AI Magazine Volume 19 Number 3 (1998) (© AAAI) Book Review

states that served biological fitness in A Review of ancestral environments.… It is made up of modules for reasoning about how objects, artifacts, living things, How the Mind Works animals, and other human minds work” (pp. 524–525). Pinker chooses to use the word engineering on purpose because he Tapio Elomaa wants to convince the reader that the human mind has really been engi- neered, by evolution, to its present configuration. As evidence of this tele- ological construction, he takes the Steven Pinker’s previous book, the ny anecdotes from movies, literature, universal, complex, well-engineered, widely successful The Language cartoons, and so on, to invigorate the and reproduction-promoting design Instinct (Pinker 1994) forcefully pro- text. All this adds up to a fluent and of, for example, language and stereo moted Noam Chomsky’s idea of a uni- entertaining reading experience. How- vision. According to Pinker, we have versal grammar underlying particular ever, what about the substance? Partly, innate instincts for such abilities natural languages, the innate lan- the research surveyed in this book can because of the many mental modules guage ability of humans, and present- already be considered classical; for that have become a part of our geno- ed a theory of how a language organ example, the extensive coverage of type. could have evolved through Darwini- human stereo vision is mostly based Pinker’s theory of the human mind an natural selection. His provocative on Marr’s (1982) seminal account of stands firmly on two legs: The first one monograph is now attracting chal- the subject. However, the experimen- is the computational theory of mind lenging texts from other cognitive sci- (CTM), the tenet that the mind in its entists (for example, Deacon [1997]), tal psychology research that is entirety is a result of the information but Pinker himself is ahead by leaps reviewed in the book is relatively processing of the brain and nothing and bounds. This time, he has decided recent. Many of the ideas that Pinker else. CTM also encompasses the basic to tackle an even larger issue; in his presents have been in the air in evolu- latest book, How the Mind Works, tionary psychology; particularly influ- dogma of AI, computationality: Intelli- Pinker presents his hypothesis of the ential and much cited in this book are gence is a form of information pro- origins and the logical structure of the the studies of Cosmides and Tooby cessing. The book’s introduction to whole human mind. A book with (1994). Pinker’s own contribution is to these concepts borrows directly from such a title and content must, surely, boldly combine all these ideas into a AI: Pinker briefly goes through pro- duction systems and the simplest interest any AI researcher. united theory of the mind and its ori- models of neural computation (per- The book is intended for a wider gins. audience than just the professional ceptron and backpropagation). cognitive scientists’ circle. Therefore, The main contests of the CTM, of it contains many discussions that How the Mind Works, course, need to be refuted. First, appear simple and superficial for any- Pinker is an advocate of the view that one who has studied the philosophy Steven Pinker, W. W. information in our minds is represent- and foundations of AI a little deeper. Norton & Co., New ed symbolically. Therefore, he reviews However, working within AI-related some of the inherent problems of the topics, there are many of us who have York, 1997, 660 pp., purely connectionistic approaches to not followed closely the involved cog- $29.90, ISBN 0-393- intelligence. Second, Pinker discusses nitive science arguments and are not the two best-known denials of compu- aware of all the recent developments 04535-8. tationality and AI—Searle’s Chinese in psychology. For us, Pinker’s book room and Penrose’s fierce and delusive serves as a good introduction to the attacks on AI (cf., LaForte, Hayes, and big picture. The less advanced pas- Ford [1997]). Pinker, fortunately, does sages of the book should be worth tol- Reverse Engineering not dwell on any of these unfruitful erating even for a dedicated cogni- the Mind topics too long but swiftly moves on tionist because of the book’s other to build his case about the general In Pinker’s own words, the book is merits. architecture of the mind. It is not an accident that Steven about “reverse-engineering the neural The other cornerstone of Pinker’s Pinker keeps authoring popular sci- computer fitted by natural selection case is the theory of evolution. Like ence books that attain great attention with combinatorial algorithms for AI, Darwinian natural selection still and success; he is a talented writer, causal and probabilistic reasoning raises feelings and voices. Therefore, and together with his background about plants, animals, objects, and the book gives an account of natural team, he is capable of digging up fun- people. …[The mind is] driven by goal selection and adaptation. The review

