd explana- Aby the contagious sneezers is one the woman has met before, tions for many still mysterious aspects of immunity, infection a battalion of trained immune cells—the foot soldiers of the and disorders involving abnormal defensive activity. Study of so-called adaptive immune system—will remember the spe- these receptors, and of the molecular events that unfold after cifi c invader and clear it within hours. She might never realize they encounter a pathogen, is already beginning to uncover she had been infected. targets for pharmaceuticals that may enhance the body’s pro- But if the virus or bacterium is one that our hapless rider has tective activity, bolster vaccines, and treat a range of devastat- never wrestled, a different sort of immune response comes to ing and potentially deadly disorders. the rescue. This “innate” immune system recognizes generic classes of molecules produced by a variety of disease-causing Cinderella Immunity agents, or pathogens. When such foreign molecules are detect- until about five years ago, when it came to the im- ed, the innate system triggers an infl ammatory response, in mune system, the adaptive division was the star of the show. which certain cells of the immune system attempt to wall off Textbooks were fi lled with details about B cells making anti- the invader and halt its spread. The activity of these cells—and bodies that latch onto specifi c proteins, or antigens, on the sur- of the chemicals they secrete—precipitates the redness and face of an invading pathogen and about T cells that sport recep- swelling at sites of injury and accounts for the fever, body aches tors able to recognize fragments of proteins from pathogens. and other fl ulike symptoms that accompany many infections. The response is called adaptive because over the course of an The infl ammatory assault, we now know, is initiated by infection, it adjusts to optimally handle the particular micro- Toll-like receptors (TLRs): an ancient family of proteins that organism responsible for the disease. mediate innate immunity in organisms from horseshoe crabs Adaptive immunity also grabbed the spotlight because it to humans. If TLRs fail, the entire immune system crashes, endows the immune system with memory. Once an infection leaving the body wide open to infection. If they work too has been eliminated, the specially trained B and T cells stick hard, however, they can induce disorders marked by chronic, around, priming the body to ward off subsequent attacks. harmful infl ammation, such as arthritis, lupus and even car- This ability to remember past infections allows vaccines to

diovascular disease. protect us from diseases caused by viruses or bacteria. Vac- SALZANO JAMES

www.sciam.com SCIENTIFIC AMERICAN 39 COPYRIGHT 2004 SCIENTIFIC AMERICAN, INC. THE DIVISIONS OF THE IMMUNE SYSTEM The mammalian immune system has two overarching contain a pathogen, the adaptive division (right side) kicks in, divisions. The innate part (left side) acts near entry points mounting a later but highly targeted attack against into the body and is always at the ready. If it fails to the speciﬁ c invader.

Pathogen Antimicrobial T cell recognizing Injury molecules a specific antigen

B cell receptor Antigen Dendritic Macrophage cell B cell Infected cell displaying Monocyte antigen Cytokines Activated B cell and other (plasma cell) inflammatory proteins T cell attacking Macrophage infected cell

Antibody

Memory T cell Neutrophil Blood vessel Memory B cell

INNATE IMMUNE SYSTEM ADAPTIVE IMMUNE SYSTEM This system includes, among other components, antimicrobial This system “stars” B cells and T cells. Activated B cells secrete molecules and various phagocytes (cells that ingest and destroy antibody molecules that bind to antigens—specifi c components unique pathogens). These cells, such as dendritic cells and macrophages, to a given invader—and destroy the invader directly or mark it for also activate an infl ammatory response, secreting proteins called attack by others. T cells recognize antigens displayed on cells. Some cytokines that trigger an infl ux of defensive cells from the blood. T cells help to activate B cells and other T cells (not shown); other T cells Among the recruits are more phagocytes—notably monocytes directly attack infected cells. T and B cells spawn “memory” cells that (which can mature into macrophages) and neutrophils. promptly eliminate invaders encountered before.

cines expose the body to a disabled form nents—including antibacterial enzymes ever, immunologists were tiptoeing of a pathogen (or harmless pieces of it), in saliva and an interlocking set of pro- around a dirty little secret: the adaptive but the immune system reacts as it would teins (known collectively as the comple- system does not work in the absence of to a true assault, generating protective ment) that kill bacteria in the blood- the allegedly more crude innate response. memory cells in the process. Thanks to stream—were felt to be less sophisticated The innate system produces certain sig- T and B cells, once an organism has en- than targeted antibodies and killer naling proteins called cytokines that not countered a microbe and survived, it be- T cells. What is more, the innate immune only induce infl ammation but also acti- comes exempt from being overtaken by system does not tailor its response in the vate the B and T cells that are needed for the same bug again. same way that the adaptive system does. the adaptive response. The posh sister, it The innate immune system seemed In dismissing the innate immune re- turns out, needs her less respected sibling rather drab in comparison. Its compo- sponse as dull and uninteresting, how- to make her shine. By the late 1990s immunologists Innate Immunity knew a tremendous amount about how Overview/ the adaptive immune system operates. ■ Innate immunity serves as a rapid response system for detecting and clearing But they had less of a handle on innate infections by any infectious agent. The response is mediated by a family of immunity. In particular, researchers did molecules called Toll-like receptors (TLRs), made by many defensive cells. not understand how microbes activate ■ When TLRs detect an invader, they trigger the production of an array of the innate response—or exactly how this signaling proteins that induce infl ammation and direct the body to mount stimulation helps to drive the adaptive a full-fl edged immune response. response of T and B cells. Soon after, ■ If TLRs are underactive, the immune system fails; if overactive, they can give though, they would learn that much of rise to disorders such as rheumatoid arthritis and even cardiovascular disease. the answer lay with the TLRs, which are Learning how to manipulate TLRs or the proteins with which they interact could produced by various immune system provide new options for treating infectious and infl ammatory diseases. cells. But the path scientists traveled to get

to these proteins was a circuitous one, TAMI TOLPA

40 SCIENTIFIC AMERICAN JANUARY 2005 COPYRIGHT 2004 SCIENTIFIC AMERICAN, INC. winding through studies of fruit fl y devel- which raise an alarm that recruits other (LPS), made by a large class of bacteria, opment, the search for drugs to treat ar- cells to the site of infection and puts the stimulates a powerful immune response. thritis, and the dawn of the genomic era. immune system in general on full alert. In humans, exposure to LPS causes fever Dendritic cells ingest invading microbes and can lead to septic shock—a deadly Weird Protein and head off to the lymph nodes, where vascular shutdown triggered by an over- the path actually had its begin- they present fragments of the pathogen’s whelming, destructive action of immune nings in the early 1980s, when immu- proteins to armies of T cells and release cells. LPS, it turns out, evokes this in- nologists started to study the molecular cytokines—activities that help to switch fl ammatory response by prompting mac- activity of cytokines. These protein mes- on the adaptive immune response. rophages and dendritic cells to release the sengers are produced by various immune To study the functions of various cytokines tumor necrosis factor-alpha cells, including macrophages and den- cytokines, researchers needed a way to (TNF-alpha) and interleukin-1 (IL-1). dritic cells. Macrophages patrol the induce the molecules’ production. They Indeed, these two cytokines were body’s tissues, searching for signs of in- found that the most effective way to get shown to rule the infl ammatory response, fection. When they detect a foreign pro- macrophages and dendritic cells to make prodding immune cells into action. If left tein, they set off the infl ammatory re- cytokines in the laboratory was to expose unchecked, they can precipitate disorders sponse. In particular, they engulf and them to bacteria—or more important, to such as rheumatoid arthritis, an autoim- destroy the invader bearing that protein selected components of bacteria. Nota- mune condition characterized by exces- and secrete a suite of cytokines, some of bly, a molecule called lipopolysaccharide sive infl ammation that leads to destruc- TOLLS IN CHARGE

Toll-like receptors (TLRs), made by many cells of the innate bacteria. Having recognized LPS, pairs of TLR4s signal to four system, have been found to both orchestrate the innate immune molecules inside the cell—MyD88, Mal, Tram and Trif—which, response and play a critical role in the adaptive response. in turn, trigger molecular interactions that ultimately activate TLR4, for example, elicits these defenses when gram-negative a master regulator of inﬂ ammation (NF- ␬B). This regulator bacteria begin to invade. TLR4 detects the incursions by binding then switches on genes that encode immune activators, to lipopolysaccharide (LPS), a sugar unique to gram-negative including cytokines. These cytokines (far right) induce inﬂ ammation and also help to switch on the T and B cells of the adaptive immune division. Gram-negative bacterium IL-1 and TNF-alpha: Enhance inflammatory LPS responses

TLR4 TLR4 IL-8: Attracts neutrophils

Mal IL-12: Promotes T cell Tram MyD88 activity

Trif

IL-6: Promotes B cell activity Activated NF-␬B

Dendritic cell

Cytokine genes Nucleus TAMI TOLPA

www.sciam.com SCIENTIFIC AMERICAN 41 COPYRIGHT 2004 SCIENTIFIC AMERICAN, INC. tion of the joints. Investigators therefore colleagues at DNA X in Palo Alto, Calif., surmised that limiting the effects of TNF- had identifi ed fi ve human Tolls, which alpha and IL-1 might slow the progress of they dubbed Toll-like receptors (TLRs). the disease and alleviate the suffering of One, TLR4, was the same human Toll those with arthritis. To design such a described by Medzhitov and Janeway. therapy, though, they needed to know At that point, researchers still did not more about how these molecules work. know exactly how TLRs might contrib- And the fi rst step was identifying the ute to human immunity. Janeway had proteins with which they interact. found that stuffi ng the membranes of In 1988 John E. Sims and his col- dendritic cells with TLR4 prompted the leagues at Immunex in Seattle discovered production of cytokines. But he could a receptor protein that recognizes IL-1. not say how TLR4 became activated FRUIT FLY that lacked the protein Toll fell victim This receptor resides in the membranes of to a rampant fungal infection; spores cover the during an infection. many different cells in the body, includ- body like a fur coat. (The head is at the bottom The answer came in late 1998, when ing macrophages and dendritic cells. The right.) This outcome, reported in 1996, was one Bruce Beutler and his co-workers at the part of the receptor that juts out of the of the fi rst indications that fruit fl ies require Toll Scripps Institute in La Jolla, Calif., found cell binds to IL-1, whereas the segment proteins for protection against disease. that mutant mice unable to respond to that lies inside the cell relays the message was looking for genes whose sequences LPS harbor a defective version of TLR4. that IL-1 has been detected. Sims exam- closely matched that of Toll and thus Whereas normal mice die of sepsis within ined the inner part of the IL-1 receptor might encode Toll-like proteins. And he an hour of being injected with LPS, these carefully, hoping it would yield some clue discovered that part of the Toll protein mutant mice survive and behave as if they as to how the protein transmits its mes- bears a striking resemblance to the inner have not been exposed to the molecule at sage—revealing, for example, which sig- part of the human IL-1 receptor, the seg- all; that is, the mutation in the TLR4 gene naling molecules it activates within cells. ment that had mystifi ed Sims. renders these mice insensitive to LPS. But the inner domain of the human IL-1 At fi rst the fi nding didn’t make sense. This discovery made it clear that receptor was unlike anything researchers Why would a protein involved in human TLR4 becomes activated when it inter- had seen before, so he was stymied. infl ammation look like a protein that acts with LPS. Indeed, its job is to sense Then, in 1991, Nick J. Gay of the tells fl y embryos which end is up? The LPS. That realization was a major break- University of Cambridge—working on a discovery remained puzzling until 1996, through in the fi eld of sepsis, because it completely unrelated problem—made a when Jules A. Hoffmann and his col- revealed the molecular mechanism that strange discovery. He was looking for laborators at CNRS in Strasbourg underlies infl ammation and provided a proteins that were similar to a fruit-fl y showed that fl ies use their Toll protein to possible new target for treatment of a protein called Toll. Toll had been identi- defend themselves from fungal infec- disorder that sorely needed effective ther- fi ed by Christiane Nusslein-Volhard in tion. In Drosophila, it seems, Toll multi- apies. Within two years, researchers de- Tübingen, Germany, who gave the pro- tasks and is involved in both embryonic termined that most TLRs—of which 10 tein its name because fl ies that lack Toll development and adult immunity. are now known in humans—recognize look weird (Toll being the German word molecules important to the survival of for “weird”). The protein helps the de- Worms, Water Fleas and You bacteria, viruses, fungi and parasites. veloping Drosophila embryo to differen- the il-1 receptor and the Toll pro- TLR2 binds to lipoteichoic acid, a com- tiate its top from its bottom, and fl ies tein are similar only in the segments that ponent of the bacterial cell wall. TLR3 without Toll look jumbled, as if they are tucked inside the cell; the bits that are recognizes the genetic material of virus- have lost their sidedness. exposed to the outside look quite differ- es; TLR5 recognizes fl agellin, a protein Gay searched the database containing ent. This observation led researchers to that forms the whiplike tails used by bac- all the gene sequences then known. He search for human proteins that resemble teria to swim; and TLR9 recognizes a Toll in its entirety. After all, evolution signature genetic sequence called CpG, LUKE A. J. O’NEILL received his Ph.D. in usually conserves designs that work which occurs in bacteria and viruses in pharmacology from the University of well—and if Toll could mediate immu- longer stretches and in a form that is London in 1985 for work on the pro- nity in flies, perhaps similar proteins chemically distinct from the CpG se- infl ammatory cytokine interleukin-1. were doing the same in humans. quences in mammalian DNA. O’Neill is Science Foundation Ireland Acting on a tip from Hoffmann, in TLRs, it is evident, evolved to recog-

THE AUTHOR Research Professor and head of the de- 1997 Ruslan Medzhitov and the late nize and respond to molecules that are partment of biochemistry at Trinity Charles A. Janeway, Jr., of Yale Univer- fundamental components of pathogens.

College in Dublin. He is founder of Op- sity discovered the ﬁ rst of these proteins, Eliminating or chemically altering any VOL. 86, NO. 6, PAGES 973–983; SEPTEMBER 20, 1996 sona Therapeutics, a drug develop- which they called human Toll. Within six one of these elements could cripple an in- CELL,

ment company in Dublin. months or so, Fernando Bazan and his fectious agent, which means that the or- HOFFMANN A. JULES AND REICHHART JEAN-MARC MICHAUT, LYDIA NICOLAS, EMMANUELLE LEMAITRE, BRUNO FROM IN

42 SCIENTIFIC AMERICAN JANUARY 2005 COPYRIGHT 2004 SCIENTIFIC AMERICAN, INC. ganisms cannot dodge TLRs by mutating against infection, multicellular organ- gaged, the TLRs prompt the cells to un- until these components are unrecogniz- isms might never have survived. leash particular suites of cytokines. able. And because so many of these ele- These protein messengers then recruit ments are shared by a variety of microbes, Storming the Castle additional macrophages, dendritic cells even as few as 10 TLRs can protect us the innate system was once and other immune cells to wall off and from virtually every known pathogen. thought to be no more elaborate than the nonspecifi cally attack the marauding mi- Innate immunity is not unique to hu- wall of a castle. The real action, research- crobe. At the same time, cytokines re- mans. In fact, the system is quite ancient. ers believed, occurred once the wall had leased by all these busy cells can produce Flies have an innate immune response, as been breached and the troops inside—the the classic symptoms of infection, includ- do starfi sh, water fl eas and almost every T and B cells—became engaged. We now ing fever and fl ulike feelings. organism that has been examined thus know that the castle wall is studded with Macrophages and dendritic cells that far. And many use TLRs as a trigger. The sentries—TLRs—that identify the invad- have chopped up a pathogen display nematode worm has one that allows it to er and sound the alarm to mobilize the pieces of it on their surface, along with sense and swim away from infectious troops and prepare the array of defenses other molecules indicating that a disease- bacteria. And plants are rife with TLRs. needed to fully combat the attack. TLRs, causing agent is present. This display, Tobacco has one called N protein that is in other words, unleash both the innate combined with the cytokines released in required for fi ghting tobacco mosaic vi- and adaptive systems. response to TLRs, ultimately activates B rus. The weed Arabidopsis has more The emerging picture looks some- and T cells that recognize those specifi c than 200. The fi rst Toll-like protein most thing like this. When a pathogen fi rst en- pieces, causing them—over the course of likely arose in a single-celled organism ters the body, one or more TLRs, such as several days—to proliferate and launch a that was a common ancestor of plants those on the surface of patrolling macro- powerful, highly focused attack on the and animals. Perhaps these molecules phages and dendritic cells, latch onto the particular invader. Without the priming even helped to facilitate our evolution. foreign molecules—for example, the LPS effect of TLRs, B and T cells would not Without an effi cient means of defense of gram-negative bacteria. Once en- become engaged and the body would not THE JOBS OF TOLL-LIKE RECEPTORS

Each Toll-like receptor can detect some essential component TLR4 of a broad class of disease-causing agents, and as a TLR4 group, TLRs can apparently recognize almost every TLR5 pathogen likely to cause infections. Different combinations appear in different kinds of cells, where the molecules act in pairs. Investigators have identiﬁ ed TLR6 10 human TLRs and know many of TLR2 Binds to Binds to LPS from ﬂ agellin in the the molecules they recognize gram-negative tails of motile (below). The function of bacteria bacteria TLR10 and the partners of TLR3, 5, 7, 8 and TLR2 9 are unknown. Binds to lipoteichoic acid TLR1 (a component of gram-positive bacteria)and to zymosan, produced by fungi

Binds to so-called Binds to uniquely bacterial CpG DNA from lipopeptides (lipid-protein Binds to single- bacteria or viruses Cell surface combinations) and stranded viral RNA to molecules called GPI-anchored proteins in parasites Binds to single- Compartment stranded viral RNA, for degrading such as in HIV pathogens TLR9 TLR8 Binds to double- stranded viral TLR7 RNA, such as in West Nile virus TLR3 TAMI TOLPA

www.sciam.com SCIENTIFIC AMERICAN 43 COPYRIGHT 2004 SCIENTIFIC AMERICAN, INC. be able to mount a full immune response. proteins that carry their message to the to activating an effective antibacterial Nor could the body retain any memory nucleus, much as a bucket brigade shut- response by the body. of previous infections. tles water to a fi re. All the TLRs, with the The realization that TLRs can detect Following the initial infection, exception of TLR3, hand off their signal different microbial products and help to enough memory T and B cells are left be- to an adapter protein called MyD88. tailor the immune response to thwart hind so that the body can deal more ef- Which other proteins participate in the the enemy is now overturning long-held fi ciently with the invader should it return. relay varies with the TLR: my laboratory assumptions that innate immunity is a This army of memory cells can act so studies Mal, a protein we discovered that static, undiscriminating barrier. It is, in quickly that infl ammation might not oc- helps to carry signals generated by TLR4 fact, a dynamic system that governs al- cur at all. Hence, the victim does not feel and TLR2. TLR4 also requires two oth- most every aspect of infl ammation and as ill and might not even notice the infec- er proteins—Tram and Trif—to relay the immunity. tion when it recurs. signal, whereas TLR3 relies on Trif Innate and adaptive immunity are alone. Shizuo Akira of Osaka University From Legionella to Lupus thus part of the same system for recog- in Japan has shown that mice engineered on recognizing the central role that nizing and eliminating microbes. The so that they do not produce some of these TLRs play in initiating immune respons- interplay between these two systems is intermediary signaling proteins do not es, investigators quickly began to suspect what makes our overall immune system respond to microbial products, suggest- that hobbled or overactive versions of so strong. ing that TLR-associated proteins could these receptors could contribute to many provide novel targets for new anti-in- infectious and immune-related disorders. Choose Your Weapon fl ammatory or antimicrobial agents. That hunch proved correct. Defects in in- to fully understand how TLRs Interaction with different sets of sig- nate immunity lead to greater susceptibil- control immune activity, immunologists naling proteins allows TLRs to activate ity to viruses and bacteria. People with an need to identify the molecules that relay different sets of genes that hone the cell’s underactive form of TLR4 are fi ve times signals from activated TLRs on the cell response to better match the type of as likely to have severe bacterial infec- surface to the nucleus, switching on pathogen being encountered. For exam- tions over a fi ve-year period than those genes that encode cytokines and other ple, TLR3 and TLR7 sense the presence with a normal TLR4. And people who immune activators. Many investigators of viruses. They then trigger a string of die from Legionnaire’s disease often har- are now pursuing this search intensive- molecular interactions that induce the bor a mutation in TLR5 that disables the ly, but already we have made some fas- production and release of interferon, the protein, compromising their innate im- cinating discoveries. major antiviral cytokine. TLR2, which mune response and rendering them un- We now know that TLRs, like many is activated by bacteria, stimulates the able to fi ght off the Legionella bacterium. receptors that reside on the cell surface, release of a blend of cytokines that does On the other hand, an overzealous im- enlist the help of a long line of signaling not include interferon but is more suited mune response can be equally destructive. In the U.S. and Europe alone, more than 400,000 people die annually from MECHNIKOV’S FLEAS sepsis, which stems from an overactive The discovery of Tolls and Toll-like immune response led by TLR4. receptors extends a line of research Other studies are pointing to roles for begun more than 100 years ago, when TLRs in autoimmune diseases such as Russian biologist Ilya Mechnikov systemic lupus erythematosus and rheu- essentially discovered innate immunity. matoid arthritis. Here TLRs might re- In the early 1880s Mechnikov plucked spond to products from damaged cells, some thorns from a tangerine tree and propagating an inappropriate infl amma- poked them into a starfi sh larva. The tory response and promoting a misguided next morning he saw that the thorns reaction by the adaptive immune system. were surrounded by mobile cells, which In lupus, for example, TLR9 has been he surmised were in the process of engulfi ng bacteria introduced along with MECHNIKOV was a character. Speaking of found to react to the body’s own DNA. the foreign bodies. He then discovered the era when he worked at the Pasteur Innate immunity and the TLRs could that water fl eas (Daphnia) exposed to Institute, his Nobel Prize biography notes, also play a part in heart disease. People “It is said of him that at this time he usually fungal spores mount a similar response. with a mutation in TLR4 appear to be wore overshoes in all weathers and carried This process of phagocytosis is a an umbrella, his pockets being overfull with less prone to developing cardiovascular cornerstone of innate immunity, and scientifi c papers, and that he always wore disease. Shutting down TLR4 could pro- its discovery earned Mechnikov a Nobel the same hat, and often, when he was tect the heart because infl ammation ap- Prize in 1908. excited, sat on it.” pears to contribute to the formation of

the plaques that clog coronary arteries. ARCHIVE/GETTYHULTON IMAGES

44 SCIENTIFIC AMERICAN JANUARY 2005 COPYRIGHT 2004 SCIENTIFIC AMERICAN, INC. TLRS AS DRUG TARGETS treat them more aggressively. If, for in- Agents that activate TLRs and thus enhance immune responses could increase stance, patients came to a clinic with a the effectiveness of vaccines or protect against infection. They might even prod bacterial infection and were found to the immune system to destroy tumors. In contrast, drugs that block TLR activity have a mutant TLR4, the doctor might might prove useful for dampening infl ammatory disorders. Drugs of both types bombard them with antibiotics or with are under study (below). agents that could somehow bolster their immune response to prevent the infec- DRUG TYPE EXAMPLES tion from doing lasting damage. TLR4 activator MPL, an allergy treatment and vaccine adjuvant (immune system Of course, a balance must be struck activator) from Corixa (Seattle), is in large-scale clinical trials between stimulating an immune re- TLR7 activator ANA245 (isatoribine), an antiviral agent from Anandys (San Diego), sponse that is suffi cient to clear a mi- is in early human trials for hepatitis C crobe and precipitating an infl ammatory response that will do more harm than TLR7 and TLR8 Imiquimod, a treatment for genital warts, basal cell skin cancer and good. Similarly, any medications that activator actinic keratosis from 3M (St. Paul, Minn.), is on the market aim to relieve infl ammation by quelling TLR9 activator ProMune, a vaccine adjuvant and treatment for melanoma skin TLR activity and cytokine release must cancer and non-Hodgkin’s lymphoma from Coley (Wellesley, Mass.), not, at the same time, undercut the is in large-scale clinical trials body’s defense against infection. TLR4 inhibitor E5564, an antisepsis drug from Eisai (Teaneck, N.J.), Anti-infl ammatory drugs that inter- is in early human trials fere with TNF-alpha, one of the cytokines produced as a result of TLR4 ac- General TLR RDP58, a drug for ulcerative colitis and Crohn’s disease from inhibitor Genzyme (Cambridge, Mass.), is entering large-scale clinical trials tivation, offer a cautionary tale. TNF- alpha produced during infection and General TLR OPN201, a drug for autoimmune disorders from Opsona Therapeutics inflammation can accumulate in the inhibitor (Dublin, Ireland), is being tested in animal models of infl ammation joints of patients with rheumatoid arthritis. The anti-infl ammatory compounds Manipulation of TLR4 might therefore activate TLR9, a receptor that recogniz- alleviate the arthritis, but some people be another approach to preventing or es a broad range of bacteria and viruses taking them wind up with tuberculosis. limiting this condition. and drives a robust immune response. The infection is probably latent, but rein- And TLRs are teaching us how to de- ing in the infl ammatory response can also Volume Control fend ourselves against biological weap- dampen the pathogen-specifi c responses many of the big pharmaceutical ons, such as poxviruses. A potential and allow the bacterium to reemerge. companies have an interest in using staple in the bioterrorist arsenal, these In short, TLRs are like the volume TLRs and their associated signaling pro- viruses can shut down TLRs and thereby knob on a stereo, balancing adaptive im- teins as targets for drugs that could treat avoid detection and elimination. In col- munity and infl ammation. Researchers infections and immune-related disor- laboration with Geoffrey L. Smith of and pharmaceutical companies are now ders. With the spread of antibiotic resis- Imperial College London, my lab found looking for ways to tweak these con- tance, the emergence of new and more that by removing the viral protein that trols, so they can curtail infl ammation virulent viruses, and the rising threat of disables TLRs, we could generate a without disabling immunity. bioterrorism, the need to come up with weakened virus that could serve as the Given that TLRs were unheard of fresh ways to help our bodies fi ght infec- basis of a vaccine unlikely to provoke an seven years ago, investigators have made tion is becoming more pressing. unintended fatal pox infection. enormous progress in understanding the Work on TLRs could, for example, Armed with an understanding of central role these proteins play in the guide the development of safer, more ef- TLRs and innate immunity, physicians body’s fi rst line of defense. Innate immu- fective vaccines. Most vaccines depend might be able to predict which patients nity, long shrouded in oblivion, has sud- on the inclusion of an adjuvant, a sub- will fare poorly during infection and denly become the belle of the ball. stance that kick-starts the infl ammatory response, which in turn pumps up the MORE TO EXPLORE ability of the adaptive system to generate Innate Immunity. Ruslan Medzhitov and Charles Janeway in New England Journal of Medicine, the desired memory cells. The adjuvant Vol. 343, No. 5, pages 338–344; August 3, 2000. used in most vaccines today does not Inferences, Questions and Possibilities in Toll-like Receptor Signaling. Bruce Beutler in Nature, Vol. 430, pages 257–263; July 8, 2004. provoke a full adaptive response; instead Toll-like Receptor Control of the Adaptive Immune Responses. Akiko Iwasaki and Ruslan it favors B cells over T cells. To elicit a Medzhitov in Nature Immunology, Vol. 5, No. 10, pages 987–995; October 2004. stronger response, several companies TLRs: Professor Mechnikov, Sit on Your Hat. L.A.J. O’Neill in Trends in Immunology, Vol. 25, No. 12, have set their sights on compounds that pages 687–693; December 2004.

www.sciam.com SCIENTIFIC AMERICAN 45 COPYRIGHT 2004 SCIENTIFIC AMERICAN, INC. COSMIC DOWNSIZING has occurred over the past 14 billion years as activity has shifted to smaller galaxies. In the ﬁ rst half of the universe’s lifetime, giant galaxies gave birth to prodigious numbers of stars and supermassive black holes that powered brilliant quasars (left). In the second half, activity in the giant galaxies slowed, but star formation and black hole building continued in medium-size galaxies (center). In the future, the main sites of cosmic activity will be dwarf galaxies holding only a few million stars each (right). CREDIT CREDIT

46 SCIENTIFIC AMERICAN JANUARY 2005 COPYRIGHT 2004 SCIENTIFIC AMERICAN, INC. themidlifeCRISIS of the COSMOS By Amy J. Barger Although it is not as active as it used to be, the universe is still forming stars and building black holes at an impressive pace CREDIT CREDIT

www.sciam.com SCIENTIFIC AMERICAN 47 COPYRIGHT 2004 SCIENTIFIC AMERICAN, INC. Until recently, most astronomers believed that the universe had entered a very boring middle age. discovered many tremendously massive oldest dating back to about one billion According to this paradigm, the early black holes still devouring the surround- years after the big bang. A more recent history of the universe—that is, until ing gas and dust. Furthermore, a more study, called the Hubble Ultra Deep about six billion years after the big thorough study of the light emitted by Field, has revealed even older galaxies. bang—was an era of cosmic fi reworks: galaxies of different ages has shown that Obtaining these deep-field images is galaxies collided and merged, powerful the star formation rate has not declined only the beginning, however. Astrono- black holes sucked in huge whirlpools of as steeply as once believed. mers want to understand how the oldest gas, and stars were born in unrivaled The emerging consensus is that the and most distant objects evolved into profusion. In the following eight billion early universe was dominated by a small present-day galaxies. It is somewhat like years, in contrast, galactic mergers be- number of giant galaxies containing co- learning how a human baby grows to be came much less common, the gargan- lossal black holes and prodigious bursts an adult. Connecting the present with tuan black holes went dormant, and star of star formation, whereas the present the past has become one of the domi- formation slowed to a fl icker. Many as- universe has a more dispersed nature— nant themes of modern astronomy. tronomers were convinced that they the creation of stars and the accretion of A major step in this direction is to were witnessing the end of cosmic his- material into black holes are now occur- determine the cosmic stratigraphy— tory and that the future held nothing but ring in a large number of medium-size which objects are in front and which are the relentless expansion of a becalmed and small galaxies. Essentially, we are more distant—among the thousands of and senescent universe. in the midst of a vast downsizing that is galaxies in a typical deep-fi eld image. In the past few years, however, new redistributing cosmic activity. The standard way to perform this task observations have made it clear that the is to obtain a spectrum of each galaxy reports of the universe’s demise have Deep-Field Images in the image and measure its redshift. been greatly exaggerated. With the ad- to piece together the history of Because of the universe’s expansion, the vent of new space observatories and new the cosmos, astronomers must first light from distant sources has been instruments on ground-based telescopes, make sense of the astounding multitude stretched, shifting its wavelength to- astronomers have detected violent activ- of objects they observe. Our most sensi- ward the red end of the spectrum. The ity occurring in nearby galaxies during tive optical views of the universe come more the light is shifted to the red, the the recent past. (The light from more dis- from the Hubble Space Telescope. In the farther away the source is and thus the tant galaxies takes longer to reach us, so Hubble Deep Field studies—10-day ex- older it is. For example, a redshift of one we observe these structures in an earlier posures of two tiny regions of the sky means that the wavelength has been stage of development.) By examining the observed through four different wave- stretched by 100 percent, that is, to x-rays emitted by the cores of these rela- length fi lters—researchers have found twice its original size. Light from an ob- tively close galaxies, researchers have thousands of distant galaxies, with the ject with this redshift was emitted about six billion years after the big bang, Middle-Aged Cosmos which is less than half the current age of Overview/ the universe. In fact, astronomers usu- ■ The early history of the universe was a turbulent era marked by galactic ally talk in terms of redshift rather than

collisions, huge bursts of star formation and the creation of extremely years, because redshift is what we mea- ) massive black holes. The falloff in cosmic activity since then has led many sure directly. astronomers to believe that the glory days of the universe are long gone. Obtaining redshifts is a practically ■ In recent years, though, researchers have found powerful black holes still foolproof technique for reconstructing

actively consuming gas in many nearby galaxies. New observations also cosmic history, but in the deepest of the pages preceding suggest that star formation has not dropped as steeply as once believed. deep-ﬁ eld images it is almost impossible ■ The results point to a cosmic downsizing: whereas the early universe was to measure redshifts for all the galaxies. dominated by a relatively small number of giant galaxies, activity in the One reason is the sheer number of galax- current universe is dispersed among a large number of smaller galaxies. ies in the image, but a more fundamental

problem is the intrinsic faintness of some ( KAMAJIAN T. ALFRED

As astronomers peer into the depths of space, they also ago, stars continued to form at a high rate, and black holes look back in time, because the light from distant objects continued to grow inside the galactic cores. In more recent takes longer to reach us. More than 10.5 billion years ago, times, star formation and black hole activity began to die tremendous galaxies collided and merged, triggering bursts down in the bigger galaxies; in the present-day universe, of star formation and the accretion of gas into supermassive most of the star formation takes place in smaller spiral and black holes. Between eight billion and 10.5 billion years irregular galaxies.

10.5 BILLION YEARS AGO

8 BILLION YEARS AGO

PRESENT

MILKY WAY

of the galaxies. The light from these dim nearby star-forming galaxy is equally pear in the ultraviolet waveband, and if objects arrives at a trickle of only one bright in all three wavebands. The in- the redshift is greater still, the galaxy photon per minute in each square centi- trinsic light from a star-forming galaxy will not be visible in the green waveband meter. And when observers take a spec- has a sharp cutoff just beyond the ultra- either. trum of the galaxy, the diffraction grat- violet waveband, at a wavelength of Thus, Cowie and Lilly could sepa- ing of the spectrograph disperses the about 912 angstroms. (The cutoff ap- rate star-forming galaxies into broad light over a large area on the detector, pears because the neutral hydrogen gas redshift intervals that roughly indicated rendering the signal even fainter at each in and around the galaxy absorbs radia- their ages. In 1996 Charles C. Steidel of wavelength. tion with shorter wavelengths.) Because the California Institute of Technology In the late 1980s a team led by Len- the light from distant galaxies is shifted and his collaborators used this tech- nox L. Cowie of the University of Ha- to the red, the cutoff moves to longer nique to isolate hundreds of ancient waii Institute for Astronomy and Simon wavelengths; if the redshift is great star-forming galaxies with redshifts of J. Lilly, now at the Swiss Federal Insti- enough, the galaxy’s light will not ap- about three, dating from about two bil- tute of Technology in Zurich, developed a novel approach to avoid the need for AMY J. BARGER studies the evolution of the universe by observing some of its oldest laborious redshift observations. The re- objects. She is an associate professor of astronomy at the University of Wisconsin–Mad- searchers observed regions of the sky ison and also holds an afﬁ liate graduate faculty appointment at the University of Hawaii with ﬁ lters that selected narrow wave- at Manoa. Barger earned her Ph.D. in astronomy in 1997 at the University of Cambridge, bands in the ultraviolet, green and red then did postdoctoral research at the University of Hawaii Institute for Astronomy. An

parts of the spectrum and then measured THE AUTHOR observational cosmologist, she has explored the high-redshift universe using the Chan- how bright the galaxies were in each of dra X-ray Observatory, the Hubble Space Telescope, and the telescopes on Kitt Peak in

ALFRED T. KAMAJIAN KAMAJIAN T. ALFRED the wavebands [see box on page 51]. A Arizona and on Mauna Kea in Hawaii.

www.sciam.com SCIENTIFIC AMERICAN 49 COPYRIGHT 2004 SCIENTIFIC AMERICAN, INC. frame ultraviolet light, researchers can cal telescopes cannot detect every source estimate the number of high-mass stars in the early universe. The more distant in the galaxy. a galaxy is, the more it suffers from cos- Because high-mass stars live for only mological redshifting, and at high a few tens of millions of years—a short enough redshifts, the galaxy’s rest- time by galactic standards—their num- frame ultraviolet and optical emissions ber closely tracks variations in the gal- will be stretched into the infrared part axy’s overall star formation rate. As the of the spectrum. Furthermore, stars pace of star creation slows, the number tend to reside in very dusty environ- of high-mass stars declines soon after- ments because of the detritus from su- ward because they die so quickly after pernova explosions and other processes. they are born. In our own Milky Way, The starlight heats up the dust grains, which is quite typical of nearby, massive which then reradiate this energy at far- spiral galaxies, the number of observed infrared wavelengths. For very distant EXTREMELY LUMINOUS GALAXIES in the early high-mass stars indicates that stars are sources, the light that is absorbed by universe have been discovered using the forming at a rate of a few solar masses a dust and reradiated into the far-infrared Submillimeter Common-User Bolometer Array (SCUBA) on the James Clerk Maxwell Telescope year. In high-redshift galaxies, however, is shifted by the expansion of the union Mauna Kea in Hawaii. The bright blob on the the rate of star formation is 10 times as verse to submillimeter wavelengths. left is believed to be an ancient dust- great. Therefore, a bright source of submilli- enshrouded galaxy that spawned stars at a When Cowie and Lilly calculated meter light is often a sign of intense star phenomenal rate, forming the equivalent of the star formation rates in all the galax- formation. more than 1,000 suns every year. ies they observed, they came to the re- Until recently, astronomers found it markable conclusion that the universe diffi cult to make submillimeter observa- lion years after the big bang. The re- underwent a veritable baby boom at a tions with ground-based telescopes, searchers confi rmed many of the esti- redshift of about one. In 1996 Piero Ma- partly because water vapor in the atmo- mated redshifts by obtaining very deep dau, now at the University of California sphere absorbs signals of that wave- spectra of the galaxies with the power- at Santa Cruz, put the technique to work length. But those diffi culties were eased ful 10-meter Keck telescope on Mauna on the Hubble Deep Field North data, with the introduction of the Submilli- Kea in Hawaii. which were ideal for this approach be- meter Common-User Bolometer Array New observations make it clear that reports of the UNIVERSE’S DEMISE have been greatly exaggerated.

Once the redshifts of the galaxies cause of the very precise intensity mea- (SCUBA), a camera that was installed have been measured, we can begin to surements in four wavebands. Madau on the James Clerk Maxwell Telescope reconstruct the history of star forma- combined his results with those from on Mauna Kea in 1997. (Located at a

tion. We know from observations of existing lower-redshift optical observa- height of four kilometers above sea lev- James Clerk Maxwell Telescope nearby galaxies that a small number of tions to reﬁ ne the estimates of the star el, the observatory is above 97 percent high-mass stars and a larger number of formation history of the universe. He of the water in the atmosphere.) Several low-mass stars usually form at the same inferred that the rate of star formation teams of researchers, one of which I led, time. For every 20 sunlike stars that are must have peaked when the universe used SCUBA to directly image regions born, only one 10-solar-mass star (that was about four billion to six billion of the sky with sufﬁ cient sensitivity and is, a star with a mass 10 times as great years old. This result led many astrono- area coverage to discover distant, excep- as the sun’s) is created. High-mass stars mers to conclude that the universe’s best tionally luminous dust-obscured sourc- emit ultraviolet and blue light, whereas days were far behind it. es. Because the resolution is fairly low-mass stars emit yellow and red coarse, the galaxies have a bloblike ap- light. If the redshift of a distant galaxy An Absorbing Tale pearance [see illustration above]. They is known, astronomers can determine although madau’s analysis of are also relatively rare—even after many the galaxy’s intrinsic spectrum (also star formation history was an impor- hours of exposure, few sources ap- called the rest-frame spectrum). Then, tant milestone, it was only a small part peared on each SCUBA image—but they

by measuring the total amount of rest- of the story. Galaxy surveys using opti- are among the most luminous galaxies A. J. BARGER, L. L. COWIE, D. B. SANDERS, E. FULTON ET AL.

To efficiently detect the 5 Ultraviolet Green waveband Red waveband oldest galaxies in a survey waveband field, astronomers have developed a technique 4 employing filters that select wavebands in the 3 ultraviolet, green and red parts of the spectrum. Because of the expansion of 2 Radiation from the universe, the light from high-redshift galaxy the oldest galaxies has been shifted toward the red end; Relative Strength of Signal 1 the graph (top) shows how a relatively high redshift (about three) can push the 3,000 4,000 5,000 6,000 7,000 8,000 radiation from a distant Wavelength (angstroms) galaxy out of the ultraviolet waveband. As a result, the ancient galaxies appear in images made with the red and green filters but not in images made with the ultraviolet filter (bottom). )

images in the universe. It is sobering to realize more quasars several billion years after star formation, was more vigorous in ( that before SCUBA became available, the big bang than there are active galac- the distant past, a third sign that we live we did not even know that these power- tic nuclei in the present-day universe. in relatively boring times. ful, distant systems existed! Their star Because the supermassive black holes This scenario, however, is incom- formation rates are hundreds of times that powered the distant quasar activity plete. By combining x-ray and visible- greater than those of present-day galax- cannot be destroyed, astronomers pre- light observations, astronomers are now ies, another indication that the universe sumed that many nearby galaxies must revisiting the conclusion that the vast used to be much more exciting than it is contain dead quasars—black holes that majority of quasars died out long ago. now. have exhausted their fuel supply. X-rays are important because, unlike California Institute of Technology of Institute California Finding all this previously hidden These dormant supermassive black visible light, they can pass through the star formation was revolutionary, but holes have indeed been detected through gas and dust surrounding hidden black might the universe be covering up other their gravitational inﬂ uence. Stars and holes. But x-rays are blocked by the violent activity? For example, gas and gas continue to orbit around the holes earth’s atmosphere, so researchers must dust within galaxies could also be ob- even though little material is swirling rely on space telescopes such as the scuring the radiation emitted by the into them. In fact, a nearly dormant Chandra and XMM/Newton X-ray ob- disks of material whirling around super- black hole resides at the center of the servatories to detect black hole activity massive black holes (those weighing as Milky Way. Together these results led [see “The Cosmic Reality Check,” by

); COURTESY OF CHARLES C. STEIDEL much as billions of suns). These disks scientists to develop a scenario: most su- Günther Hasinger and Roberto Gilli; are believed to be the power sources of permassive black holes formed during Scientiﬁ c American, March 2002]. graph quasars, the prodigiously luminous ob- the quasar era, consumed all the mate- In 2000 a team consisting of Cowie, jects found at high redshifts, as well as rial surrounding them in a violent ﬁ t of Richard F. Mushotzky of the NASA the active nuclei at the centers of many growth and then disappeared from opti- Goddard Space Flight Center, Eric A. nearby galaxies. Optical studies in the cal observations once their fuel supply Richards, then at Arizona State Univer-