Copyright © 1998, American Association for Artificial Intelligence. All rights reserved. 0738-4602-1998 / $2.00 FALL 1998 135 Book Review entails refuting backward causation, Reasons for Emotions system starts developing, and it is which, in retrospect, is what natural most vulnerable to toxins. selection might seem to do. Adapta- In the second half of the book, Pinker This explanation for pregnancy tion of an organ to perform a different is on his own ground—psychology. sickness is so natural that it almost task than its original function, howev- This is the most interesting part of the seems trivial. Nevertheless, it is only a er, has been attacked with arguments investigation into the human recent discovery, and no satisfactory of the type “half a wing is not useful.” mind—exploring ways in which natu- explanation existed before it. Morning Pinker, therefore, meticulously ex- ral selection could have opted for a sickness is a specialized emotion that plains the functioning of adaptation. humanlike intelligence and reverse- only affects pregnant women for a When discussing evolution, one can- engineering emotions. On the surface, limited time. Moreover, it is a physical not avoid the argument of what is the it seems that intelligence of human feeling, not a general emotion. Can impact of heredity (evolution pro- magnitude—and the large, uneco- general emotions such as disgust, fear, nomical brain that it requires—could duced) and learning (environment happiness, anger, and romantic love hardly have been favored over much imposed) on the human mind. Of also be traced back in the same man- simpler survival options. In particular, course, heredity and learning are not ner? The generality of these emotions, our capacity for general and abstract mutually exclusive, but Pinker’s posi- of course, makes it harder to pinpoint reasoning seems, from the evolution- tion is that little in the human mind’s a sole purpose for them, but Pinker ary point of view, to be futile. Such a kernel (and personality) is learned. For gives it a try. Disgust, naturally, works faculty must be an adaptation, adapta- example, identical-twin studies have against digesting poisons; fears pre- tion of the reasoning capabilities that clearly demonstrated that much more pare us to meet dangers; the pursuit of helped our foraging ancestors to out- than we usually think of human happiness is a (calibrated) way of striv- wit prey. What has been the impetus behavior and psyche is innate rather ing after Darwinian fitness; anger is for the unique growth of human brain than acquired by interaction with the one of the moralistic emotions—the capacities that has not happened with environment. strategies in the reciprocity game apes or other, more distant animals? The human mind was fitted for among humans—the particular func- Pinker proposes four main reasons: (1) ancestral environments, which is why tion of which is to cause desire to pun- primates are visual animals, and nego- our senses might sometimes leave us ish the cheaters among us (Trivers tiating the 3-D world requires reason- stranded in the modern world. For ing about movable objects in there; (2) 1985); and finally, romantic love is an example, visual illusions have long group living stimulates social competi- emotion that ensures the uncondi- been used as public amusement, and tion; (3) bipedal walking has left the tionality of pair bonding. they cause constant amazement. The hands free for creative tool use; (4), Pinker also tries to find the cause for human vision is probably the most hunting, besides demanding brain, some human actions—and the emo- extensively studied and the best enables it to grow by providing the tions behind them—that are most understood of the brain modules rich nutrient, meat. often written off as works of mental (mind organs). It serves as Pinker’s Most of us nurture the idea that illness or lunacy, with no real need for, main evidence for his case. About emotions come from the nature, or possibility of, a psychological expla- vision, we know that it is like Pinker inhabit the body, are somewhat irra- nation. The ghastly example consid- paints the rest of the mind to be: The tional, and are mostly uncontrollable, ered in the book is a mass murderer eyes produce the raw data for the whereas the intellect resides in the running amok. Even such horrendous- brain to chew on. Allocated in its own mind, derives from civilization, is ly extreme actions have an underlying specified regions of the brain, there is rational, and is deliberate. Pinker general psychological phenomenon. a mental module that takes care of paints another picture: Emotions are Human social life is all about relations, vision production. Image processing as engineered as anything else in our and relations are mainly about balanc- entails an enormous amount of com- mind. They constitute the mecha- ing between parallel and opposite putation. There are inherited con- nisms that determine the brain’s high- interests. False emotions and other straints that affect our interpretation est-level goals. This quite recent view bluffings are tactics in these everyday of the scenery that we are witnessing. in psychology offers us the possibility negotiations. To deter unscrupulous We compile the images into internal to reverse engineer emotions, which is attempts to take advantage of you and representations (in Marr’s [1982] ter- a more yielding approach to under- hurt you beyond tolerance, a retalia- minology, a 2-1/2–dimensional (D) standing human nature than any of tion mechanism must exist, an uncon- sketch is converted into a 3-D model). the former trends of psychology. As trollable doomsday machine—the Moreover, the vision ability is innate one example, Pinker uses morning final seal for the authenticity of the but attains its final form only through sickness of pregnant mothers, a phe- feelings and promises. Homicide learning. All these aspects of human nomenon for which only limp Freudi- streaks get an explanation through visual perception have been convinc- an or vague hormonal explanations this theory: They are results of this ingly demonstrated in psychology, were available before. Recently, this retaliation mechanism in action but neuroscience, and other disciplines. universal emotion was reverse engi- distorted and blown totally out of pro- The evolutionary development of an neered to be a protective mechanism portion. (The articulated reasons for eye has a feasible explanation. in the state when the embryo’s organ the recent schoolyard killings in