TOMMY MOORMAN ( MOORMAN TOMMY 1980s suggested that there were far ran out. In short, quasar activity, like sity, and I used the Subaru telescope at

www.sciam.com SCIENTIFIC AMERICAN 51 COPYRIGHT 2004 SCIENTIFIC AMERICAN, INC. Star-forming galaxies have also un- dergone a cosmic downsizing. Although some nearby galaxies are just as extravagant in their star-forming habits as the extremely luminous, dust-obscured galaxies found in the SCUBA images, the density of ultraluminous galaxies in the present-day universe is more than 400 times lower than their density in the distant universe. Again, however, smaller galaxies have taken up some of the slack. A team consisting of Cowie, Gil- lian Wilson, now at NASA’s Infrared Processing and Analysis Center, Doug J. Burke, now at the Harvard-Smithson- ian Center for Astrophysics, and I has refi ned the estimates of the universe’s luminosity density by studying high- quality images produced with a wide X-RAY VISION can be used to fi nd hidden black holes. The Chandra X-ray Observatory detected range of fi lters and performing a com- many black holes in its Deep Field North survey (left). Some were ancient, powering brilliant quasars that fl ourished just a few billion years after the big bang (top right). But others lurked in plete spectroscopic follow-up. We found the centers of relatively nearby galaxies, still generating x-rays in the modern era (bottom right). that the luminosity density of optical and ultraviolet light has not changed all Mauna Kea to identify optical counter- that Chandra detected are more moder- that much with cosmic time. Although parts to 20 x-ray sources found by ate eaters and thus radiate less intensely. the overall star formation rate has Chandra in a survey fi eld. We then em- Scientists have not yet determined what dropped in the second half of the uni- ployed the 10-meter Keck telescope to mechanism is responsible for this vastly verse’s lifetime because the monstrous ); obtain the spectra of these objects. different behavior. One possibility is dusty galaxies are no longer bursting Our result was quite unexpected: that the present-day black holes have with stars, the population of small, many of the active supermassive black less gas to consume. Nearby galaxies nearby star-forming galaxies is so nu- Chandra image holes detected by Chandra reside in rel- undergo fewer collisions than the dis- merous that the density of optical and (

atively nearby, luminous galaxies. Mod- tant, ancient galaxies did, and such col- ultraviolet light is declining rather grad- ) elers of the cosmic x-ray background lisions could drive material into the su- ually. This result gives us a much more had predicted the existence of a large permassive black holes at the galactic optimistic outlook on the continuing population of obscured supermassive centers. health of the universe. optical images optical black holes, but they had not expected Chandra had yet another secret to re- ( them to be so close at hand! Moreover, veal: although the moderate x-ray sourc- Middle-Aged Vigor the optical spectra of many of these gal- es were much less luminous than the qua- the emerging picture of contin- axies showed absolutely no evidence of sars—generating as little as 1 percent of ued vigor ﬁ ts well with cosmological NASA/Pennsylvania State University black hole activity; without the x-ray the radiation emitted by their older coun- theory. New computer simulations sug- observations, astronomers could never terparts—when we added up the light gest that the shift from a universe dom- have discovered the supermassive black produced by all the moderate sources in inated by a few large and powerful gal- holes lurking in their cores. recent times, we found the amount to be axies to a universe filled with many This research suggests that not all about one tenth of that produced by the smaller and meeker galaxies may be a supermassive black holes were formed quasars in early times. The only way this direct consequence of cosmic expan- in the quasar era. These mighty objects result could arise is if there are many sion. As the universe expands, galaxies have apparently been assembling from more moderate black holes active now become more separated and mergers be- NASA/Great Observatories Origins Deep Survey Deep Origins Observatories NASA/Great the earliest times until the present. The than there were quasars active in the come rarer. Furthermore, as the gas sur- supermassive black holes that are still past. In other words, the contents of the rounding galaxies grows more diffuse, active, however, do not exhibit the same universe have transitioned from a small it becomes easier to heat. Because hot behavioral patterns as the distant qua- number of bright objects to a large num- gas is more energetic than cold gas, it sars. Quasars are voracious consumers, ber of dimmer ones. Even though super- does not gravitationally collapse as greedily gobbling up the material massive black holes are now being built readily into the galaxy’s potential well. around them at an enormous rate. In smaller and cheaper, their combined ef- Fabrizio Nicastro of the Harvard-

contrast, most of the nearby sources fect is still potent. Smithsonian Center for Astrophysics GARMIRE ET AL. P. BRANDT, G. ALEXANDER, N. M. BAUER, E. D. W. F. A. J. BARGER AND M. GIAVALISCO

52 SCIENTIFIC AMERICAN JANUARY 2005 COPYRIGHT 2004 SCIENTIFIC AMERICAN, INC. and his co-workers have recently detect- collaborators detected the presence of serve the explosions in the gamma-ray, ed a warm intergalactic fog through its carbon monoxide in the emission from x-ray, ultraviolet and optical wave- absorption of ultraviolet light and x- one of these quasars; because carbon lengths. By measuring the spectra of the rays from distant quasars and active ga- and oxygen could have been created gamma-ray bursts and their afterglows, lactic nuclei. This warm fog surrounds only from the thermonuclear reactions the Swift satellite could provide scien- our galaxy in every direction and is part in stars, this discovery suggests that a tists with a much better understanding of the Local Group of galaxies, which signifi cant amount of star formation oc- of how collapsing stars could have start- includes the Milky Way, Andromeda curred in the universe’s fi rst several hun- ed the growth of supermassive black and 30 smaller galaxies. Most likely this dred million years. Recent results from holes in the early universe. gaseous material was left over from the the Wilkinson Microwave Anisotropy In comic books, Superman looked galaxy formation process but is too Probe, a satellite that studies the cosmic through walls with his x-ray vision. As- warm to permit further galaxy forma- background radiation, also indicate that tronomers have now acquired a similar tion to take place. star formation began just 200 million ability with the Chandra and XMM/ Small galaxies may lie in cooler en- years after the big bang. Newton observatories and are making vironments because they may not have Furthermore, computer simulations good use of it to peer deep into the dust- heated their surrounding regions of gas have shown that the fi rst stars were most enshrouded regions of the universe. to the same extent that the big galaxies likely hundreds of times as massive as What is being revealed is a dramatic did through supernova explosions and the sun. Such stars would have burned transition from the mighty to the meek. quasar energy. Also, the small galaxies so brightly that they would have run out The giant star-forming galaxies and vo- may have consumed less of their sur- of fuel in just a few tens of millions of racious black holes of the universe’s rounding material, allowing them to years; then the heaviest stars would have past are now moribund. A few billion What is being revealed is a dramatic transition from the MIGHTY TO THE MEEK. Dwarf galaxies will become the PRIMARY HOT SPOTS of star formation. continue their more modest lifestyles to collapsed to black holes, which could years from now, the smaller galaxies the present day. In contrast, the larger have formed the seeds of the supermas- that are active today will have con- and more profl igate galaxies have ex- sive black holes that powered the fi rst sumed much of their fuel, and the total hausted their resources and are no lon- quasars. This explanation for the early cosmic output of radiation will decline ger able to collect more from their envi- appearance of quasars may be bolstered dramatically. Even our own Milky Way ronments. Ongoing observational stud- by the further study of gamma-ray will someday face this same fate. As the ies of the gaseous properties of small, bursts, which are believed to result from cosmic downsizing continues, the dwarf nearby galaxies may reveal how they in- the collapse of very massive stars into galaxies—which hold only a few mil- teract with their environments and thus black holes. Because gamma-ray bursts lion stars each but are the most numer- provide a key to understanding galactic are the most powerful explosions in the ous type of galaxy in the universe—will evolution. universe since the big bang, astronomers become the primary hot spots of star But a crucial part of the puzzle re- can detect them at very great distances. formation. Inevitably, though, the uni- mains unsolved: How did the universe This past November, NASA was expect- verse will darken, and its only contents form monster quasars so early in its his- ed to launch the Swift Gamma-Ray will be the fossils of galaxies from its tory? The Sloan Digital Sky Survey, a Burst Mission, a $250-million satellite glorious past. Old galaxies never die, major astronomical project to map one with three telescopes designed to ob- they just fade away. quarter of the entire sky and measure distances to more than a million remote MORE TO EXPLORE objects, has discovered quasars that ex- Star Formation History since z = 1 as Inferred from Rest-Frame Ultraviolet Luminosity isted when the universe was only one Density Evolution. Gillian Wilson et al. in Astronomical Journal, Vol. 124, pages 1258–1265; September 2002. Available online at www.arxiv.org/abs/astro-ph/0203168 sixteenth of its present age, about 800 The Cosmic Evolution of Hard X-ray Selected Active Galactic Nuclei. Amy J. Barger et al. in million years after the big bang. In 2003 Astronomical Journal (in press). Available online at www.arxiv.org/abs/astro-ph/0410527 Fabian Walter, then at the National Ra- Supermassive Black Holes in the Distant Universe. Edited by Amy J. Barger. Astrophysics and dio Astronomy Observatory, and his Space Science Library, Vol. 308. Springer, 2004. www.sciam.com SCIENTIFIC AMERICAN 53 COPYRIGHT 2004 SCIENTIFIC AMERICAN, INC. COPYRIGHT 2004 SCIENTIFIC AMERICAN, INC. Digital gadgets demand ever more of our attention with their rude and thoughtless interruptions. Engineers are now testing computers, phones and cars that sense ! when you’re busy and spare you from distraction CCONSIDERATEONSIDERATE CCOMPUTINGOMPUTING By W. Wayt Gibbs

“YOUR BATTERY IS NOW FULLY CHARGED,” ANNOUNCED THE LAPTOP COMPUTER to its owner, Donald A. Norman, with enthusiasm—perhaps even a hint of pride?—in its syn- thetic voice. Norman, a chief advocate of the notion that computers and appliances ought to be

programmed with something akin to To be sure, distractions and multi- even refrigerators and picture frames— emotions, might normally have smiled at tasking are hardly new to the human because these things make life more con- the statement. Instead he blushed—and condition. “A complicated life, continu- venient and keep us available to those we no doubt wished that his computer could ally interrupted by competing requests care about. So although we could simply share his embarrassment. For at that for attention, is as old as procreation,” turn off the phones, close the e-mail pro- moment, Norman was onstage at a dais, laughs Ted Selker of the Massachusetts gram, and shut the offi ce door when it is having addressed a conference room of Institute of Technology Media Lab. But time for a meeting or a stretch of concen- cognitive scientists and computer re- increasingly, it is not just our kids pull- trated work, we usually don’t. We just searchers, and his Powerbook was still ing us three ways at once; it is also a re- endure the consequences. plugged into the public address system. lentless barrage of e-mail, alerts, alarms, “We take major productivity hits Many in the audience chuckled at the au- calls, instant messages and automated with each interruption,” says Rosalind tomated faux pas and shook their heads. notifi cations, none of them coordinated Picard, a cognitive scientist at the M.I.T. The moderator, fl ustered, shot Norman and all of them oblivious to whether we Media Lab. People juggle the myriad de- a less than sympathetic look. are busy—or even present. “It’s ridicu- mands of work and daily life by main- And yet we’ve all been there. Our cell lous that my own computer can’t fi gure taining a mental list of tasks to be done. phones ring during movies. Telemarket- out whether I’m in front of it, but a pub- An interruption of just 15 seconds causes ers interrupt our dinners with friends. lic toilet can,” exclaims Roel Vertegaal most people to lose part of that to-do Our laptops throw up screensavers in of Queen’s University in Ontario. list, according to experiments by Gilles the middle of presentations. “You’ve got Humanity has connected itself O. Einstein of Furman University. mail!” derails our train of thought just through roughly three billion networked Numerous studies have shown that

PETER HOEY PETER as we get in the groove. telephones, computers, trafﬁ c lights— when people are unexpectedly interrupt-

www.sciam.com SCIENTIFIC AMERICAN 55 COPYRIGHT 2004 SCIENTIFIC AMERICAN, INC. and interns at work. They videotaped “It’s ridiculous that my own computer the subjects and periodically had them rate their “interruptibility.” The amount can’t fi gure out whether I’m in front of it, of time the workers spent in leave-me- but a public toilet can.” alone mode varied from person to per- ! son and day to day, ranging from 10 to 51 percent. On average, the subjects ed, they not only work less effi ciently but computer science and raises issues of pri- wanted to work without interruption also make more mistakes. “It seems to vacy, complexity or reliability. Never- about one third of the time. In studies of add cumulatively to a feeling of frustra- theless, “attentive” computing systems Microsoft employees, Horvitz has simi- tion,” Picard reports, and that stress re- have begun appearing in newer Volvos larly found that they typically spend sponse makes it hard to regain focus. It [see box on opposite page], and IBM has more than 65 percent of their day in a isn’t merely a matter of productivity and introduced Websphere communications state of low attention. the pace of life. For pilots, drivers, sol- software with a basic busyness sense. Today’s phones and computers, diers and doctors, errors of inattention Microsoft has been running extensive which naively assume that the user is can be downright dangerous. in-house tests of a much more sophisti- never too busy to take a call, read an e- “If we could just give our computers cated system since 2003. Within a few mail, or click “OK” on an alert box, thus and phones some understanding of the years, companies may be able to offer are probably correct about two thirds of limits of human attention and memory, every offi ce worker a software version time. (Hudson and Horvitz acknowl- it would make them seem a lot more of the personal receptionist that only edge, however, that it is not yet clear how thoughtful and courteous,” says Eric corner-suite executives enjoy today. well these figures generalize to other Horvitz of Microsoft Research. Horvitz, But if such an offer should land in jobs.) To be useful, then, considerate sys- Vertegaal, Selker and Picard are among your inbox, be sure to read the fi ne print tems will have to be more than 65 per- a small but growing number of research- before you sign. An attentive system, by cent accurate in sensing when their users ers trying to teach computers, phones, defi nition, is one that is always watch- are near their cognitive limits. cars and other gadgets to behave less like ing. That considerate computer may Fortunately, this doesn’t seem to re- egocentric oafs and more like consider- come to know more about your work quire strapping someone into a heart ate colleagues. habits than you do. monitor or a brain scanner. Fogarty and To do this, the machines need new his collaborators have found that simply skills of three kinds: sensing, reasoning Minding Your Busyness using a microphone to detect whether and communicating. First a system must most people aren’t as busy as anyone is talking within earshot would sense or infer where its owner is and they think they are, which is why we can raise accuracy to 76 percent. That is as what he or she is doing. Next it must usually tolerate interruptions from our good as the human judgment of co- weigh the value of the messages it wants inconsiderate electronic paraphernalia. workers who viewed videotapes of the to convey against the cost of the disrup- James Fogarty and Scott E. Hudson of subjects and guessed when they were un- tion. Then it has to choose the best mode Carnegie Mellon University recently interruptible. When Fogarty’s group en- and time to interject. teamed up with Jennifer Lai of IBM Re- hanced the software to detect not only Each of these pushes the limits of search to study 10 managers, researchers conversations but also mouse movement, keyboard activity and the applications Sensing Attention running on machines, the system’s ac- Overview/ curacy climbed to 87 percent for the two ■ Computers continue to grow cheaper, more powerful and more pervasive. managers. Curiously, it rose only to 77 Human attention, in contrast, is a scarce and fi xed resource. As we spend percent for the fi ve scientists, perhaps more of our time surrounded by “smart” devices, their productivity-sapping, because they are a chattier bunch. stress-inducing interruptions increasingly detract from their value. Bestcom/Enhanced Telephony, a Mi- ■ Researchers at corporate and academic labs have developed several powerful crosoft prototype based on Horvitz’s techniques that enable computerized machines to estimate their user’s work, digs a little deeper into each user’s cognitive load and focus of attention. computer to fi nd clues about what they ■ Engineers are testing prototype systems that can automatically prioritize, are up to. Microsoft launched an inter- reschedule or forward incoming phone calls and digital messages, much as a nal beta test of the system in mid-2003. personal receptionist might. Similar attention-sensing technology has begun By last October, Horvitz says, about to appear in cars and may lead to more “considerate” everyday appliances. 3,800 people were using the system to ■ Monitoring a person’s attention requires sophisticated reasoning based on infi eld their incoming phone calls. depth surveillance. The work thus raises issues of privacy and reliability. Horvitz himself is one of those tes- ters, and while we talk in his offi ce in

56 SCIENTIFIC AMERICAN JANUARY 2005 COPYRIGHT 2004 SCIENTIFIC AMERICAN, INC. Attentive Autos c irst the eyelids droop, then the head begins to bob. The car drifts out of its Flane, then jerks back erratically. The signs of a drowsy or distracted driver are not hard to spot, but one must look for them. Many vehicles soon will. The U.S. National Highway Traffi c a b Safety Administration (NHTSA) fi gures that d 20 to 30 percent of crashes reported to the police—about 1.5 million every year— d result at least in part from inattentive c drivers. Technology contributes to this problem, cluttering up the cabin with e phones, DVD players, touch-screen maps and other doodads. Now technology of a different kind may help to solve it. In 2003 Volvo added an attention management system to its S40 sedans. e Sensors pick up steering actions, accelerator position and other vehicle “CONSIDERATE CARS” of the future could combine a variety of systems to sense the dynamics. They feed into a computer, attention level of the driver and prevent dangerous distractions. In this example, Alice is which looks for evidence of swerving, driving at high speed in heavy traffi c, but her concentration is interrupted by a rambunctious daughter. The car ahead has begun to brake as it enters a construction overtaking or hard braking. When it zone. But at the same moment, Alice’s mobile phone receives a call, and the onboard notices such demanding maneuvers, the navigation system decides to alert her to an upcoming exit. system suppresses nonsafety-critical messages from the onboard phone, a MIND THE GAP: A short-range radar mounted on the front of the car notices that navigation system, warning lights, and so the vehicle ahead is getting closer. The adaptive cruise-control system on. In June, Motorola and DaimlerChrysler automatically eases off the gas and gently applies the brake to maintain separation. demonstrated a minivan outfi tted with a Such systems are already available on certain luxury cars. similar system. More recently, Volvo has b I T ’ S A S I G N : A forward-looking video camera watches the road. An onboard been testing cameras that can detect computer continually scans the video for lane markers and road signs. It recognizes drowsy eyelids and suspicious lane the construction warning ahead and raises the car’s estimate of the current burden crossings [see illustration at right]. on the driver’s attention. Alexander Zelinsky and his co-workers at the Australian Last March the European Union National University have demonstrated such sign-reading systems. launched a four-year, €12.5-million WATCHING THE WATCHER: LEDs on the visor shine invisible infrared light into project to develop industrywide standards c Alice’s eyes; a small infrared camera picks up the refl ections from her pupils and for adaptive driver-vehicle interfaces by deduces the direction of her gaze. If the driver takes her eyes off the road or shows 2008. Engineers must still solve many signs of drowsiness, an icon in the instrument panel lights up, and the car goes on tricky issues. high alert. It vibrates the steering wheel if needed to rouse her. Zelinsky started a “Liability is a major stumbling block in company, Seeing Machines, to commercialize such gaze monitors, and Volvo and the U.S.,” observes Trent Victor, who others have tested them in cars and trucks. designs driver awareness systems for d EYES ON THE ROAD: Because Alice is looking away at a moment when the Volvo. Automakers must be certain the demands on her attention are high, the system emits an alert sound through the car computer will not make a bad situation speakers and fl ashes a sequence of lights on the dash that draws her attention back worse, even if the driver uses it to the car ahead. Tests by Volvo have shown this method to be effective. improperly. Indeed, it seems inevitable that as the e NOT NOW, PLEASE: The onboard computer has a model of the driver’s abilities system adapts to drivers, drivers will adapt and is always monitoring the cognitive load, so it knows that now is a bad time for a right back. “There are people today who use phone call or a navigational alert. The computer turns off the ringer on the cell phone and instead lights an unobtrusive “incoming message” button on the steering wheel the rumble strips [which buzz when a car that Alice can press to take the call when it is safe to do so. The car likewise lights approaches the edge of a road] as a way to another button to let her know that the navigation system has an instruction for her. help them watch TV,” Trent says. —W.W.G. Chrysler has built such gentle notifi cation devices into some of its prototype cars. PETER HOEY PETER

Notiﬁ cation Platform, a prototype system developed by Horvitz reading e-mail (2) or packing for a business trip (3). One part and his co-workers at Microsoft, performs triage on incoming of the system estimates the value of the message and how communications much as a receptionist would. The system, that value decays with time. A second part uses sensors and which runs on a central server, analyzes messages to decide a statistical model to guess the focus and intensity of Alice’s whether, when and how to notify the recipient of their arrival. It attention, what devices she is using, how likely she is to see the would handle the same e-mail message to Alice from her boss message without an alert, and how these variables will change differently if she were conducting a job interview (scenario 1), in the future. A third part decides what kind of alert to issue.

ERIC HORVITZ (left) pioneered the use of sensors and statistical models (above) to build attention-aware communications systems.

Redmond, Wash., Bestcom silently han- Most large companies already use vacy tool into Bestcom from the begin- ) dles one call after another. First it checks computerized phone systems and stan- ning,” Horvitz emphasizes, “so users whether the caller is listed in his address dard calendar and contact management can control who is allowed to see the diagram book, the company directory, or its log software, so tapping into those “sen- various kinds of information it collects of people he has called recently. Triangu- sors” should be straightforward. Not all about them.” lating these sources, it tries to deduce employees will like the idea of having a their relationship. Family members, su- microphone on all the time in their of- Watching the Watcher pervisors and people he called earlier ﬁ ce, however, nor will everyone want to as digital cameras fall in price, ); JEN CHRISTIANSEN ( today ring through. Others see a mes- expose their datebook to some program that information may come to include sage on their computer that he is in a they do not ultimately control. More- video. With a simple $20 webcam, Hor- scenarios meeting and won’t be available until 3 over, some managers might be tempted vitz’s software can tell when a person is P.M. The system scans Horvitz’s and the to equate a “state of low attention” with in view and whether she is alone or in a caller’s calendar and offers to reschedule “goofing off” and punish those who meeting. Fancier cameras can use the

the call at a time that is open for both. seem insufﬁ ciently busy. eyes as a window to the mind and per- ( HOEY PETER ); Some callers choose that option; others The researchers seem to appreciate haps extend the reach of considerate leave voice mail. E-mail messages get a these risks. Hudson argues that an atten- computers into the home.

similar screening. When Horvitz is out tive system should not record audio, key- Vertegaal has ﬁ lled the Human Me- photographs of the ofﬁ ce, Bestcom automatically of- strokes or the like but simply analyze the dia Lab at Queen’s University with ev- fers to forward selected callers to his cell data streams and discard them after log- eryday appliances that know when you phone—unless his calendar and other ging “conversation in progress,” “typing are looking at them. “When I say ‘on,’

evidence suggest that he is in a meeting. detected,” and so on. “We built a pri- the lamp over there doesn’t do any- ( ARMSTRONG KC

Camera

Microphone

Task completion Ambient acoustics

URGENCY Deadline status CLASSIFIER Interaction with computer consults its database to determine the relationship between Date and time Focus of attention Conversation in progress the sender and recipient and their communication history. A linguistic analyzer scans the text for times, dates and key words. Schedule Location Gaze direction The classiﬁ er “stamps” the message with a dollar value that can fall as the communication BAYESIAN STATISTICAL MODEL grows stale. fuses information from many sources Wireless signal (highlighted objects) to infer Alice’s current focus of attention.

SCENARIO 1 SCENARIO 2 SCENARIO 3 The system also estimates the cost 8 8 8 of interrupting Alice now and in the near future. It alerts her to the 4 4 4 message only when the cost of Cost ($) Cost Cost ($) Cost Cost ($) Cost a distraction falls below the value 0 0 0 of a notiﬁ cation (arrows). 0 10 20 30 40 50 60 0 10 20 30 40 50 60 0 10 20 30 40 50 60 Delay (minutes) Delay (minutes) Delay (minutes)

Focus of attention User preferences

Value of notification Notification method Cost of notification

DECISION MODEL surveys the devices available to Predicted usefulness Alice and performs a cost-beneﬁ t analysis to determine if, when and how to signal her that this message has arrived.

SCENARIO 1 SCENARIO 2 SCENARIO 3

The Notiﬁ cation Platform adds the e-mail The system senses that Alice is at her PC and The system matches the subject of the e-mail from Alice’s boss to her inbox but does not is composing an e-mail. It waits for her to ﬁ nish to an entry in Alice’s schedule for today and notify her about the message until one hour writing, then chimes and displays a small alert assigns it highest priority. The e-mail is later, after her appointment with the job box in the corner of the screen, notifying her forwarded to her “considerate” cell phone, candidate has ended. about the message from her boss. which signals her with an urgent ring tone.

Roel Vertegaal (left) and his students at Queen’s University in Kingston, Ontario, have been enhancing televisions, phones, computers and video-conferencing systems with the ability to sense human eye contact. They have also put the technology to artistic use in AuraMirror (right). Hidden infrared lights, cameras and a computer transform a large monitor into a virtual magic mirror that superimposes nebulous “auras” over the images of people in front of it. The blobs extend outward and merge when two observers look at each other, giving visible form to an intangible human connection (far right).

“Eye contact is the most accurate measure of attention ! that we have. But it’s not perfect by any means.”

thing,” Vertegaal says, pointing over his that information via a wireless link to particular piece of information. Both shoulder. He turns to face the object. the cell phone in his pocket, which then approaches must face the bugbear of “On,” he says. LEDs mounted on a switches from ring mode to vibrate. complexity. small circuit board stuck to the lamp Although the technology is steadily If the system is limited to following a shoot invisible infrared light into his pu- improving, gaze detectors are still too few rules, users can predict exactly how pils. The light refl ects off his retinas, and expensive, bulky, ugly and unreliable for it will treat a given message. Many e-mail an infrared camera on the board picks everyday use. “Eye contact is the most programs, for example, manage spam by up two bright spots in the image, one accurate measure of attention that we maintaining lists of known spammers from each eye. A processor does some have—about 80 percent accurate in con- and of legitimate contacts. When each quick pattern and speech recognition, versational settings,” Vertegaal says. e-mail arrives, its sender is compared and the lamp switches on. “But it’s not perfect by any means.” against both lists and either deleted or Gaze detection can endow quotidian Attentive appliances are mere parlor delivered. Such systems are simple and machines with seemingly magical be- tricks, moreover, when they act indepen- clear—but infamously inaccurate. havior. Vertegaal answers a ringing tele- dently. The real payoff will only come Spam fi lters and network fi rewalls phone by looking at it and saying “Hel- from larger, smarter systems that can improved signifi cantly when they began lo.” When he stops talking and turns both divine the focus of our attention to rely on statistical models, called Bayes- away from the phone, it hangs up. The and moderate our conversation with all ian networks, that are built by machine- TV in the lab pauses a DVD or mutes the our personal machines. Doing that reli- learning algorithms. The user gives the sound on a broadcast show whenever it ably will require a nice bit of reasoning. algorithm many examples of desirable notices that there are no longer any eyes messages and also some counterexam- watching it. Some of Vertegaal’s students Trusting the Black Box ples of undesired traffi c. “The software walk around with eye-contact sensors broadly speaking, computers can identifi es all the variables that infl uence on their hat or glasses. When the wearer use two techniques—rules or models— the property that you are interested in enters a conversation, the sensor passes to decide when and how to transmit a [for example, not spam], then searches over all feasible relationships among those variables to fi nd the model that is “Artifi cial intelligence couldn’t deliver the most predictive,” Horvitz explains. Bayesian networks can be eerily ac- personal secretary. I’m pretty sure we can curate. “They use probabilities, so they deliver a personal receptionist.” are wise in the sense that they know that

! they can’t know everything,” Horvitz ARMSTRONG KC

60 SCIENTIFIC AMERICAN JANUARY 2005 COPYRIGHT 2004 SCIENTIFIC AMERICAN, INC. elaborates. “That allows them to cap- That would be welcome, but will No comparable studies have yet been ture subtle behaviors that would require considerate computing really reduce in- done in the offi ce environment, however. thousands of strict rules.” In January he terruptions and boost productivity? At Even with Bestcom diverting callers to plans to present the results of a fi eld trial least for certain specialized tasks, the voice mail and squelching e-mail alerts, of a model trained on 559 past appoint- answer is: unquestionably. Horvitz was interrupted 14 times in the ments taken from a manager’s datebook. Consider Lockheed Martin’s HAIL- course of our fi ve-hour interview. Two When challenged with 100 calendar en- SS (Human Alerting and Interruption fi re alarms, a FedEx deliveryman and tries it had never seen, the model cor- Logistics-Surface Ship) system. In much numerous colleagues poking their head rectly predicted whether the manager the way that Bestcom interposes itself into the offi ce were merely examples of would attend the meeting 92 percent of between the phone system and an offi ce a large class of disruptions that will nev- the time. And in four out of every fi ve worker, HAIL-SS keeps an eye on the er disappear, because they benefi t the cases, the model matched the manager’s sailors operating an Aegis naval weap- interrupter. own estimate of the cost of interruption ons system and mediates the many alerts Vertegaal is optimistic nonetheless. during the meeting. that Aegis produces. In combat simula- “By opening up these new sources of in- That sounds impressive, but some ex- tions, HAIL-SS cut the number of inter- formation about how available someone perts in the fi eld remain skeptical. Users ruptions by 50 to 80 percent, allowing is, people will naturally adapt and use may have a very low tolerance for a sys- sailors to handle critical alerts up to them to apply existing social rules of tem that erroneously suppresses one out twice as quickly. The software lowered etiquette,” he predicts. “So just by virtue of every 10 important calls. “The more the perceived diffi culty and stressfulness of letting people know when you’re busy, ‘attentive’ things become, the more un- of the job by one quarter. The U.S. Navy you’ll get fewer interruptions.” predictable they are,” warns Ben Shnei- now plans to deploy HAIL-SS through- derman of the University of Maryland. out the fl eet. W. Wayt Gibbs is senior writer. “We have a history in this community of creating ‘smart’ devices that people don’t MORE TO EXPLORE use because they can’t understand how Attentive User Interfaces. Special section. Edited by Roel Vertegaal in Communications of the they operate.” ACM, Vol. 46, No. 3, pages 30–72; March 2003. Indeed, Vertegaal refl ects, “artifi cial Learning and Reasoning about Interruption. Eric Horvitz and Johnson Apacible. Proceedings of intelligence couldn’t deliver the personal the Fifth International Conference on Multimodal Interfaces, November 2003. Proceedings of the International Workshop on Progress and Future Directions of Adaptive Driver secretary, because it was too complicat- Assistance Research. Washington, D.C., May 2004. Available online at www.volpe.dot.gov/ ed.” Nevertheless, he adds, “I’m pretty opsad/saveit/

KC ARMSTRONG KC sure we can deliver a receptionist.” A variety of relevant technical articles are available online at http://interruptions.net

62 SCIENTIFIC AMERICAN JANUARY 2005 COPYRIGHT 2004 SCIENTIFIC AMERICAN, INC. The deadliest ﬂ u strain in history has been resurrected. What can the 1918 VIRUS reveal about why it killed millions and where more like it may be lurking?

INFLUENZA VICTIMS lie at U.S. Army Camp Hospital No. 45, Aix-les-Bains, France, in 1918. Flu killed 43,000 American

CREDIT CREDIT servicemen mobilized for World War I, representing nearly 40 percent of U.S. military casualties.

www.sciam.com SCIENTIFIC AMERICAN 63 COPYRIGHT 2004 SCIENTIFIC AMERICAN, INC. n September 7, 1918, at the height of World War I, a soldier at an army training O camp outside Boston came to sick call with a high fever. Doctors diagnosed him with meningitis but changed their minds the next day when a dozen more soldiers were hospitalized with respiratory symptoms. Thirty-six new cases of this unknown illness appeared on the 16th. Incredibly, by September 23rd, 12,604 cases had been reported in the camp of 45,000 soldiers. By the end of the outbreak, one third of the camp’s population would come down with this severe disease, and nearly 800 of them would die. The soldiers who perished often developed a bluish skin color and RED CROSS NURSES in St. Louis carry a fl u patient in 1918. Health workers, police and a panicked struggled horribly before succumbing to public donned face masks for protection as the virus swept the country. Nearly a third of all Americans were infected during the pandemic, and 675,000 of them died. death by suffocation. Many died less than 48 hours after their symptoms ap- study because infl uenza would not be es have emerged twice since 1918—in peared, and at autopsy their lungs were identifi ed as a virus until the 1930s. But 1957 and 1968. And fl u strains that usu- fi lled with fl uid or blood. thanks to incredible foresight by the U.S. ally infect only animals have also peri- Because this unusual suite of symp- Army Medical Museum, the persistence odically caused disease in humans, as toms did not fi t any known malady, a of a pathologist named Johan Hultin, and seen in the recent outbreak of avian in- distinguished pathologist of the era, advances in genetic analysis of old tissue fl uenza in Asia. Our two principal goals William Henry Welch, speculated that samples, we have been able to retrieve are determining what made the 1918 in- “this must be some new kind of infec- parts of the 1918 virus and study their fl uenza so virulent, to guide develop-

tion or plague.” Yet the disease was nei- features. Now, more than 80 years after ment of infl uenza treatments and pre- ) ther plague nor even new. It was just in- the horrible natural disaster of 1918– ventive measures, and establishing the fl uenza. Still, this particularly virulent 1919, tissues recovered from a handful of origin of the pandemic virus, to better this page and infectious strain of the fl u virus is victims are answering fundamental ques- target possible sources of future pan- thought to have killed as many as 40 tions both about the nature of this pandemic strains. million people around the world be- demic strain and about the workings of tween 1918 and 1919. infl uenza viruses in general. Hunting the 1918 Virus This most lethal fl u outbreak in mod- The effort is not motivated merely by in many respects, the 1918 infl u- ern history disappeared almost as quick- historical curiosity. Because infl uenza enza pandemic was similar to others be- ly as it emerged, and its cause was long viruses continually evolve, new infl uen- fore it and since. Whenever a new fl u believed lost to time. No one had pre- za strains continually threaten human strain emerges with features that have ); AMERICAN RED CROSS MUSEUM ( MUSEUM CROSS RED AMERICAN ); served samples of the pathogen for later populations. Pandemic human fl u virus- never been encountered by most people’s immune systems, widespread fl u out- The Mystery of 1918 breaks are likely. But certain unique Overview/ characteristics of the 1918 pandemic preceding pages preceding

■ The ﬂ u pandemic that swept the globe in 1918–1919 was exceptional for the have long remained enigmatic. ) ( sheer numbers it killed, especially the number of young people who For instance, it was exceptional in

succumbed to the unusually virulent fl u virus. both its breadth and depth. Outbreaks hospital ■ What made the strain so deadly was a longstanding medical mystery until the swept across Europe and North Ameri- authors devised techniques that allowed them to retrieve the 1918 virus’s ca, spreading as far as the Alaskan wil- genes from victims’ preserved tissues. derness and the most remote islands of ( CORBIS ); ■ Analysis of those genes and the proteins they encode revealed viral features the Pacifi c. Ultimately, one third of the that could have both suppressed immune defenses and provoked a violent world’s population may have been in- virus flu immune reaction in victims, contributing to the high mortality. fected. The disease was also unusually ■ Known bird and mammal infl uenza hosts are unlikely sources of the pandemic severe, with death rates of 2.5 to 5 per- virus, so its origin remains unsolved. cent—up to 50 times the mortality seen

in other inﬂ uenza outbreaks. RETSECKGEORGE (

64 SCIENTIFIC AMERICAN JANUARY 2005 COPYRIGHT 2004 SCIENTIFIC AMERICAN, INC. By the fall of 1918 everyone in Eu- the 1918 virus preserved in the victims’ damage characteristic of patients who rope was calling the disease the “Span- lungs. Unfortunately, all attempts to cul- died rapidly. Because the infl uenza virus ish” infl uenza, probably because neutral ture live infl uenza virus from these spec- normally clears the lungs just days after Spain did not impose the wartime cen- imens were unsuccessful. infection, we had the greatest chance of sorship of news about the outbreak prev- In 1995 our group initiated an at- fi nding virus remnants in these victims. alent in combatant countries. The name tempt to fi nd the 1918 virus using a dif- The standard practice of the era was stuck, although the fi rst outbreaks, or ferent source of tissue: archival autopsy to preserve autopsy specimens in formal- spring wave, of the pandemic seemingly specimens stored at the Armed Forces In- dehyde and then embed them in paraffi n, arose in and around military camps in stitute of Pathology (AFIP). For several so fi shing out tiny genetic fragments of the U.S. in March 1918. The second, years, we had been developing expertise the virus from these 80-year-old “fi xed” main wave of the global pandemic oc- in extracting fragile viral genetic material tissues pushed the very limits of the tech- curred from September to November from damaged or decayed tissue for di- niques we had developed. After an ago- 1918, and in many places yet another se- agnostic purposes. In 1994, for instance, nizing year of negative results, we found vere wave of infl uenza hit in early 1919. we were able to use our new techniques the first influenza-positive sample in Antibiotics had yet to be discovered, to help an AFIP marine mammal pathol- 1996, a lung specimen from a soldier who and most of the people who died during ogist investigate a mass dolphin die-off died in September 1918 at Fort Jackson, the pandemic succumbed to pneumonia that had been blamed on red tide. Al- S.C. We were able to determine the se- caused by opportunistic bacteria that in- though the available dolphin tissue sam- quence of nucleotides in small fragments fected those already weakened by the ples were badly decayed, we extracted of fi ve infl uenza genes from this sample. fl u. But a subset of infl uenza victims died enough pieces of RNA from them to iden- But to confi rm that the sequences be- just days after the onset of their symp- tify a new virus, similar to the one that longed to the lethal 1918 virus, we kept After an AGONIZING YEAR of negative results, we found THE FIRST CASE in 1996. toms from a more severe viral pneumo- causes canine distemper, which proved looking for more positive cases and iden- nia— caused by the fl u itself—that left to be the real cause of the dolphin deaths. tifi ed another one in 1997. This soldier their lungs either massively hemorrhaged Soon we began to wonder if there were also died in September 1918, at Camp or fi lled with fl uid. Furthermore, most any older medical mysteries we might Upton, N.Y. Having a second sample al- deaths occurred among young adults be- solve with our institute’s resources. lowed us to confi rm the gene sequences tween 15 and 35 years old, a group that A descendant of the U.S. Army Med- we had, but the tiny quantity of tissue rarely dies from infl uenza. Strikingly, ical Museum founded in 1862, the AFIP remaining from these autopsies made us people younger than 65 years accounted has grown along with the medical spe- worry that we would never be able to for more than 99 percent of all “excess” cialty of pathology and now has a collec- generate a complete virus sequence. infl uenza deaths (those above normal tion of three million specimens. When we A solution to our problem came from annual averages) in 1918–1919. realized that these included autopsy sam- an unexpected source in 1997: Johan Efforts to understand the cause of ples from 1918 fl u victims, we decided to Hultin, by then a 73-year-old retired pa- the 1918 pandemic and its unusual fea- go after the pandemic virus. Our initial thologist, had read about our initial re- tures began almost as soon as it was study examined 78 tissue samples from sults. He offered to return to Brevig Mis- over, but the culprit virus itself remained victims of the deadly fall wave of 1918, sion to try another exhumation of 1918 hidden for nearly eight decades. In 1951 focusing on those with the severe lung fl u victims interred in permafrost. Forty- scientists from the University of Iowa, including a graduate student recently ar- JEFFERY K. TAUBENBERGER, ANN H. REID and THOMAS G. FANNING work together at the rived from Sweden named Johan Hultin, Armed Forces Institute of Pathology in Rockville, Md. In 1993 Taubenberger, a molecular went as far as the Seward Peninsula of pathologist, helped to create a laboratory there devoted to molecular diagnostics—iden- Alaska seeking the 1918 strain [see box tifying diseases by their genetic signatures rather than by the microscopic appearance on page 71]. In November 1918 flu of patients’ tissue samples. Early work by Reid, a molecular biologist, led the group to spread through an Inuit fi shing village devise the techniques for extracting DNA and RNA from damaged or decayed tissue that THE AUTHORS now called Brevig Mission in fi ve days, allowed them to retrieve bits and pieces of 1918 fl u virus genes from archived autopsy killing 72 people—about 85 percent of specimens. Fanning, a geneticist with expertise in the evolution of genomes, helped to the adult population. Their bodies had analyze the genes’ relationships to other animal and human fl u viruses. The authors wish since been buried in permafrost, and the to note that the opinions expressed in this article are their own and do not represent the 1951 expedition members hoped to fi nd views of the Department of Defense or the AFIP.

Infl uenza is a small and simple virus—just a hollow lipid ball viruses loose from an infected cell, infl uencing how effi ciently the studded with a few proteins and bearing only eight gene segments virus can spread. Slight changes in these and other fl u proteins can (below). But that is all it needs to induce the cells of living hosts to help the virus infect new kinds of hosts and evade immune make more viruses (bottom). One especially important protein on attack. The alterations can arise through mistakes that occur infl uenza’s surface, hemagglutinin (HA), allows the virus to enter while viral genes are being copied. Or they can be acquired in cells. Its shape determines which hosts a fl u virus strain can trade when the genes of two different fl u viruses infecting the infect. Another protein, neuraminidase (NA), cuts newly formed same cell intermingle (right).

Reassorted INFLUENZA VIRUS viruses The two major surface proteins, HA and NA, protrude from a lipid bilayer. Inside Lipid bilayer (cutaway), eight HA separate RNA segments specify additional proteins that determine NA all aspects of the virus’s function.