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Arkansas fit this theory scarily Taking the Geek Out of AI book to be excellent promotion for AI well—see, for example, Gegax, Adler, research and Steven Pinker to be a wel- and Pedersen [1998]). Many of the ponderings in this book come spokesman for our common Life is all about gene spreading— might seem to be out of the scope of cause. maybe not a person’s life but the life an AI researcher’s interest, humanistic on Earth in general. Such is the prereq- jabber with no relevance to building References uisite of natural selection. Therefore, intelligent machines—for example, Cosmides, L., and Tooby, J. 1994. Beyond human relations and interactions the argument of innate abilities and Intuition and Instinct Blindness: Toward should be, to a high degree, deter- free will. This book also does not an Evolutionarily Rigorous Cognitive Sci- ence. Cognition 50:41–77. mined by the expected profits and probe deeply into the foundational losses in the competition of forward- issues of the CTM, and at times, Pinker Deacon, T. W. 1997. The Symbolic Species: The Co-Evolution of Language and the Brain. ing one’s own genes. That, naturally, skates on thin ice. Why then should an AI researcher spend his/her valu- New York: Norton. pretty much boils down to sexual rela- able time with this voluminous book? Gegax, T. T.; Adler, J.; and Pedersen, D. tionships—to their desirability and If you are well acquainted with the 1998. The Boys behind the Ambush. undesirability, different benefits and theories of evolutionary psychology, Newsweek 131(14): 10–14. costs of sex for men and women, com- Pinker’s book will probably not add LaForte, G.; Hayes, P. J.; and Ford, K. M. petition over the most promising mat- much to your knowledge. Otherwise, 1997. Why Gödel’s Theorem Cannot ing partners, and so on. Of course, Refute Computationalism: A Reply to Pen- there are many good reasons for read- that is not the whole truth; there are rose. Pensacola, Fla.: University of West ing this book. The approach of reverse other aspects to life than just gene Florida, Institute for Human and Machine engineering the human mind, includ- spreading. For example, the social rela- Cognition. Unpublished manuscript. ing the emotions, can widen the scope tions and pressures affect our behavior Marr, D. 1982. Vision. New York: Freeman. of AI and make us better see the true and feelings. Pinker, S. 1994. The Language Instinct. New potential of our discipline. It is inevitable that a book entitled York: Harper Collins. Can the CTM model that is develop- How the Mind Works should close with Trivers R. 1985. Social Evolution. Reading, ing in evolutionary psychology a chapter entitled “The Meaning of Mass.: Benjamin/Cummings. answer Yeap’s (1997) recent cry for an Life”—the title of a Monty Python Yeap, W. K. 1997. “Emperor AI, Where Is AI theory of the mind—not yet, but film. The final chapter of the book Your New Mind?” AI Magazine 18(4): taking the evolutionary aspects of the 137–144. reflects on the higher values of life. human mind and intellect into What purpose do the arts, music, fic- account opens new doors for AI tion, humor and laughter, and religion research as well. How the Mind Works serve in our life, and what has been gives us an appreciation of the fact their role in the human evolution? that the human neural computer The speculative explanations for these comes fitted with many basic algo- aspects of life are not worked through rithms, which only need to be tuned Tapio Elomaa is an assistant professor in as thoroughly as those for emotions in by learning for full operation. It is too the Department of Computer Science at the the preceding chapters of the book. often that mind and intelligence are University of Helsinki, Finland. He current- ly works as a Marie Curie fellow in the Joint Pinker is not able to clarify every- searched from systems that start from thing by taking the evolutionary view- Research Centre of the European Commis- a tabula rasa configuration. sion in Ispra, Italy. His main field of point. An emotion that evades expla- Quite often, the AI curriculum has, research is machine learning. His other nation is grief. A short period of in addition to computer science, only research interests include knowledge dis- sorrow could be explained away by it philosophy and mathematics as other covery and data mining, robotics, and the being a pause that helps to adapt to reference disciplines. It is refreshing to philosophy and foundations of AI. His e- the changed situation, but what pur- get psychology and even biology as mail address is [email protected].fi. pose can excessive grief, which can other new coordinates. It takes the even lead to the death of the griever, worst geek out of the idea of AI. In serve? What is music’s function? teaching a basic course on AI, I would Many theories about music have been use this book as a source of additional, proposed, but none of them seem con- motivating material, and I would sug- vincing enough. Of course, Pinker is gest it as background reading for my not able to solve the most profound students. philosophical problems, which also Steven Pinker’s book takes you on tease AI researchers, such as subjective an enjoyable ride within topics of experience, self, free will, meaning, both professional and personal inter- knowledge, and morality. He circum- est. It forces your mind to think about vents even trying to explain these top- the mind, and the pondering does not ics by accepting the view of cognitive stop after you lay the book down; as closure—these matters are simply pointed out in the book, we all are beyond the human cognitive faculties. intuitive psychologists. I find this

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