Sialic f acid g INFECTION AND REPLICATION A fl u virus’s HA protein binds to sialic acid on the surface of a host organism’s cell (a), allowing the virus to slip inside (b), where it releases its c RNA (c), which enters the cell’s nucleus (d). e Viral RNA There the viral RNA is copied and its genetic instructions are “read,” prompting cellular machinery to produce new viral proteins (e). The new viral RNA and proteins then assemble into viruses that bud from the cell membrane (f). At d fi rst, their surfaces are coated with sialic acid. To prevent viruses from binding to one another’s hemagglutinin proteins and to the host cell surface, neuraminidase clips the sialic acid (g), freeing the viruses to infect other cells. Nucleus Viral RNA copies six years after his fi rst attempt, with per- of these cases and have found that they 100 years belonged to the type A group mission from the Brevig Mission Coun- were nearly identical to the North Amer- of fl u viruses. Flu comes in three main cil, he obtained frozen lung biopsies of ican samples, confirming the rapid forms, designated A, B and C. The latter four fl u victims. In one of these samples, worldwide spread of a uniform virus. two infect only humans and have never from a woman of unknown age, we But what can the sequences tell us about caused pandemics. Type A infl uenza vi- found infl uenza RNA that provided the the virulence and origin of the 1918 ruses, on the other hand, have been key to sequencing the entire genome of strain? Answering those questions re- found to infect a wide variety of ani- the 1918 virus. quires a bit of background about how mals, including poultry, swine, horses, More recently, our group, in collabo- infl uenza viruses function and cause dis- humans and other mammals. Aquatic ration with British colleagues, has also ease in different hosts. birds, such as ducks, serve as the natural been surveying autopsy tissue samples “reservoir” for all the known subtypes from 1918 infl uenza victims from the Flu’s Changing Face of infl uenza A, meaning that the virus Royal London Hospital. We have been each of the three novel infl uenza infects the bird’s gut without causing

able to analyze ﬂ u virus genes from two strains that caused pandemics in the past symptoms. But these wild avian strains RETSECKGEORGE

66 SCIENTIFIC AMERICAN JANUARY 2005 COPYRIGHT 2004 SCIENTIFIC AMERICAN, INC. lular machinery, inducing it to manufac- reassortment with the extensive pool of ture new viral proteins and additional infl uenza viruses infecting wild birds. copies of viral RNA. These pieces then Normally, infl uenza HAs that are adapt- assemble themselves into new viruses ed to avian hosts bind poorly to the cell- that escape the host cell, proceeding to surface receptors prevalent in the human infect other cells. No proofreading respiratory tract, so an avian virus’s HA mechanism ensures that the RNA copies binding affi nity must be somewhat mod- Nucleus are accurate, so mistakes leading to new ifi ed before the virus can replicate and mutations are common. What is more, spread effi ciently in humans. Until re- should two different influenza virus cently, existing evidence suggested that strains infect the same cell, their RNA a wholly avian infl uenza virus probably segments can mix freely there, produc- could not directly infect humans, but 18 ing progeny viruses that contain a com- people were infected with an avian bination of genes from both the original H5N1 infl uenza virus in Hong Kong in viruses. This “reassortment” of viral 1997, and six died. genes is an important mechanism for Outbreaks of an even more patho- generating diverse new strains. genic version of that H5N1 strain be- Different circulating infl uenza A vi- came widespread in Asian poultry in Host cell ruses are identifi ed by referring to two 2003 and 2004, and more than 30 peo- signature proteins on their surfaces. One ple infected with this virus have died in is hemagglutinin (HA), which has at Vietnam and Thailand. least 15 known variants, or subtypes. The virulence of an infl uenza virus Strain 1 Another is neuraminidase (NA), which once it infects a host is determined by a has nine subtypes. Exposure to these complex set of factors, including how proteins produces distinctive antibodies readily the virus enters different tissues, Strain 2 in a host, thus the 1918 strain was the how quickly it replicates, and the vio- fi rst to be named, “H1N1,” based on an- lence of the host’s immune response to tibodies found in the bloodstream of the intruder. Thus, understanding ex- pandemic survivors. Indeed, less viru- actly what made the 1918 pandemic in- lent descendants of H1N1 were the pre- fl uenza strain so infectious and so viru- dominant circulating fl u strains until lent could yield great insight into what REASSORTMENT 1957, when an H2N2 virus emerged, makes any infl uenza strain more or less New fl u strains can result when causing a pandemic. Since 1968, the of a threat. two different viruses infect the H3N2 subtype, which provoked the same cell (above). Copies of their RNA can mix and produce pandemic that year, has predominated. A Killer’s Face progeny with combinations of The HA and NA protein subtypes with the 1918 rna we have re- genes from both parent viruses. present on a given infl uenza A virus are trieved, we have used the virus’s own In this manner, a bird or animal fl u strain can gain genes more than just identifi ers; they are es- genes as recipes for manufacturing its conferring the ability to spread sential for viral reproduction and are component parts—essentially re-creat- more easily among humans. primary targets of an infected host’s im- ing pieces of the killer virus itself. The mune system. The HA molecule initiates fi rst of these we were eager to examine can mutate over time or exchange genet- infection by binding to receptors on the was the hemagglutinin protein, to look ic material with other infl uenza strains, surface of certain host cells. These tend for features that might explain the ex- producing novel viruses that are able to to be respiratory lining cells in mammals ceptional virulence of the 1918 strain. spread among mammals and domestic and intestinal lining cells in birds. The We could see, for example, that the poultry. NA protein enables new virus copies to part of the 1918 HA that binds with a The life cycle and genomic structure escape the host cell so they can go on to host cell is nearly identical to the bind- of infl uenza A virus allow it to evolve and infect other cells. ing site of a wholly avian infl uenza HA exchange genes easily. The virus’s genet- After a host’s fi rst exposure to an [see illustration on page 69]. In two of ic material consists of eight separate HA subtype, antibodies will block re- the 1918 isolates, this receptor-binding RNA segments encased in a lipid mem- ceptor binding in the future and are thus site differs from an avian form by only brane studded with proteins [see top very effective at preventing reinfection one amino acid building block. In the illustration on opposite page]. To repro- with the same strain. Yet fl u viruses with other three isolates, a second amino duce, the virus binds to and then enters HA subtypes that are new to humans pe- acid is also altered. These seemingly a living cell, where it commandeers cel- riodically appear, most likely through subtle mutations may represent the min-

When analyzing the genes of the 1918 virus revealed no spread between humans, either by mutating or by acquiring defi nitive reasons for the pandemic strain’s virulence, our new genes through reassortment with a circulating human fl u group turned to reverse genetics—a method of understanding strain. That dreaded development would increase the the function of genes by studying the proteins they encode. In possibility of a human pandemic. Hoping to predict and collaboration with scientists from the Mount Sinai School of thereby prevent such a disaster, scientists at the CDC and Medicine, the Centers for Disease Control and Prevention, the Erasmus University in the Netherlands are planning to test U.S. Department of Agriculture, the University of Washington and combinations of H5N1 with current human fl u strains to the Scripps Research Institute, we “built” assess the likelihood of their occurring infl uenza viruses containing one or more of naturally and their virulence in people. the 1918 virus’s genes, so we could see What these experiments will reveal, as how these recombinant viruses behaved in in our group’s work with the 1918 virus Gene copies animals and human cell cultures. genes, is crucial to understanding how To construct these viruses, we infl uenza pandemics form and why they employed a new technique called plasmid- cause disease. Some observers have based reverse genetics, which requires questioned the safety of experimenting fi rst making DNA copies of fl u genes that Plasmids with lethal fl u strains, but all of this normally exist in RNA form. Each DNA gene research is conducted in secure copy is then inserted into a tiny ring of laboratories designed specifi cally to deal DNA called a plasmid. Different with highly pathogenic infl uenza viruses. combinations of these plasmids can be What is more, re-creating the 1918 injected into living cells, where cellular virus proteins enabled us to establish that machinery will execute the genetic Cell culture currently available antiviral drugs, such as instructions they bear and manufacture amantadine or the newer neuraminidase fl u viruses with only the desired inhibitors, such as oseltamivir (Tamifl u), combination of genes. would be effective against the 1918 strain Reverse genetics not only allows us to in the case of an accidental infection. The study the 1918 virus, it will allow New fl u H5N1 viruses are also sensitive to the scientists in the U.S. and Europe to virus neuraminidase inhibitors. explore how great a threat the H5N1 avian Scientists in the U.S. and U.K. also fl u virus poses to humans. Since January recently employed plasmid-based reverse PLASMID-BASED reverse genetics 2004, that strain—which is now present genetics to create a seed strain for a lets scientists custom-manufacture in birds in 10 Asian countries—has fl u viruses. DNA copies of genes human vaccine against H5N1. They made a infected more than 40 people, killing more from two different fl u strains (blue version of the H5N1 virus lacking the wild than 30 of them. One of the casualties and red) are inserted into DNA rings strain’s most deadly features, so that was a mother who is believed to have called plasmids. The gene-bearing manufacturers could safely use it to contracted the virus from her daughter, plasmids are then injected into a produce a vaccine [see “The Scientifi c rather than directly from a bird. culture of living cells, which American 50,” December 2004]. Clinical manufacture whole fl u viruses Such human-to-human transmission trials of that H5N1 vaccine were scheduled containing the desired combination could suggest that in their case the avian of genes. to begin at the end of 2004. virus had adapted to be more easily —J.K.T., A.H.R. and T.G.F. imal change necessary to allow an avi- protein must be cleaved into two pieces circulating in Asia. We did not, however, an-type HA to bind to mammalian-type by a gut-specifi c protein-cutting enzyme, fi nd it in the 1918 virus. receptors. or protease, supplied by the host. Some The other mutation with a signifi - But while gaining a new binding af- avian H5 and H7 subtype viruses ac- cant effect on virulence has been seen in fi nity is a critical step that allows a virus quire a gene mutation that adds one or the NA gene of two influenza virus to infect a new type of host, it does not more basic amino acids to the cleavage strains that infect mice. Again, muta- necessarily explain why the 1918 strain site, allowing HA to be activated by ubiq- tions at a single amino acid appear to was so lethal. We turned to the gene se- uitous proteases. In chickens and other allow the virus to replicate in many dif- quences themselves, looking for features birds, infection by such a virus causes ferent body tissues, and these fl u strains that could be directly related to viru- disease in multiple organs and even the are typically lethal in laboratory mice. lence, including two known mutations in central nervous system, with a very high But we did not see this mutation in the other fl u viruses. One involves the HA mortality rate. This mutation has been NA of the 1918 virus either.

gene: to become active in a cell, the HA observed in the H5N1 viruses currently Because analysis of the 1918 virus’s RETSECKGEORGE

68 SCIENTIFIC AMERICAN JANUARY 2005 COPYRIGHT 2004 SCIENTIFIC AMERICAN, INC. genes was not revealing any characteris- a tissue culture of human lung cells, we unclear, this protein may have played a tics that would explain its extreme viru- found that a virus with the 1918 NS1 key role in the 1918 strain’s virulence. lence, we initiated a collaborative effort gene was indeed more effective at block- These ongoing experiments are pro- with several other institutions to re-create ing the host’s type I IFN system. viding a window to the past, helping sci- parts of the 1918 virus itself so we could To date, we have produced recombi- entists understand the unusual charac- observe their effects in living tissues. nant infl uenza viruses containing be- teristics of the 1918 pandemic. Similarly, A new technique called plasmid- tween one and fi ve of the 1918 genes. these techniques will be used to study based reverse genetics allows us to copy Interestingly, we found that any of the what types of changes to the current 1918 viral genes and then combine them recombinant viruses possessing both H5N1 avian infl uenza strain might give with the genes of an existing infl uenza the 1918 HA and NA genes were lethal that extremely lethal virus the potential strain, producing a hybrid virus. Thus, in mice, causing severe lung damage to become pandemic in humans [see box we can take an infl uenza strain adapted similar to that seen in some of the pan- on opposite page]. An equally compel- to mice, for example, and give it differ- demic fatalities. When we analyzed ling question is how such virulent strains ent combinations of 1918 viral genes. these lung tissues, we found signatures emerge in the fi rst place, so our group Then, by infecting a live animal or a hu- of gene activation involved in common has also been analyzing the 1918 virus’s man tissue culture with this engineered infl ammatory responses. But we also genes for clues about where it might have virus, we can see which components of found higher than normal activation of originated. Seemingly subtle mutations may allow an AVIAN hemagglutinin to bind to MAMMALIAN receptors.

the pandemic strain might have been key genes associated with the immune sys- Seeking the Source to its pathogenicity. tem’s offensive soldiers, T cells and mac- the best approach to analyzing For instance, the 1918 virus’s dis- rophages, as well as genes related to tis- the relationships among infl uenza virus- tinctive ability to produce rapid and ex- sue injury, oxidative damage, and apo- es is phylogenetics, whereby hypotheti- tensive damage to both upper and lower ptosis, or cell suicide. cal family trees are constructed using respiratory tissues suggests that it repli- More recently, Yoshihiro Kawaoka viral gene sequences and knowledge of cated to high numbers and spread quick- of the University of Wisconsin–Madison how often genes typically mutate. Be- ly from cell to cell. The viral protein NS1 reported similar experiments with 1918 cause the genome of an infl uenza virus is known to prevent production of type I fl u genes in mice, with similar results. consists of eight discrete RNA segments interferon (IFN)—an “early warning” But when he tested the HA and NA genes that can move independently by reas- system that cells use to initiate an im- separately, he found that only the 1918 sortment, these evolutionary studies mune response against a viral infection. HA produced the intensive immune re- must be performed separately for each When we tested recombinant viruses in sponse, suggesting that for reasons as yet gene segment.

VOL. 303, PAGES 1866–1870; 2004. © 2004 AAAS We have completed analyses of fi ve Human-adapted Avian-adapted 1918 Flu of the 1918 virus’s eight RNA segments, H3 H5 H1 and so far our comparisons of the 1918 SCIENCE, SCIENCE, fl u genes with those of numerous human, swine and avian infl uenza viruses always place the 1918 virus within the human and swine families, outside the avian virus group [see box on next page]. The 1918 viral genes do have some avian Amino features, however, so it is probable that acid change the virus originally emerged from an HEMAGGLUTININ (HA) of the 1918 fl u strain was re-created from its gene sequence by the authors’ avian reservoir sometime before 1918. collaborators so they could examine the part that binds to a host cell’s sialic acid and allows the Clearly by 1918, though, the virus had virus to enter the cell. HA binding sites usually are shaped differently enough to bar cross-species acquired enough adaptations to mam- infection. For instance, the human-adapted H3-type HA has a wide cavity in the middle of its mals to function as a human pandemic binding site (left), whereas the avian H5 cavity (center) is narrow. The 1918 H1-type HA (right) virus. The question is, where? more closely resembles the avian form, with only a few minor differences in the sequence of its amino acid building blocks. One of these alterations (above right) slightly widens the central When we analyzed the 1918 hemag- cavity, apparently just enough to have allowed a fl u virus with this avian-type HA to infect glutinin gene, we found that the se-

REPRINTED WITH PERMISSION FROM FIGURE 4 IN STEVENS ET AL. IN IN AL. ET STEVENS IN 4 FIGURE FROM PERMISSION WITH REPRINTED hundreds of millions of humans in 1918–1919. quence has many more differences from

www.sciam.com SCIENTIFIC AMERICAN 69 COPYRIGHT 2004 SCIENTIFIC AMERICAN, INC. mans and swine during the 1918 pandemic, but we believe that the direction Flu Family Tree of transmission was most probably from Seeking clues to the origin of the 1918 virus’s Yamagata 1989 humans to pigs. There are numerous ex- hemagglutinin (HA), the authors analyzed Massachusetts 1990 amples of human influenza A virus gene sequences for the H1-subtype of HA from Stockholm 1990 strains infecting swine since 1918, but Fiji 1988 a variety of ﬂ u strains and constructed swine inﬂ uenza strains have been iso- U.S.S.R. 1977 a phylogeny showing their evolutionary lated only sporadically from humans.

relationships. Samples of the Fort Monmouth 1947 Human Leningrad 1954 Nevertheless, to explore the possibility 1918 strain (S. Carolina, New York, Brazil 1978 that the 1918 HA may have started as an Brevig) fell within the family Puerto Rico 1934 avian form that gradually adapted to of human-adapted fl u viruses. Cambridge 1939 mammalian hosts in swine, we looked at The 1918 H1 gene’s distance Wilson Smith 1933 from the known avian family Wilson Smith N 1933 a current example of how avian viruses could indicate that it originated S. CAROLINA 1918 evolve in pigs—an avian H1N1 infl uenza in an avian fl u strain but NEW YORK 1918 lineage that has become established in BREVIG 1918 spent time evolving European swine over the past 25 years. Iowa 1930 in an unidentifi ed host Iowa 1937 We found that even 20 years of evolution before emerging IIIinois 1963 in swine has not resulted in the number in 1918. Supporting Nebraska 1992 of changes from avian sequences exhib- Ehime 1980 this conclusion, Swine ited by the 1918 pandemic strain. a contemporary avian St. Hyacinthe 1991 Iowa 1988 When we applied these types of anal- strain found in a New Jersey 1976 yses to four other 1918 virus genes, we preserved Brant goose Hong Kong 1974 came to the same conclusion: the virus (Alaska 1917) was Italy 1981 evolutionarily distant Alberta 1976 that sparked the 1918 pandemic could Wisconsin 1980b well have been an avian strain that was from the 1918 strain Wisconsin 1980a and more similar to Tennessee 1985 evolutionarily isolated from the typical modern bird fl us. Minnesota 1981 wild waterfowl infl uenza gene pool for ALASKA 1917 some time— one that, like the SARS Hong Kong 1976 Hong Kong /8/76 coronavirus, emerged into circulation Germany 1987 Avian among humans from an as yet unknown Australia/749/80 animal host. Germany 1991 Germany 1990 Bavaria 1977 Future Investigations Hong Kong 1976 our analyses of fi ve RNA segments Hong Kong 1977 from the 1918 virus have shed some light on its origin and strongly suggest that avian sequences than do the 1957 H2 collected in 1917 and stored in ethanol the pandemic virus was the common an- and 1968 H3 subtypes. Thus, we con- in the Smithsonian’s bird collections. As cestor of both subsequent human and cluded, either the 1918 HA gene spent it turned out, the 1917 avian H1 sequence swine H1N1 lineages, rather than hav- some length of time in an intermediate was closely related to modern avian ing emerged from swine. To date, ana- host where it accumulated many chang- North American H1 strains, suggesting lyzing the viral genes has offered no de- es from the original avian sequence, or that avian H1 sequences have changed fi nitive clue to the exceptional virulence the gene came directly from an avian vi- little over the past 80 years. Extensive se- of the 1918 virus strain. But experiments rus, but one that was markedly different quencing of additional wild bird H1 with engineered viruses containing 1918 from known avian H1 sequences. strains may yet identify a strain more genes indicate that certain of the 1918 To investigate the latter possibility similar to the 1918 HA, but it may be that viral proteins could promote rapid virus that avian H1 genes might have changed no avian H1 will be found resembling the replication and provoke an intensely de- substantially in the eight decades since 1918 strain because, in fact, the HA did structive host immune response. the 1918 pandemic, we collaborated not reassort directly from a bird strain. In future work, we hope that the with scientists from the Smithsonian In that case, it must have had some 1918 pandemic virus strain can be Institution’s Museum of Natural Histo- intermediate host. Pigs are a widely sug- placed in the context of infl uenza virus- ry and Ohio State University. After ex- gested possibility because they are es that immediately preceded and fol- amining many preserved birds from the known to be susceptible to both human lowed it. The direct precursor of the era, our group isolated an avian subtype and avian viruses. Indeed, simultaneous pandemic virus, the fi rst or spring wave

H1 inﬂ uenza strain from a Brant goose outbreaks of inﬂ uenza were seen in hu- virus strain, lacked the autumn wave’s JOHNSON JOHNNY

70 SCIENTIFIC AMERICAN JANUARY 2005 COPYRIGHT 2004 SCIENTIFIC AMERICAN, INC. exceptional virulence and seemed to spread less easily. At present, we are Persistence Pays Off seeking infl uenza RNA samples from victims of the spring wave to identify Visiting Alaska in the summer of 1949, Swedish medical student Johan Hultin met any genetic differences between the two Lutheran missionaries in Fairbanks who told him of the 1918 fl u pandemic’s toll on strains that might help elucidate why the Inuit villages. One, a tiny settlement on the Seward Peninsula called Teller Mission, was all but wiped out autumn wave was more severe. Similar- in November 1918. Overwhelmed missionaries had to ly, fi nding pre-1918 human infl uenza call in the U.S. Army to help bury 72 victims’ bodies in RNA samples would clarify which gene a mass grave, which they marked by two crosses. segments in the 1918 virus were com- Haunted by the story, Hultin (right, center and pletely novel to humans. The unusual below) headed to the University of Iowa to begin his mortality among young people during doctoral studies in microbiology. There he kept thinking the 1918 pandemic might be explained about the 1918 pandemic and wondering if the deadly if the virus shared features with earlier virus that caused it could be retrieved for study from HULTIN in Brevig circulating strains to which older people bodies that may have been preserved by the Alaskan grave, 1951 had some immunity. And fi nding sam- permafrost. In the summer of 1951, Hultin convinced ples of H1N1 from the 1920s and later two Iowa faculty, a virologist and a pathologist, to visit the village, then called Brevig would help us understand the 1918 vi- Mission. With permission from tribal elders, the scientists excavated the grave and rus’s subsequent evolution into less viru- obtained tissue specimens from what remained of several victims’ lungs. lent forms. Back in Iowa, the team tried and tried to grow live virus from the specimens but We must remember that the mecha- never could. In retrospect, that was perhaps just as well since biological containment nisms by which pandemic fl u strains equipment for dangerous pathogens did not exist at the time. originate are not yet fully understood. Hultin’s disappointment led him to abandon his Ph.D. and become a pathologist Because the 1957 and 1968 pandemic instead. Retired and living in San Francisco in 1997, Hultin read our group’s fi rst strains had avian-like HA proteins, it published description of the 1918 genes we retrieved from autopsy specimens, seems most likely that they originated in and it rekindled his hope of fi nding the entire 1918 virus. He wrote to me, eager to the direct reassortment of avian and hu- try to procure new lung specimens from Brevig Mission for us to work with. He man virus strains. The actual circum- offered to leave immediately for Alaska, and I agreed. stances of those reassortment events At the same time, Hultin tracked down his 1951 expedition mates to ask if they had kept any of the original Brevig specimens. We reasoned that those tissue have never been identifi ed, however, so samples obtained just 33 years after the pandemic and then preserved might be in no one knows how long it took for the better condition than specimens taken later. As it turned out, one of Hultin’s novel strains to develop into human colleagues had kept the material in storage for years but fi nally deemed it useless pandemics. and threw it out. He had disposed of the last specimens just the year before, in 1996. The 1918 pandemic strain is even Fortunately, Hultin once again got permission from the Brevig Mission Council more puzzling, because its gene se- to excavate the 1918 grave in August 1997. And quences are consistent neither with di- this time he found the body of a young woman HULTIN in rect reassortment from a known avian Brevig grave, who had been obese in life. Hultin said later 1997 strain nor with adaptation of an avian that he knew instantly her tissue samples strain in swine. If the 1918 virus should would contain the 1918 virus—together with prove to have acquired novel genes the cold temperature, her thick layer of fat had through a different mechanism than almost perfectly preserved her lungs. He was

) subsequent pandemic strains, this could right, and her tissue provided us with the entire have important public health implica- genome of the 1918 pandemic virus. —J.K.T. bottom tions. An alternative origin might even have contributed to the 1918 strain’s exceptional virulence. Sequencing of many MORE TO EXPLORE more avian inﬂ uenza viruses and re- Devil’s Flu: The World’s Deadliest Influenza Epidemic and the Scientific Hunt for the Virus That Caused It. Pete Davies. Henry Holt and Co., 2000.

), JOHAN HULTIN ( HULTIN JOHAN ), search into alternative intermediate America’s Forgotten Pandemic: The Influenza of 1918. Second edition. Alfred W. Crosby. top hosts other than swine, such as poultry, Cambridge University Press, 2003. wild birds or horses, may provide more The Origin of the 1918 Pandemic Influenza Virus: A Continuing Enigma. Ann H. Reid and Jeffery K. clues to the 1918 pandemic’s source. Taubenberger in Journal of General Virology, Vol. 84, Part 9, pages 2285–2292; September 2003. Until the origins of such strains are bet- Global Host Immune Response: Pathogenesis and Transcriptional Profiling of Type A ter understood, detection and preven- Influenza Viruses Expressing the Hemagglutinin and Neuraminidase Genes from the 1918 Pandemic Virus. J. C. Kash, C. F. Basler, A. Garcia-Sastre, V. Carter, R. Billharz, D. E. Swayne, tion efforts may overlook the beginning R. M. Przygodzki, J. K. Taubenberger, M. G. Katze and T. M. Tumpey in Journal of Virology, Vol. 78,

ASSOCIATED PRODUCERS ( of the next pandemic. No. 17, pages 9499–9511; September 2004.

www.sciam.com SCIENTIFIC AMERICAN 71 COPYRIGHT 2004 SCIENTIFIC AMERICAN, INC. Beholder Wonders under the lens of the Eye Text by Emily Harrison of the of optical microscope COPYRIGHT 2004 SCIENTIFIC AMERICAN, INC.

A SEA OF SWIMMING OF SWIMMING A SEA (45 beetle the of thorax and eye the of this image captured Wash., Issaquah, of Krebs B. Charles Argema mittrei of detail this for illumination brightfi eld and fi ber-optic used Scotland, Aberdeen, of the of University Mackenzie Kevin beetle. metallic and aMadagascar moon moth these close-ups of a pavement on oil of aslick and × ) using refl) using light. ected Chrysochroa fulminans Chrysochroa — or so could seem ’s wing (100 wing ’s goldfi sh × ).

CREDIT CREDIT www.sciam.com it. toknow opportunity have the ordinarily, not, eye does the as of life of photomicrography. aslice oneoffers masters Each by modern some closer, captured as of looking art the world. macroscopic the in we notice anything as small as times 1,000 of light, awavelength as world resolve of slivers the small as They space. inner it todeep taking inward, vision our turn microscopes away of eye’s light-years the optical from everyday billions demesne, tances todis- space, into deep view our extend telescopes optical While access. can eyes unaided our distances of scientifi art the lens, and light as tal fundamen- as may be that materials With of techniques. chest tool amarvelous holds science more, seeing There is infi The pairs of images here, selected from entries to Nikon’s annual Small World Competition, epitomize epitomize World to Nikon’s Small Competition, entries from annual selected here, of images pairs The nite beauty in the world, world, the in beauty nite COPYRIGHT 2004 SCIENTIFIC AMERICAN, INC. c observation expands the visible world far beyond the depths and and world depths beyond visible the the far expands c observation if only we fi we only if nd the means to see it. And when it comes to it comes when And it. tosee means nd the SCIENTIFIC AMERICAN SCIENTIFIC Continued on page 77 page on Continued

ALL MICROSCOPE IMAGES COURTESY OF NIKON INSTRUMENTS; MARK LASKO (moon moth); CLIVE PRATT (beetle) CREDIT CREDIT

PAOLO MAZZEI (silkworm, opposite page) trachea of a silkworm (70 asilkworm of trachea called darkfi eld illumination, darkficalled illumination, eld Adelaide snapped this view snapped thisAdelaide view Greg W. Rouse of the South South the of W. Rouse Greg ( abounds, even among the the among even abounds, worms. Using a technique atechnique Using worms. EXTRAVAGANT GEOMETRY England, illuminated the the illuminated England, above pachycera Walker of HuddersfiWalker of eld, polychaete Australian Museum in ) of the polygonous polygonous the ) of (45 Myrianida Myrianida × ). Ian C. COPYRIGHT 2004 SCIENTIFIC AMERICAN, INC. × ). SCIENTIFIC AMERICAN

75 76

CREDIT CREDIT Márkus of the Hungarian Academy the Academy of Hungarian Márkus lights ( lights beginning stages of the botanical the botanical of stages beginning fortune cookie–shaped pollen on cookie–shaped fortune Michigan State University found found University State Michigan Taraxacum spindly tree strung with holiday with strung spindly tree (1,450 these intimate views show the the show views intimate these confocal laser technique. The The technique. laser confocal life cycle. Shirley A. Owens of of Owens A. Shirley cycle. life with flwith by Róbert uorescence the anther of the spiderwort thethe of spiderwort anther PUNCTUATED BY POLLEN, Trandescantia virginiana stigma of the dandelion dandelion the of stigma of Sciences in Szeged. above right × ), photographed with a with photographed ), (160 × ) the is actually ), as captured COPYRIGHT 2004 SCIENTIFIC AMERICAN, INC. Emily Harrison is photography editor of of light symphony atiny yield each successful, when images, resulting the And contours. its tohighlight angles multiple markers, imbue it with a rainbow of illuminations, or shadow it from fl different with proteins various its tag sugars, its may stain study, under amicroscopist asample in patterns Tocroscope. visualize of ami- eyepiece at the view into transparent very often the and tiny very of music piece adynamic tocreate aurally manipulates poser 73 page from Continued Magnifi cation, resolution and contrast SCIENTIFIC AMERICAN SCIENTIFIC Scientifi — the same properties acom- properties same the — and insight. c American. c American.

— uorescent uorescent bring the the bring

THOMAS G. BARNES (spiderwort); CHARLIE KANE (dandelion) CREDIT CREDIT

By Gary Stix

t the IBM Thomas J. Watson Research Laboratory, Charles Bennett is known as a brilliant theoretician—one of the fathers of the emerging fi eld of quantum computing. Like many theorists, he has not logged much experience in the laboratory. His absentmindedness in relation to the physical world once transformed the color of a teapot from green to red when he left it on a double boiler too long. But in 1989 Bennett and colleagues John A. Smolin A and Gilles Brassard cast caution aside and undertook a groundbreaking experiment that would demonstrate a new cryptography based on the principles of quantum mechanics. The team put together an experiment in which photons moved down a 30-centime- ter channel in a light-tight box called “Aunt Martha’s coffi n.” The direction in which the photons oscillated, their polarization, represented the 0s or 1s of a series of quantum bits, or qubits. The qubits constituted a cryptographic “key” that could be used to encrypt or decipher a message. What kept the key from prying eavesdroppers was Heisen- berg’s uncertainty principle—a foundation of quantum physics that dictates that the measurement of one property in a quantum state will perturb another. In a quantum cryptographic system, any interloper tapping into the stream of photons will alter them in a way that is detectable to the sender and the receiver. In principle, the technique provides the makings of an unbreakable cryptographic key. Today quantum cryptography has come a long way from the jury-rigged project assembled on a table in Bennett’s offi ce. The National Security Agency or one of the Federal Reserve banks can now buy a quantum-cryptographic system from two small companies—and more products are on the way. This new method of encryption represents the fi rst major commercial implementation for what has become known as quantum information science, which blends quantum mechanics and information theory. The ultimate technology to emerge from the fi eld may be a quantum computer so powerful that the only way to protect against its prodigious code-breaking capability may be to deploy quantum-cryptographic techniques. The challenge modern cryptographers face is for sender and receiver to share a key

JEAN-FRANCOIS PODEVIN PODEVIN JEAN-FRANCOIS while ensuring that no one has ﬁ lched a copy. A method called public-key cryptography

Alice and Bob try to keep a quantum-cryptographic key secret by transmitting it in the form of polarized photons, a scheme invented by Charles Bennett of IBM and Gilles Brassard of the Photons University of Montreal during the 1980s and now implemented Rectilinear in a number of commercial products. polarization mode To begin creating a key, Alice sends a photon 1through either the 0 or 1 slot of the Diagonal rectilinear or diagonal polarizing ﬁ lters, while polarization making a record of the various orientations. mode

For each incoming bit, Bob chooses Established bit value 0 1 2randomly which ﬁ lter slot he uses for detection and writes down both the polarization and the bit value.

If Eve the eavesdropper tries to spy on 3 Eve 3the train of photons, quantum mechanics Detection prohibits her from using both fi lters to detect fi l t e r the orientation of a photon. If she chooses the wrong fi lter, she may create errors by modifying their polarization. 2 Bob BY SIMON SINGH (1999) SINGH SIMON BY

1 Polarization ﬁ lter Alice Transmitted photon

Unpolarized photon Detection ﬁ l t e r

Laser Alice’s bit sequence: 0 01010111 Alice’s ﬁ lter scheme: Bob’s detection scheme: Bob’s bit measurements: 1 0 1 0 1 0 0 1 1 Retained bit sequence (key): — 0 — 0 1 — — 1 1

After all the photons have reached Bob, 4he tells Alice over a public channel, perhaps by telephone or an e-mail, the sequence of ﬁ lters he used for the incoming Alice 4 Bob

photons, but not the bit value of the photons. THE CODE BOOK: THE SCIENCE OF SECRECY FROM ANCIENT EGYPT TO QUANTUM CRYPTOGRAPHY,

Alice tells Bob during the same 5conversation which ﬁ lters he chose correctly. Those instances constitute the bits that Alice and Bob will use to form the key that they will use to encrypt messages. 5 TOMMY MOORMAN; ADAPTED FROM FROM ADAPTED MOORMAN; TOMMY

80 SCIENTIFIC AMERICAN JANUARY 2005 COPYRIGHT 2004 SCIENTIFIC AMERICAN, INC. is often used to distribute the secret keys for encryption and decoding of a full- WHO SELLS “UNBREAKABLE” KEYS length message. The security of public- COMPANY TECHNOLOGY key cryptography depends on factoriza- id Quantique An optical-fiber-based system sends quantum- tion or other difficult mathematical Geneva, Switzerland cryptographic keys over tens of kilometers problems. It is easy to compute the product of two large numbers but extremely MagiQ Technologies An optical-fiber system sends quantum-cryptographic hard to factor it back into the primes. New York City keys up to 100 kilometers; also includes hardware and The popular RSA cipher algorithm, software for integration into existing networks widely deployed in public-key cryptogra- NEC Scheduled to release an optical-fiber product at the phy, relies on factorization. The secret Tokyo earliest next year after a 2004 demonstration that key being transferred between sender transferred keys over a record 150 kilometers and receiver is encrypted with a publicly QinetiQ Provides systems on a contract basis that transfer keys available key, say, a large number such as Farnborough, England through the air at distances up to 10 kilometers; has 408,508,091 (in practice, the number supplied a system to BBN Technologies in Cambridge, Mass. would be much larger). It can be decrypt- ed only with a private key owned by the The sender, whom cryptographers by Heisenberg. If she makes the measure- recipient of the data, made up of two fac- convention call Alice, sends a string of ments in the wrong mode, even if she re- tors, in this case 18,313 and 22,307. bits, choosing randomly to send photons sends the bits to Bob in the same way she The diffi culty of overcoming a pub- in either the rectilinear or the diagonal measured them, she will inevitably intro- lic-key cipher may hold secret keys se- modes. The receiver, known as Bob in duce errors. Alice and Bob can detect the cure for a decade or more. But the advent crypto-speak, makes a similarly random presence of the eavesdropper by compar- of the quantum information era—and, decision about which mode to measure ing selected bits and checking for errors. in particular, the capability of quantum the incoming bits. The Heisenberg un- Beginning in 2003, two companies— computers to rapidly perform mon- certainty principle dictates that he can id Quantique in Geneva and MagiQ strously challenging factorizations— measure the bits in only one mode, not Technologies in New York City—intro- may portend the eventual demise of RSA both. Only the bits that Bob measured in duced commercial products that send a and other cryptographic schemes. “If the same mode as sent by Alice are guar- quantum-cryptographic key beyond the The arrival of the quantum computer may portend the EVENTUAL DEMISE OF CIPHERS based on factorization. quantum computers become a reality, anteed to be in the correct orientation, 30 centimeters traversed in Bennett’s ex- the whole game changes,” says John thus retaining the proper value [see box periment. And, after demonstrating a Rarity, a professor in the department of on opposite page]. record transmission distance of 150 kilo- electrical and electronics engineering at After transmission, Bob then com- meters, NEC is to come to market with a the University of Bristol in England. municates with Alice, an exchange that product at the earliest next year. Others, Unlike public-key cryptography, need not remain secret, to tell her which such as IBM, Fujitsu and Toshiba, have quantum cryptography should remain of the two modes he used to receive each active research efforts [see table above]. secure when quantum computers arrive photon. He does not, however, reveal the The products on the market can send on the scene. One way of sending a quan- 0- or 1-bit value represented by each pho- keys over individual optical-fi ber links tum-cryptographic key between sender ton. Alice then tells Bob which of the for multiple tens of kilometers. A system and receiver requires that a laser trans- modes were measured correctly. They from MagiQ costs $70,000 to $100,000. mit single photons that are polarized in both ignore photons that were not ob- “A small number of customers are using one of two modes. In the fi rst, photons served in the right mode. The modes and testing the system, but it’s not wide- are positioned vertically or horizontally measured correctly constitute the key ly deployed in any network,” comments (rectilinear mode); in the second, they that serves as an input for an algorithm Robert Gelfond, a former Wall Street are oriented 45 degrees to the left or used to encrypt or decipher a message. quantitative trader who in 1999 found- right of vertical (diagonal mode). In ei- If someone tries to intercept this ed MagiQ Technologies. ther mode, the opposing positions of the stream of photons— call her Eve—she Some government agencies and fi - photons represent either a digital 0 or a 1. cannot measure both modes, thanks to nancial institutions are afraid that an www.sciam.com SCIENTIFIC AMERICAN 81 COPYRIGHT 2004 SCIENTIFIC AMERICAN, INC. company that played a critical role in establishing the Internet. The encryption keys are sent over dedicated links, and the messages ciphered with those keys are transmitted over the Internet. “This is the fi rst continuously running opera- tional quantum-cryptography network outside a laboratory,” notes Chip Elliott of BBN, who heads the project. The network, designed to merely show that the technology works, transfers ordinary unclassifi ed Internet traffi c. “The only secrets I can possibly think of here are where the parking spaces are,” Elliott says. Last fall, id Quantique and a part- ner, the Geneva-based Internet services provider Deckpoint, put on display a network that allowed a cluster of servers in Geneva to have its data backed up at a site 10 kilometers away, with new keys being distributed frequently through a quantum-encrypted link. The current uses for quantum cryptography are in networks of limited geo- graphic reach. The strength of the technique—that anyone who spies on a key transmittal will change it unalterably— also means that the signals that carry quantum keys cannot be amplifi ed by network equipment that restores a weakening signal and allows it to be re- layed along to the next repeater. An optical amplifi er would corrupt qubits. To extend the distance of these links, researchers are looking beyond optical fi bers as the medium to distribute quantum keys. Scientists have trekked to mountaintops—where the altitude mini- mizes atmospheric turbulence—to prove the feasibility of sending quantum keys ENCRYPTION involving quantum states utilizes Midnight, who took over HBO for more through the air. One experiment in 2002 such advanced technologies that much of the than four minutes in 1986.) Among the at Los Alamos National Laboratory cre- work still resides in laboratories such as this one at MagiQ Technologies. prospective customers for quantum- ated a 10-kilometer link. Another, per- cryptographic systems are telecommu- formed that same year by QinetiQ, based encrypted message could be captured nications providers that foresee offering in Farnborough, England, and Ludwig today and stored for a decade or more— customers an ultrasecure service. Maximilian University in Munich, at which time a quantum computer The first attempts to incorporate stretched 23 kilometers between two might decipher it. Richard J. Hughes, a quantum cryptography into actual net- mountaintops in the southern Alps. By researcher in quantum cryptography at works—rather than just point-to-point optimizing this technology—using big- Los Alamos National Laboratory, cites connections—have begun. The Defense ger telescopes for detection, better fi lters other examples of information that Advanced Research Projects Agency has and antirefl ective coatings—it might be must remain confidential for a long funded a project to connect six network possible to build a system that could time: raw census data, the formula for nodes that stretch among Harvard Uni- transmit and receive signals over more Coca-Cola or the commands for a com- versity, Boston University and BBN than 1,000 kilometers, suffi cient to reach

mercial satellite. (Remember Captain Technologies in Cambridge, Mass., a satellites in low earth orbit. A network of SAM OGDEN

82 SCIENTIFIC AMERICAN JANUARY 2005 COPYRIGHT 2004 SCIENTIFIC AMERICAN, INC. satellites would allow for worldwide cov- are sent along to a subsequent link. “This to help decode a message. A software al- erage. The European Space Agency is in is still very much in its infancy. It’s still in gorithm, known as privacy amplifi ca- the early stages of putting together a plan the hands of physics laboratories,” notes tion, helps to guard against this possibil- for an earth-to-satellite experiment. (The Nicolas Gisin, a professor at the Univer- ity by masking the values of the qubits. European Union also launched an effort sity of Geneva, who helped to found id But cryptographers would like to in April to develop quantum encryption Quantique and who has also done exper- have better photon sources and detec- over communications networks, an ef- iments on long-distance entanglement. tors. The National Institute of Standards fort spurred in part by a desire to prevent A quantum memory might be best and Technology (NIST) is one of many eavesdropping by Echelon, a system that implemented with atoms, not photons. groups laboring on these devices. “One intercepts electronic messages for the in- An experiment published in the October very interesting area is the development telligence services of the U.S., Britain and 22 issue of Science showed how this of detectors that can tell the difference other nations.) might work. Building on ideas of re- between one, two or more photons ar- Ultimately cryptographers want searchers from the University of Inns- riving at the same time,” says Alan some form of quantum repeater—in es- bruck in Austria, a group at the Georgia Migdall of NIST. Researchers there have sence, an elementary form of quantum Institute of Technology detailed in the also tried to address the problem of slow computer that would overcome distance paper how two clouds of ultracold ru- transmission speed by generating quan- limitations. A repeater would work bidium atoms could be entangled and, tum keys at a rate of one megabit per through what Albert Einstein famously because of the quantum linkage, could second—100 times faster than any previ- called “spukhafte Fernwirkungen,” be inscribed with a qubit, the clouds ous efforts and enough to distribute keys spooky action at a distance. Anton Zeil- storing the qubit for much longer than a for video applications. inger and his colleagues at the Institute photon can. The experiment then trans- Quantum cryptography may still of Experimental Physics in Vienna, Aus- ferred the quantum state of the atoms, prove vulnerable to some unorthodox tria, took an early step toward a repeater their qubit, onto a photon, constituting attacks. An eavesdropper might sabo- when they reported in the August 19, information transfer from matter to tage a receiver’s detector, causing qubits 2004, issue of Nature that their group light and showing how a quantum mem- received from a sender to leak back into had strung an optical-fi ber cable in a ory might output a bit. By entangling a fi ber and be intercepted. And an inside sewer tunnel under the Danube River clouds, Alex Kuzmich and Dzmitry job will always prove unstoppable. Entanglement SPOOKED EINSTEIN, but researchers have used the phenomenon to “TELEPORT” quantum information.

and stationed an “entangled” photon at Matsukevich of Georgia Tech hope to “Treachery is the primary way,” ob- each end. The measurement of the state create repeaters that can transfer qubits serves Seth Lloyd, an expert in quantum of polarization in one photon (horizon- over long distances. computation at the Massachusetts Insti- tal, vertical, and so on) establishes im- The supposed inviolability of quan- tute of Technology. “There’s nothing mediately an identical polarization that tum cryptography rests on a set of as- quantum mechanics can do about that.” can be measured in the other. sumptions that do not necessarily carry Still, in the emerging quantum informa- Entanglement spooked Einstein, but over into the real world. One of those tion age, these new ways of keeping se- Zeilinger and his team took advantage of assumptions is that only a single photon crets may be better than any others in a link between two entangled photons to represents each qubit. Quantum cryp- the codebooks. “teleport” the information carried by a tography works by taking a pulsed laser third photon a distance of 600 meters and diminishing its intensity to such an MORE TO EXPLORE across the Danube. Such a system might extent that typically it becomes unlikely Quantum Cryptography. Charles H. Bennett, be extended in multiple relays, so that the that any more than one in 10 pulses con- Gilles Brassard and Artur K. Ekert in Scientiﬁ c American, Vol. 267, No. 4, qubits in a key could be transmitted tains a photon—the rest are dark—one pages 50–57; October 1992. across continents or oceans. To make this reason that the data transfer rate is so The Code Book. Simon Singh. a reality will require development of eso- low. But this is only a statistical likeli- Anchor Books, 1999. teric components, such as a quantum hood. The pulse may have more than Information about quantum-cryptographic products can be found at the Web sites of memory capable of actually storing qu- one photon. An eavesdropper could, in id Quantique (idquantique.com) and MagiQ bits without corrupting them before they theory, steal an extra photon and use it Technologies (magiqtech.com).

By Roy F. Baumeister, Jennifer D. Campbell, Joachim I. Krueger and Kathleen D. Vohs

eople intuitively recognize the importance of self- Boosting people’s sense esteem to their psychological health, so it isn’t particularly remarkable that most of us try to protect and of self-worth has become enhance it in ourselves whenever possible. What is remarkable is that attention to self-esteem has become a national preoccupation. a communal concern, at least for Americans, who see Yet surprisingly, research Pa favorable opinion of oneself as the central psychological source from which all manner of positive outcomes spring. The corol- shows that such efforts are lary, that low self-esteem lies at the root of individual and thus societal problems and dysfunctions, has sustained an ambitious of little value in fostering social agenda for decades. Indeed, campaigns to raise people’s academic progress or sense of self-worth abound. Consider what transpired in California in the late 1980s. preventing undesirable behavior Prodded by State Assemblyman John Vasconcellos, Governor George Deukmejian set up a task force on self-esteem and personal and social responsibility. Vasconcellos argued that raising self-esteem in young people would reduce crime, teen pregnancy, drug abuse, school underachievement and pollution. At one point, he even expressed the hope that these efforts would one day help balance the state budget, a prospect predicated on the observation that people with high self-regard earn more than others and thus pay more in taxes. Along with its other activities, the task force assembled a team of scholars to survey the relevant literature. The results appeared in a 1989 volume entitled The Social Importance

of Self-Esteem, which stated that “many, if not most, of the major MELISSA SZALKOWSKI

84 SCIENTIFIC AMERICAN JANUARY 2005 COPYRIGHT 2004 SCIENTIFIC AMERICAN, INC. COPYRIGHT 2004 SCIENTIFIC AMERICAN, INC. problems plaguing society have roots in the low self-esteem of off. Consider, for instance, research on the relation between many of the people who make up society.” In reality, the report self-esteem and physical attractiveness. contained little to support that assertion. Several studies have explored correlations between these The California task force disbanded in 1995, but a non- qualities, generally ﬁ nding clear positive links when people proﬁ t organization called the National Association for Self- rate themselves on both properties. It seems plausible that Esteem (NASE) has picked up its mantle, aiming (according to physically attractive people would end up with high self- its mission statement) to “promote awareness of and provide esteem because they are treated more favorably than unat- Some findings even suggest that artificially boosting self-esteem may lower subsequent academic performance.

vision, leadership and advocacy for improving the human con- tractive ones—being more popular, more sought after, more dition through the enhancement of self-esteem.” Vasconcellos, valued by lovers and friends, and so forth. But it could just as now a California state senator, is on the advisory board. well be that those who score highly on self-esteem scales by Was it reasonable for leaders in California to start fashion- claiming to be wonderful people all around also boast of being ing therapies and social policies without supportive data? Per- physically attractive. haps so. After all, practicing psychologists and lawmakers In 1995 Edward F. Diener and Brian Wolsic of the Univer- must deal with the problems facing them, even before all the sity of Illinois and Frank Fujita of Indiana University South relevant research is done. But one can draw on many more Bend examined this possibility. They obtained self-esteem studies now than was the case 15 years ago, enough to assess scores from a broad sample of the population and then photo- the value of self-esteem in several spheres. Regrettably, those graphed everybody, presenting these pictures to a panel of judg- who have been pursuing self-esteem-boosting programs, in- es, who evaluated the subjects for attractiveness. Ratings based cluding the leaders of NASE, have not shown a desire to ex- on full-length photographs showed no signifi cant correlation amine the new work, which is why the four of us recently came with self-esteem. Head-and-shoulders close-ups fared slightly together under the aegis of the American Psychological Society better, but even this fi nding is dubious, because individuals to review the scientifi c literature. with high self-esteem might take particular care to present themselves well, such as by wearing attractive clothing and In the Eye of the Beholder jewelry. The 1995 study suggests as much: when the judges gauging the value of self-esteem requires, fi rst of all, a were shown pictures of just the participants’ unadorned faces, sensible way to measure it. Most investigators just ask people the modest correlation between attractiveness and self-esteem what they think of themselves. Naturally enough, the answers fell to zero. In that same investigation, however, self-reported are often colored by the common tendency to want to make physical attractiveness was found to have a strong correlation oneself look good. Unfortunately, psychologists lack any bet- with self-esteem. Clearly, those with high self-esteem are gor- ter method to judge self-esteem, which is worrisome because geous in their own eyes but not necessarily so to others. similar self-ratings of other attributes often prove to be way This discrepancy should be sobering. What seemed at fi rst to be a strong link between physical good looks and high self-esteem turned out to be nothing more than a pattern of Overview/Self-Esteem consistency in how favorably people rate themselves. A paral- ■ Self-esteem is viewed as a communal problem for lel phenomenon affects those with low self-esteem, who are Americans, who worry that inadequate self-esteem leads prone to fl occinaucinihilipilifi cation, a highfalutin word to various undesirable behaviors. (among the longest in the Oxford English Dictionary) but ■ Bullies, contrary to popular perception, do not typically one that we can’t resist using here, it being defi ned as “the suffer from low self-esteem. Neither do those who action or habit of estimating as worthless.” That is, people become sexually active at an early age, nor do those with low self-esteem are not merely down on themselves; prone to abusing alcohol or illicit drugs. they are negative about everything. ■ Raising self-esteem is not likely to boost performance in This tendency has certainly distorted some assessments. school or on the job. For example, psychologists once thought that people with low ■ People with high self-esteem tend to show more initiative self-esteem were especially prejudiced. Early studies, in which and appear to be signifi cantly happier than others. subjects simply rated groups to which they did not belong, seemingly confi rmed that notion, but thoughtful scholars, such

86 SCIENTIFIC AMERICAN JANUARY 2005 COPYRIGHT 2004 SCIENTIFIC AMERICAN, INC. as Jennifer Crocker of the University of Michigan at Ann Ar- ic suggests that having a good dollop of self-esteem would bor, questioned this conclusion. After all, if people rate them- enhance striving and persistence in school, while making a selves negatively, it is hardly proper to label them as prejudiced student less likely to succumb to paralyzing feelings of incom- for rating people not like themselves similarly. When one uses petence or self-doubt. Early work showed positive correla- the difference between the subjects’ assessments of their own tions between self-esteem and academic performance, lending group and their ratings of other groups as the yardstick for bias, credence to this notion. Modern efforts have, however, cast the fi ndings are reversed: people with high self-esteem appear doubt on the idea that higher self-esteem actually induces to be more prejudiced. Floccinaucinihilipilifi cation also raises students to do better. the danger that those who describe themselves disparagingly Such inferences about causality are possible when the sub- may describe their lives similarly, thus furnishing the appear- jects are examined at two different times, as was the case in ance that low self-esteem has unpleasant outcomes. 1986 when Sheila M. Pottebaum, Timothy Z. Keith and Stew- Given the often misleading nature of self-reports, we set up art W. Ehly, all then at the University of Iowa, tested more our review to emphasize objective measures wherever possi- than 23,000 high school students, fi rst in the 10th and again ble—a requirement that greatly reduced the number of relevant in the 12th grade. They found that self-esteem in 10th grade studies (from more than 15,000 to about 200). We were also is only weakly predictive of academic achievement in 12th mindful to avoid another fallacy: the assumption that a cor- grade. Academic achievement in 10th grade correlates with relation between self-esteem and some desired behavior estab- self-esteem in 12th grade only trivially better. Such results, lishes causality. Indeed, the question of causality goes to the which are now available from multiple studies, certainly do heart of the debate. If high self-esteem brings about certain not indicate that raising self-esteem offers students much ben- positive outcomes, it may well be worth the effort and expense efi t. Some fi ndings even suggest that artifi cially boosting self- of trying to instill this feeling. But if the correlations mean esteem may lower subsequent performance [see illustration simply that a positive self-image is a result of success or good on page 89]. behavior—which is, after all, at least as plausible—there is Even if raising self-esteem does not foster academic prog- little to be gained by raising self-esteem alone. We began our ress, might it serve some purpose later, say, on the job? Appar- two-year effort to sort out the issue by reviewing studies relat- ently not. Studies of possible links between workers’ self-regard ing self-esteem to academic performance. and job performance echo what has been found with school- work: the simple search for correlations yields some suggestive School Daze results, but these do not show whether a good self-image leads at the outset, we had every reason to hope that boosting to occupational success, or vice versa. In any case, the link is self-esteem would be a potent tool for helping students. Log- not particularly strong. SELF-ESTEEM AND ACADEMIC ACHIEVEMENT In an attempt to gauge whether high self-esteem leads to good academic performance, researchers surveyed thousands of high school students in their sophomore and senior years. The correlation between self-esteem sophomore year and academic performance senior year proved to be about the same as the correlation between academic performance sophomore year and self-esteem senior year. Thus it is hard to know which causes which—or whether some third factor gives rise to both high self-esteem and superior academic achievement.

Correlation of 10th-grade self-esteem with 12th-grade achievement

Correlation of 10th-grade achievement with 12th-grade self-esteem

Correlation of 10th-grade self-esteem with 12th-grade self-esteem

Correlation of 10th-grade achievement with 12th-grade achievement

0.0 0.2 0.4 0.6 0.8 1.0 Degree of Correlation

SOURCE: S. M. Pottebaum, T. Z. Keith and S. W. Ehly in Educational Research, Vol. 79, pages 140–144; 1986. STONE+ STONE+

Managing conﬂ icts Self-rated

Skills NS Roommate- rated Providing emotional support NS

Disclosing information about self NS

Asserting self

Interpersonal Relationship in response to objectionable behaviors by others NS A study of college students revealed strong links between self- esteem and various interpersonal skills—when the subjects Initiating rated themselves. Using skill ratings provided by their relationships roommates provided a different picture: for four of the ﬁ ve skills surveyed, the correlations with self-esteem dropped to levels 0.0 0.2 0.4 0.6 0.8 1.0 that were not signiﬁ cant (NS) statistically. Nevertheless, the Degree of Correlation with High Self-Esteem connection between self-esteem and prowess in initiating relationships remained reasonably robust, as one might expect. SOURCE: D. Buhrmester, W. Furman, M. T. Wittenberg and H. T. Reis in Journal of Personality and Social Psychology, Vol. 55, pages 991–1008; 1988.

The failure to contribute signifi cantly at school or at the A few other methodologically sound studies have found offi ce would be easily offset if a heightened sense of self-worth that the same is true for adults. In one of these investigations, helped someone to get along better with others. Having a conducted in the late 1980s, Duane P. Buhrmester, now at the good self-image might make someone more likable insofar as University of Texas at Dallas, and three colleagues reported people prefer to associate with confi dent, positive individuals that college students with high levels of self-regard claimed to and generally avoid those who suffer from self-doubts and be substantially better at initiating relationships, better at dis- insecurities. closing things about themselves, better at asserting themselves People who regard themselves highly generally state that in response to objectionable behaviors by others, better at pro- they are popular and rate their friendships as being of superior viding emotional support and better even at managing inter- quality to those described by people with low self-esteem, who personal confl icts. Their roommates’ ratings, however, told a report more negative interactions and less social support. But different story. For four of the fi ve interpersonal skills sur- as Julia Bishop and Heidi M. Inderbitzen-Nolan of the Univer- veyed, the correlation with self-esteem dropped to near zero. sity of Nebraska–Lincoln showed in 1995, these assertions do The only one that remained statistically signifi cant was with not refl ect reality. The investigators asked 542 ninth-grade the subjects’ ability to initiate new social contacts and friend- students to nominate their most-liked and least-liked peers, ships. This does seem to be one sphere in which confi dence and the resulting rankings displayed no correlation whatso- indeed matters: people who think that they are desirable and ever with self-esteem scores. attractive should be adept at striking up conversations with strangers, whereas those with low self-esteem presumably shy ROY F. BAUMEISTER, JENNIFER D. CAMPBELL, JOACHIM I. KRUEGER away from initiating such contacts, fearing rejection. and KATHLEEN D. VOHS collaborated on a more technical paper One can imagine that such differences might infl uence a on self-esteem published in Psychological Science in the Public person’s love life, too. In 2002 Sandra L. Murray of the Uni- Interest [see “More to Explore,” on page 91]. Baumeister, for- versity at Buffalo and four colleagues found that people low in merly a professor of psychology at Case Western Reserve Uni- self-esteem tend to distrust their partners’ expressions of love versity, became Eppes Professor of Psychology at Florida State and support, acting as though they are constantly expecting THE AUTHORS University in 2003. Campbell is emeritus professor of psychol- rejection. Thus far, however, investigators have not produced ogy at the University of British Columbia in Vancouver. Krueger evidence that such relationships are especially prone to dis-

is professor of psychology at Brown University. Vohs holds the solve. In fact, high self-esteem may be the bigger threat: as Corbis Canada Research Chair in Marketing Science and Consumer Psy- Caryl E . Rusbult, Gregory D. Morrow and Dennis J. Johnson, chology in the Sauder School of Business at the University of all then at the University of Kentucky, showed back in 1987,

British Columbia. those who think highly of themselves are more likely than oth- FARIS RANDY

88 SCIENTIFIC AMERICAN JANUARY 2005 COPYRIGHT 2004 SCIENTIFIC AMERICAN, INC. ers to respond to problems by severing relations and seeking If not sex, then how about alcohol or illicit drugs? Abuse of other partners. these substances is one of the most worrisome behaviors among young people, and many psychologists once believed that Sex, Drugs, Rock ’n’ Roll boosting self-esteem would prevent such problems. The thought how about teenagers? How does self-esteem, or the was that people with low self-esteem turn to drinking or drugs lack thereof, infl uence their love life, in particular their sexu- for solace. The data, however, do not consistently show that al activity? Investigators have examined this subject exten- low adolescent self-esteem causes or even correlates with the sively. All in all, the results do not support the idea that low abuse of alcohol or other drugs. In particular, in a large-scale self-esteem predisposes young people to more or earlier sex- study in 2000, Rob McGee and Sheila M. Williams of the Uni- ual activity. If anything, those with high self-esteem are less versity of Otago Medical School in New Zealand found no inhibited, more willing to disregard risks and more prone to correlation between self-esteem measured between ages nine engage in sex. At the same time, bad sexual experiences and and 13 and drinking or drug use at age 15. Even when fi ndings unwanted pregnancies appear to lower self-esteem. do show links between alcohol use and self-esteem, they are MIXED MESSAGES A 1999 study by Donelson R. Forsyth and Natalie A. Kerr an e-mail message designed to boost their self-esteem of Virginia Commonwealth University suggests that attempts (such as the example shown at left). Those in the second group to boost self-esteem among struggling students may received a message intended to instill a sense of personal backfi re. Here the subjects were students taking a college responsibility for their academic performance (right). course in psychology. By the end of the course, the average grade for students Those getting grades of D or F were divided into two in the fi rst group dropped below 50 percent—a failing grade. groups, arranged initially to have the same grade-point The average for students in the second group was average. Each week, students in the fi rst group received 62 percent—a D minus, which is poor but still passing.

Group 1 Group 2

WHAT CAUSES GOOD AND BAD GRADES? WHAT CAUSES GOOD AND BAD GRADES? Past research suggests that when students get back Past research suggests that when students get back their their tests, they tend to lose conﬁ dence: they say things tests, they tend to blame poor scores on external factors: like “I can’t do this,” or “I’m worthless,” or “I’m not as they say things like “the test was too hard,” or “the prof good as other people in college.” didn’t explain that,” or “the questions are too picky.”

Other studies suggest, though, that students who have Other studies suggest, though, that students who take high self-esteem not only get better grades, but they responsibility for their grades not only get better grades, remain self-conﬁ dent and assured. but they also learn that they, personally, can control the grades they get. In fact, in one study researchers had students write down what “went through their minds” when they were trying to In fact, in one study researchers had students write down get better grades. Students who improved with each test what “went through their minds” when they were trying to were thinking: get better grades. Students who improved with each test “I can be proud of myself.” were thinking: “I can do this.” “I need to work harder.” “I am better than most of the other people in this “I can learn this material if I apply myself.” school.” “I can control what happens to me in this class.” “I am satisﬁ ed with myself.” “I have what it takes to do this.”

Students who did not improve were thinking: Students who did not improve were thinking: “I’m ashamed of myself.” “It’s not my fault.” “I don’t deserve to be in college.” “This test was too hard.” “I’m worthless.” “I’m not good at this.”

BOTTOM LINE: Hold your head—and your self-esteem—high. BOTTOM LINE: Take personal control of your performance.

www.sciam.com SCIENTIFIC AMERICAN 89 COPYRIGHT 2004 SCIENTIFIC AMERICAN, INC. mixed and inconclusive. A few studies have shown that high ers may use it to cope with or escape from chronic unhappi- self-esteem is associated with frequent alcohol consumption, ness. The overall result is that no categorical statements can but another suggests the opposite. We did fi nd, however, some be made. The same is true for tobacco use, where our study- evidence that low self-esteem contributes to illicit drug use. by-study review uncovered a preponderance of results that In particular, Judy A. Andrews and Susan C. Duncan of the show no infl uence. The few positive fi ndings we unearthed Oregon Research Institute found in 1997 that declining levels could conceivably refl ect nothing more than self-report bias. of academic motivation (the main focus of their study) caused Another complication that also clouds these studies is that self-esteem to drop, which in turn led to marijuana use, al- the category of people with high self-esteem contains indi- though the connection was rather weak. viduals whose self-opinions differ in important ways. Yet in Interpretation of the fi ndings on drinking and drug abuse most analyses, people with a healthy sense of self-respect are, is probably complicated by the fact that some people approach for example, lumped with those feigning higher self-esteem the experience out of curiosity or thrill seeking, whereas oth- than they really feel or who are narcissistic. Not surprisingly, SELF-ESTEEM AND HAPPINESS

Around the world, a person’s overall satisfaction Bangladesh (129) with life tends to go hand in hand with his or her Tanzania (240) level of self-esteem, as shown by the high degree India (262) of correlation between the two. Note that in Kenya (347) Correlation of most countries overall life satisfaction correlates Egypt (672) self-esteem better with self-esteem than with financial with overall life satisfaction. Exceptions tend to be countries with Philippines (724) satisfaction low per capita GDP (bracketed values). Thailand (810) Correlation of Cameroon (845) ﬁ nancial satisfaction Turkey (1,210) with overall life Jordan (1,690) satisfaction Chile (1,920) Korea (1,978) Brazil (2,032) Mexico (2,154) South Africa (2,424) Yugoslavia (2,500) Greece (3,932) Norway (4,007) Spain (4,780) Israel (5,420) Puerto Rico (5,477) Singapore (6,653) New Zealand (7,709) Austria (9,218) Netherlands (9,869) Japan (10,154) Bahrain (10,041) Finland (10,725) Germany (11,403) Canada (12,284) U.S. (14,172) 0.0 0.2 0.4 0.6 0.8 1.0 Degree of Correlation SOURCE: E. Diener and M. Diener in Journal of Personality and Social Psychology, Vol. 68, pages 653–663; 1995. MELISSA SZALKOWSKI

90 SCIENTIFIC AMERICAN JANUARY 2005 COPYRIGHT 2004 SCIENTIFIC AMERICAN, INC. the results of such investigations may produce weak or contra- possible that happiness, in the sense of a temperament or dis- dictory fi ndings. position to feel good, induces high self-esteem. Second, it must be recognized that happiness (and its op- Bully for You posite, depression) has been studied mainly by means of self- for decades, psychologists believed that low self-esteem report, and the tendency of some people toward negativity was an important cause of aggression. One of us (Baumeis- may produce both their low opinions of themselves and unfa- ter) challenged that notion in 1996, when he reviewed as- vorable evaluations of other aspects of life. In other instances, sorted studies and concluded that perpetrators of aggression we were suspicious of self-reports, yet here it is not clear what generally hold favorable and perhaps even infl ated views of could replace such assessments. An investigator would indeed themselves. be hard-pressed to demonstrate convincingly that a person Take the bullying that goes on among children, a common was less (or more) happy than he or she supposed. Clearly, form of aggression. Dan Olweus of the University of Bergen objective measures of happiness and depression are going to People with high self-esteem are significantly happier than others. They are also less likely to be depressed. was one of the fi rst to dispute the notion that under their be diffi cult if not impossible to obtain, but that does not mean tough exteriors, bullies suffer from insecurities and self- self-reports should be accepted uncritically. doubts. Although Olweus did not measure self-esteem direct- What then should we do? Should parents, teachers and ly, he showed that bullies reported less anxiety and were more therapists seek to boost self-esteem wherever possible? In the sure of themselves than other children. Apparently the same course of our literature review, we found some indications applies to violent adults, as Baumeister discussed in these that self-esteem is a helpful attribute. It improves persistence pages a few years ago [see “More to Explore,” below]. in the face of failure. And individuals with high self-esteem After coming to the conclusion that high self-esteem does sometimes perform better in groups than do those with low not lessen a tendency toward violence, that it does not deter self-esteem. Also, a poor self-image is a risk factor for certain adolescents from turning to alcohol, tobacco, drugs and sex, eating disorders, especially bulimia—a connection one of us and that it fails to improve academic or job performance, we (Vohs) and her colleagues documented in 1999. Other effects got a boost when we looked into how self-esteem relates to are harder to demonstrate with objective evidence, although happiness. The consistent fi nding is that people with high self- we are inclined to accept the subjective evidence that self- esteem are signifi cantly happier than others. They are also less esteem goes hand in hand with happiness. likely to be depressed. So we can certainly understand how an injection of self- One especially compelling study was published in 1995, esteem might be valuable to the individual. But imagine if a after Diener and his daughter Marissa, now a psychologist at heightened sense of self-worth prompted some people to de- the University of Utah, surveyed more than 13,000 college mand preferential treatment or to exploit their fellows. Such students, and high self-esteem emerged as the strongest factor tendencies would entail considerable social costs. And we have in overall life satisfaction. In 2004 Sonja Lyubomirsky, Chris found little to indicate that indiscriminately promoting self- Tkach and M. Robin DiMatteo of the University of Califor- esteem in today’s children or adults, just for being themselves, nia at Riverside reported data from more than 600 adults offers society any compensatory benefi ts beyond the seductive ranging in age from 51 to 95. Once again, happiness and self- pleasure it brings to those engaged in the exercise. esteem proved to be closely tied. Before it is safe to conclude that high self-esteem leads to happiness, however, further re- MORE TO EXPLORE search must address the shortcomings of the work that has The Social Importance of Self-esteem. Edited by Andrew M. Mecca, been done so far. Neil J. Smelser and John Vasconcellos. University of California First, causation needs to be established. It seems possible Press, 1989. that high self-esteem brings about happiness, but no research Violent Pride. Roy F. Baumeister in Scientifi c American, Vol. 284, No. 4, has shown this outcome. The strong correlation between self- pages 96–101; April 2001. Does High Self-Esteem Cause Better Performance, Interpersonal esteem and happiness is just that—a correlation. It is plausible Success, Happiness, or Healthier Lifestyles? Roy F. Baumeister, that occupational, academic or interpersonal successes cause Jennifer D. Campbell, Joachim I. Krueger and Kathleen D. Vohs in both happiness and high self-esteem and that corresponding Psychological Science in the Public Interest, Vol. 4, No. 1, pages 1–44; failures cause both unhappiness and low self-esteem. It is even May 2003. www.sciam.com SCIENTIFIC AMERICAN 91 COPYRIGHT 2004 SCIENTIFIC AMERICAN, INC. WORKINGKNOWLEDGE

KEYLESS ENTRY Open Sesame

You exit a busy store, point your key fob across the Auto manufacturer programs a car’s receiver and a key fob with crowded parking lot, press a button and “Pop!”— 1 a software algorithm that will generate a unique 32-bit number your car door unlocks. How does the car know it’s each time they are activated. The number is created along a preset you? And why don’t other cars open, too? pattern determined by a formula that only that vehicle and fob Most new vehicles offer what the industry calls share, so one person's fob can't open another's car. remote keyless entry. Manufacturers program a microprocessor in each car and in its dedicated key fob with an algorithmic formula that generates a secret, encrypted code that changes each time a button is Driver presses a fob button, and it pressed [see illustration]. Each formula is unique, so 2 transmits a stream of 64-bit data one person’s fob cannot open any other vehicle. Cur- packets. The receiver captures one rent-day garage door openers work similarly. “The full packet comprising a serial number, scheme has been around for 10 years and has proven a new secret number and a command very secure,” says Fanie Duvenhage, product mar- (unlock door). If the serial number keting manager at Microchip Technology, a Chan- matches, the receiver also dler, Ariz., ﬁ rm whose code-generating processors generates a new secret number. run the majority of U.S. automotive fobs. “We have If the numbers agree, the not seen any successful attack on the algorithm.” receiver instructs the car’s Success has spawned even greater convenience controller to open the door. and protection. In “passive keyless entry,” a driver The number is created with standing beside a door begins to lift its handle, and encryption technology a transceiver inside the car compares code with a so a thief cannot decipher key fob or smart card in the driver’s pocket or hand- it if he manages to capture bag—handy for someone carrying an armful of gro- the transmission with ceries or packages. “Immobilization” systems will a radio scanner. not allow a car to start after a key is inserted into the ignition unless a chip built into the key head provides the right code to a chip inside the ignition housing. In European countries that have mandated immobilizers in new cars, theft of current models has decreased by more than 50 percent. INSIDE Immobilizer and passive entry communications THE FOB take place at the relatively low frequency of 125 kilohertz. Remote keyless systems tap much higher frequencies, typically 315 megahertz in the U.S. and Japan, in part to span a parking lot or front lawn. Capacitor European manufacturers have been using 433 mega- Transmitter hertz, notes Alec Makdessian, business manager at Microprocessor integrated-circuits maker Maxim Integrated Prod- ucts in Sunnyvale, Calif., “but they are moving up to Button pads 868 megahertz because the lower bands are becom- Battery ing congested.” About two million new keyless gadgets worldwide add to the saturation every year.

—Mark Fischetti PRODUCTS INTEGRATED MAXIM INC.; COILCRAFT, SOURCES: VELASCO; SAMUEL

92 SCIENTIFIC AMERICAN JANUARY 2005 COPYRIGHT 2004 SCIENTIFIC AMERICAN, INC. ➤ TIRES: Low tire pressure can lead to dangerous steering or a the street and open neighbors’ doors. By the 1970s the “clicker” blowout. Recent federal law mandates that new vehicles must and the door controller each had an integrated circuit switch with eventually be equipped with tire-pressure monitoring systems. eight little pins that were manually set to agree, providing one of The leading option, already offered on some models, is a sensor 256 possible codes—better, but still not very secure. Today’s open- housed in a fob inside a tire, behind the valve stem. If pressure ers use the same electronic algorithms as auto key fobs do; a 32-bit drops 25 percent below recommended inﬂ ation, the fob’s battery- code offers more than four billion possible combinations. powered radio transmitter (much like a key fob’s) alerts the car’s computer, which lights a warning icon on the dashboard. ➤ HOUSES, TOO: Some homes now have keyless dead bolts that com- municate with a key fob. They typically display a red light that indi- ➤ GARAGES: The ﬁ rst garage door openers appeared in the 1950s. cates when a door is locked. No more fumbling for keys when hands

DID YOU KNOW...DID They sent a simple “open” or “close” command over a single fre- are full or scraping for the keyhole in the dark. Just be sure the but- quency. As they slowly proliferated, one person could drive down ton isn’t depressed on that spare fob hidden under the ﬂ owerpot.

If a fob is pressed INSIDE THE 3 while too far from RECEIVER the car, when it is Receiver pressed again the new secret number will be further along the pattern than the number the receiver will generate. The receiver waits for the driver to press the fob again. If Antenna the increment matches what the receiver’s Micro- processor formula predicts would Power be generated, the from car receiver accepts the fob as the correct one, updates its memory and executes the command. Receiver

IMMOBILIZER Driver inserts a key into the ignition. Windings emit a magnetic ﬁ eld that induces current in the key’s Smart transponder. The ignition microprocessor fob generates a secret number. If the transponder can match it, the controller allows the ignition to start.

Transceiver Transponder Windings Controller PASSIVE KEYLESS ENTRY When a person lifts a door handle, the car’s transceiver broadcasts a radio signal to see if a smart fob is within ﬁ ve feet of the door. If so, the transceiver generates a secret number and challenges the fob to do the same. If it does, the Micro- processor transceiver tells the car’s controller to unlock the door.

Topic was suggested by numerous readers. Send ideas to [email protected]

How Are the Mighty Fallen? THE RISE AND FALL OF MONTANA, MAYA AND OTHER SOCIETIES BY ROBERT S. DESOWITZ

passions. So Diamond the ardent fl y- it, “parasites on farmers,” who could no COLLAPSE: HOW fi sherman, defender of ecological pris- longer produce surplus food on their SOCIETIES CHOOSE tineness, sympathetic friend of the farm- now barren, treeless land. The Maya be- TO FAIL OR SUCCEED ing “locals” has come to the sad conclu- gan to go into decline about A.D. 1000 By Jared Diamond Viking, 2005 sion that Montana is going to the dogs. and said goodbye to the world about ($29.95) Once one of the richest states of the 1675, mopped up by the Spanish. union, it now ranks among the poorest, Diamond argues that the isolated is- having squandered its nonrenewable land societies suffered a similar fate to According to mineral resources and savagely over- the Anasazi and Maya for similar rea- scripture, “How logged its forests. Maybe worst of all, sons. Pitcairn Island, Easter Island and are the mighty fallen in the midst of bat- some cad put pike into the trout waters. Greenland all collapsed after the settlers tle” (II Samuel 1:25). To war, Jared Dia- Although Montana is not about to had exhausted the fragile food and tim- mond in his new book, Collapse: How fall off the map, leaving us with 49 states, ber resources. Deforestation was partic- Societies Choose to Fail or Succeed, the elements responsible for its decline ularly critical; after the larger trees were adds self-infl icted environmental degra- are also responsible for societies that harvested, nothing was left to make the dation, climate change, disastrous trad- have fallen by the wayside. Diamond’s seagoing canoes needed for voyaging to ing relations, and unwise responses to central proposition is that wherever these other sources of food and material and societal problems. In his earlier, Pulitzer globally disparate societies failed the for recruiting new people, especially Prize–winning Guns, Germs and Steel, chief cause had been anthropogenic eco- wives, into their dwindling, interbreed- Diamond, a professor of geography at logical devastation, especially deforesta- ing populations. the University of California at Los An- tion, imposed on ecosystems of limited In these historical accounts of fallen

geles, celebrated the rise of communities resources. Those other western Ameri- societies, untrammeled population Corbis and nations despite microbial and self- cans, the Anasazi, settled in the New growth did not play a signiﬁ cant role. imposed adversities. Mexico area about A.D. 600. There they Not until the section on modern societies Collapse is the downside of those built spectacular cliff housing, worked with modern troubles does Diamond in-

dynamics, the societies that didn’t make their marginal agricultural land, and voke Malthus, offering Rwanda as the ROGERS W. JOEL it, barely made it, or are destined, as chopped down all the trees without any Diamond sees it, for the fall. In this ex- plans for reforestation. Starving to the haustively researched new book, he pre- desperate point of cannibalism, wracked sents carefully detailed case histories of by internecine warfare, they met their failed societies—islands in warmish wa- end some 600 years later. ters (Easter, Pitcairn, Haiti), an island in To the south, the Maya mostly had it coolish waters (Greenland), a continen- all: technological knowledge to build ar- tal semidesert (the Anasazi of the South- chitecturally wonderful cities, writing, west U.S.), a continental tropical forest and crops of corn. What they did not (the Maya of Mexico). have were large domestic animals, or the Diamond begins with the failed state foresight to replant after they clear-cut of Montana. Montana? Well, a Pulitzer forests, or the political sense to refrain PATTERN OF CATASTROPHE in the collapse of past civilizations included deforestation and Prize–winning tenured professor can from inter-city warfare. Mayan soldiers other environmental degradation. take the liberty of giving priority to his and city dwellers were, as Diamond puts

prime Malthusian model of too many the forests of vulnerable states such as clear choice to survive, let alone succeed. people with too little land. He makes an Papua New Guinea). The Dominican Collapse is a big book, 500-plus pag- unconventional interpretation of the sav- Republic preserved its forests and pros- es. It may well become a seminal work, age Rwandan confl ict. It was not a mutu- pered. Its neighbor Haiti ravished both although its plea for societal survival ally genocidal affair propelled by ancient land and forests. And look what hap- through ecological conservation is rath- hatreds. At the village level the Hutu and pened to them. er like preaching to the choir. It is not a Tutsi had lived together amicably—until I wrote these last words while fl ying page-turner, especially for slow readers geometric population growth far exceed- home from a National Academy of Sci- of short attention span (like this reviewed the arithmetic increase in land and ences meeting called to reconsider er). Some of Diamond’s “case studies” improved agricultural technology, ful- bringing back that contentious, effec- may be overkilled by overdetail. The last fi lling the thesis of Malthus’s 1798 Essay tive and dirt-cheap chemical, DDT. section, on practical lessons, seems dis- on the Principle of Population. The bru- Now the choice will have to be made connected from the central Collapse tal killing was, according to Diamond, between the ultraconservationists’ pro- story and almost constitutes a separate primarily over your neighbor’s land, not hibition of DDT and the equally ardent book. But, having discharged the re- his tribal affi liation. arguments of a new coterie of American viewer’s obligation to be critical, my rec- As the book’s subtitle suggests, there scientists who are demanding the return ommendation would definitely be to are societies that have come to success by of DDT to try to halt the carnage of the read the book. It will challenge and right thought and action. The Japanese, malaria parasite, which kills two million make you think—long after you have for example, saw the light and preserved to three million children and pregnant turned that last 500th-plus page. and replanted their forests (although women every year. Sorry, Professor Dia- they have not renounced their national mond, even in our time of enlightened sci- Robert S. Desowitz is emeritus wood esthetic; the trees now come from ence, societies don’t always have an easy, professor of tropical medicine at the

96 SCIENTIFIC AMERICAN JANUARY 2005 COPYRIGHT 2004 SCIENTIFIC AMERICAN, INC. University of Hawaii. He is author of ﬁ ve books on ecological and political issues relating to infectious diseases, the most recent being Federal Bodysnatchers and the New Guinea Virus (W. W. Norton, 2003). THE EDITORS RECOMMEND BOOKS ON EINSTEIN A shelfful of books greets the centennial of Albert Einstein’s “miracle year,” which witnessed the theory of special relativity and four other seminal papers. Here is a sampling of the books our staff enjoyed.

EINSTEIN’S COSMOS: HOW ALBERT EINSTEIN’S VISION TRANSFORMED OUR UNDERSTANDING OF SPACE AND TIME By Michio Kaku. W. W. Norton, 2004 ($22.95) Thanks to Kaku’s insight (he is a theoretical physicist) and his ﬂ air for explaining dense scientific concepts (he is a best-selling author), this brief book weaves Einstein’s life and work into a seamless, hard-to-put-down narrative. The organizing metaphor is how Einstein thought in terms of simple physical pictures—speeding trains, falling elevators, moving clocks. Excellent for the neophyte or readers who want to refresh their knowledge about Einstein without being talked down to or bored.

EINSTEIN’S CLOCKS, POINCARÉ’S MAPS: EMPIRES OF TIME By Peter Galison. W. W. Norton, 2004 ($14.95, paperbound) Two scientists closed in on one groundbreak- book,” it is all of the above, but it is not for the on the frontier of the invisible, the search for ing theory. Poincaré posited something so intellectually faint of heart. the next level of scientifi c data—evidence we close to Einstein’s theory of relativity that it can’t see. is surprising in retrospect he did not take the THE INVISIBLE CENTURY: EINSTEIN, FREUD, fi nal step. The story is told in this new (paper- AND THE SEARCH FOR HIDDEN UNIVERSES EINSTEIN DEFIANT: GENIUS VERSUS GENIUS bound) edition of a book that appeared in By Richard Panek. Viking, 2004 ($24.95) IN THE QUANTUM REVOLUTION 2003. Described then as “absolutely bril- A less likely pairing emerges in this book— By Edmund Blair Bolles. Joseph Henry liant,” “a stroke of genius,” “fresh, idiosyn- Einstein and Sigmund Freud. Although they Press, 2004 ($27.95) cratic,” and “meticulously detailed ... per- met just once and didn’t know what to make Bolles intertwines a rich combination of sci- haps the most sophisticated history of sci- of each other’s work, Einstein and Freud entifi c explanation and literary drama, paint-

EMILY HARRISON EMILY ence ever attempted in a popular science became the foremost proponents of research ing a picture of Einstein’s persona, the Euro-

pean mind-set, and the soap opera of quan- who ran away with his brain. From absent- a surprising number of new quotes to her tum physics. The focus is on Einstein’s battle mindedness to Zionism, Fox and Keck offer quirky biography for the impatient reader. for causality, the idea that every event has a sharp, bite-size pieces of Einstein-related Most quotes are ordinary statements that cause and can thus be predicted. people, concepts and quirks in a fun book convey a sense of Einstein’s character rather ideal for trivia lovers and the science-wary. than his mind-boggling intelligence. ALBERT EINSTEIN’S VISION: REMARKABLE DISCOVERIES THAT SHAPED THE EINSTEIN ALMANAC THE COMPLETE IDIOT’S GUIDE TO MODERN SCIENCE By Alice Calaprice. Johns Hopkins UNDERSTANDING EINSTEIN By Barry Parker. Prometheus Books, University Press, 2004 ($24.95) By Gary F. Moring. Second edition. Alpha 2004 ($28) In a complete, concise guide, the author (who Books (Penguin), 2004 ($18.95) Parker follows Einstein’s train of thought into was in-house editor of the Princeton Univer- While the complete idiot may think that Ein- the 20th century, examining the develop- sity Press series The Collected Papers of stein = relativity, Moring goes back as far as ments that resulted from his works. The book Albert Einstein) sets brief descriptions of the ancient Greeks to set a solid stage for provides readers with enough information to 300 of Einstein’s publications into the con- Einstein’s myriad accomplishments in ﬁ elds recognize current buzzwords but not neces- text of concurrent events in his personal life, ranging from physics to philosophy. The sarily to understand them. the world in general, and the realm of physi- book’s explanations are complete enough to cal science. both satisfy the reader and pacify the scien- EINSTEIN A TO Z tist, and the cheeky writing style is amusing By Karen C. Fox and Aries Keck. John Wiley, THE EXPANDED QUOTABLE EINSTEIN without being annoying. 2004 ($17.95) Collected and edited by Alice Calaprice. Every Einstein book talks about relativity, Princeton University Press, 2000 ($19.95) The books reviewed are available for but not many tell you about the mortician In her expanded edition, Calaprice has added purchase through www.sciam.com

Captive Audience “TO FERRET” MEANS TO BRING TO LIGHT BY SEARCHING BY STEVE MIRSKY

In October researchers announced in 1. Why did researchers make ferrets dre or C-SPAN’s coverage of Congress. the journal Nature what could prove to watch The Matrix? Answer: Because A surprise for the scientists was that be one of the greatest scientifi c discover- there are some things that rats just watching the movie made an adult ferret ies of all time—the fossil remains of a won’t do. brain’s visual system work only a bit miniature species of humans. The island 2. Why did researchers make ferrets harder than its baseline output. The fer- of Flores, already famous in paleonto- watch The Matrix? Answer: Because rets’ visual neurons were cranking along logical circles for having been home to if they had made ferrets watch The at about 80 percent of capacity even in pygmy elephants, also seems to have en- Matrix Reloaded, animal-rights a completely dark room. “In this frame- couraged the downsizing of a stray groups would have been storming the work,” the researchers write, “ongoing group of Homo erectus who wound up laboratory. activity may not be noise upon which there. Small stature was selected until 3. Why did researchers make ferrets visual responses are superimposed, but adults were just over three feet tall and watch The Matrix? Answer: To get a rather an integral component of sensory deserved to be classifi ed as a new spe- better handle on the nature of the processing.” That thing going bump in cies. Islands, with limited resources, perception of reality. the night is your brain. promote this kind of diminution— Sci- Seriously. The Matrix was an ironic A provocative conjecture is that entifi c American’s offi ces are on the is- choice, because that particular movie most of the brain’s visually related activ- land of Manhattan, and some of us need poses questions about whether what we ity is devoted to continuously manufac- a boost just to type uppercase letters. commonly perceive is objective reality turing its learned representation of the You’ll be able to read a full-length or just an imposed fi ction. But because world—its reality matrix—even in the feature article about the not-quite-full- the investigators were interested in how complete absence of any current stimuli. length people of Flores in our February a brain processes visual stimulation, And new, real-time action is overlaid on issue. But I am forced to abandon my they could have shown the ferrets any- that internal representation. consideration of them at this point in thing other than My Dinner with An- “Because of the high-energy con- favor of a discussion of other research. sumption of baseline neural activity in Because, at the end of September, Na- the brain,” the scientists write, “it would ture published a study in which scien- be ineffi cient to maintain the observed tists made ferrets watch the movie The high level of spontaneous activity unless Matrix. I’ll wait while you read that last it had an essential role in sensory pro- sentence again. cessing.” Perhaps it’s simply easier to Indeed, researchers at the University keep the matrix handy at all times than of Rochester made a dozen ferrets watch to ask the brain to build reality from The Matrix. (The idea of 12 sentient be- scratch every moment. Which leads to ings exposed to bad acting from stiff this parting thought from the great my- guys dressed in cheap suits particularly thologist Joseph Campbell: “Life is like disturbs me, but that’s probably because arriving late for a movie, having to fi g- I was just on jury duty.) Of course, you ure out what was going on without are no doubt wondering why serious sci- bothering everybody with a lot of ques- entists made ferrets watch The Matrix. tions, and then being unexpectedly This question can be answered in three called away before you fi nd out how it

different ways: ends.” Especially if you’re a ferret. VERONSKY FRANK BY PHOTOGRAPH COLLINS; MATT BY ILLUSTRATION

How do computer hackers “get inside” Qa computer? —D. Ikavuka, La Mirada, Calif. Julie J.C.H. Ryan, assistant professor at George Washington usually record the browser being used. The UU could write a University and co-author of Defending Your Digital Assets program that takes advantage of this procedure, making the against Hackers, Crackers, Spies, and Thieves, explains: Web page ask for even more information. With this knowl- Essentially, hackers get inside a computer system by tak- edge in hand, the UU then writes a program that circumvents ing advantage of software or hardware weaknesses that exist the protections in place in the system. in every system. Before explaining how they do this, a few Although you cannot eliminate all possible weaknesses, defi nitions are in order. The term “hacker” is fairly contro- you can take steps to protect against unauthorized access. versial: some use this word to describe those whose intrusions Make sure you have the latest patches for your operating sys- into computer systems push the boundaries of knowledge tem and applications. Create a complex password with letters, without causing intentional harm, whereas “crackers” want numbers and symbolic characters. Consider installing a fi re- to wreak havoc. I prefer “unauthorized user” (UU) for anyone wall program, which blocks unwanted Internet traffi c. Make who engages in unsanctioned computer access. “Getting in- sure your antivirus software is up-to-date and check frequent- side” can mean one of three things: accessing the information ly for new virus defi nitions. Finally, back up your data, so you stored on a computer, surreptitiously using a machine’s pro- can recover important material if anything does happen. cessing capabilities (to send spam, for instance) or capturing information being sent between systems. So how does a UU get inside a computer? The easiest weakness to exploit is a poorly conceived password. Pass- Why do traffi c jams sometimes word-cracking programs can identify dictionary words, seem to appear out of nowhere? names and even common phrases within a matter of minutes. Q — H. Smith, New York City Many of these programs perform a “dictionary attack”: they take the encryption code used by the password system and Benjamin Coifman, assistant professor of electrical and com- encrypt every word in the dictionary. Then the UU plugs in puter engineering at Ohio State University who studies traffic the encrypted words until the password match is found. If a patterns, offers this answer: system has a complex password, the UU could try a “technical Drivers encounter the end of the line in a traffi c jam seem- exploit,” which means using technical knowledge to break ingly out of nowhere because the number of waiting cars could into a computer system (as opposed to nontechnical options stretch several miles away from the original bottleneck. The such as stealing documentation about a system). This is more bottleneck could have arisen because of an accident or because challenging, because the UU must fi rst learn what kind of of features in the roadway, such as a sharp curve, where drivers system the target is and what the system can do. A profi cient must slow down. The difference between the bottleneck’s ca- UU can do this remotely pacity and the demand upstream determines how fast the line by utilizing a hypertext grows. The end of the line typically has the worst conditions transfer protocol (http) because cars there suffer from accumulated delays caused by that gains World Wide the original obstruction, especially since vehicles entering from Web access. Web pages ramps worsen the problem by occupying additional space. Speeds tend to improve as drivers progress, making it easy to miss the actual trouble site when you fi nally pass it.

For a complete text of these and other answers from

scientists in diverse ﬁ elds, visit www.sciam.com/askexpert COLLINS MATT