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Daniel John Povinelli Behind the ape’s appearance: escaping anthropocentrism in the study of other minds Downloaded from http://direct.mit.edu/daed/article-pdf/133/1/29/1828756/001152604772746675.pdf by guest on 25 September 2021 Look at Megan. Not just at her distinc- dedicated his life to studying these tively chimpanzee features–her accen- remarkable animals–entertain the pos- tuated brow ridge, her prognathic face, sibility that their minds are, in profound her coarse black hair–but at the totality respects, radically different from our of her being: her darting eyes, her slow, own? How can I challenge the received studied movements, the gestures she wisdom of Darwin–con½rmed by my makes as her companion, Jadine, passes own initial impressions–that the mental nearby. Can there be any doubt that be- life of a chimpanzee is best compared to hind certain obvious differences in her that of a human child? appearance resides a mind nearly identi- Actually, it’s easy: I have learned to cal to our own? Indeed, is it even possi- have more respect for them than that. ble to spend an afternoon with her and I have come to see that we distort their not come to this conclusion? Upon re- true nature by conceiving of their minds flection, you will probably acknowledge as smaller, duller, less talkative versions that her mind is not identical to ours. of our own. Casting aside these insidious “But surely it’s not qualitatively differ- assumptions has been dif½cult, but it has ent, either,” you will still insist. “I mean, allowed me to see more clearly that the it’s obvious from watching her that we human mind is not the gold standard share the same kind of mind.” against which other minds must be Faced with the overwhelming similari- judged. For me it has also illuminated ty in the spontaneous, everyday behavior the possibility of creating a science that of humans and chimpanzees, how can is less contaminated by our deeply an- someone like me–someone who has thropocentric intuitions about the na- ture of other minds. Daniel John Povinelli is Louisiana Board of Re- gents Endowed Professor of Science at the Univer- The best available estimates suggest sity of Louisiana at Lafayette, and director of the that humans and chimpanzees originat- Cognitive Evolution Group and the Center for ed from a common ancestor about ½ve Child Studies. His latest book is “Folk Physics for or six million years ago.1 This is reflected Apes: The Chimpanzee’s Theory of How the 1 Galina V. Galzko and Masatoshi Nei, “Esti- World Works” (2000). mation of Divergence Times for Major Lineages of Primate Species,” Molecular Biology and Evolu- © 2004 by the American Academy of Arts tion 20 (2003): 424–434. & Sciences Dædalus Winter 2004 29 Daniel John in estimates of our genetic similarity: we that our minds were 75 percent chim- Povinelli share, on average, about 98.6 percent of panzee? on learning our total nucleotide sequence in com- No, such coarse genetic comparisons mon. This statistic seems impressive. will hardly suf½ce to help us understand After all, such biological af½nity would the complex similarities and differences appear to be the ½nal nail in the cof½n that exist between the mental lives of of the notion that there could be any humans and chimpanzees. However, radical mental differences between in a climate where certain highly visible them and us: if chimpanzees and experts have radically anthropomor- 3 humans share 98.6 percent of their phized chimpanzees, such statistics are Downloaded from http://direct.mit.edu/daed/article-pdf/133/1/29/1828756/001152604772746675.pdf by guest on 25 September 2021 genetic material, then doesn’t it follow heralded as establishing once and for all that there ought to be an extraordinarily that chimpanzees are, at the very least, high degree of mental similarity as well? mentally equivalent to two- or three- This idea has been paraded so frequently year-old human children, and should through the introductory paragraphs of therefore be granted human rights.4 both scholarly journal articles and the A few obvious biological facts may be popular press alike that it has come to worth noting here. To begin, it was the constitute a melody of sorts; an anthem human lineage, not the chimpanzee one, that if not sung raises doubts as to one’s that underwent radical changes after our allegiance to the cause of defending the respective geneologies began to diverge chimpanzee’s dignity. from their common ancestor. Since this But what does this 98.6 percent statis- split, humans have resculpted their bod- tic really mean? It should be of immedi- ies from head to toe–quite literally, in ate interest that it is almost invariably fact; as our lineage became bipedal, misreported. We do not share 98.6 per- the pelvis, the knee, and the foot were cent of our genes in common with chim- all drastically reshaped, with modi½ca- panzees; we share 98.6 percent of our tions in the hand (including new mus- nucleotide sequence. A single nucle- cles) soon following. To top it all off, otide difference in a string of four hun- we ultimately tripled the size of our dred may code for a different allele. brain, with disproportionate increases Furthermore, as the geneticist Jonathan probably occurring in the seat of higher Marks has pointed out in lucid detail, cognitive function, the prefrontal cortex. the 98.6 percent statistic has so little Oh yes, and at some point during all of grounding in the average mind that con- this (no one knows exactly when), natu- fronts it, as to render it essentially mean- ral language–perhaps the most notice- ingless.2 We might, after all, share 50 percent of our nucleotide sequences in 3 For examples, see Sue Savage-Rumbaugh, common with bananas and broccoli. Kanzi: The Ape at the Brink of the Human Mind But what on earth does it mean to say (New York: John Wiley & Sons, 1994); Jane Goodall, Through a Window (Boston: Houghton that we are 50 percent the same as a Mifflin, 1990); Roger Fouts, Next of Kin (New vegetable? I don’t know about you, but York: William Morrow and Co., 1997). I doubt my mind is 50 percent identical to that of the garden pea. And so what 4 Steven M. Wise, Rattling the Cage: Toward Le- would it mean, exactly, if we discovered gal Rights for Animals (Cambridge, Mass.: Per- seus Books, 2000); Paola Cavalieri and Peter 2 Jonathan Marks, What It Means to Be 98% Singer, eds., The Great Ape Project: Equality Be- Chimpanzee (Berkeley: University of California yond Humanity (New York: St. Martin’s Press, Press, 2002). 1993). 30 Dædalus Winter 2004 able of human adaptations–emerged as brains–of humans and chimpanzees. Behind well. So, exactly how similar are the brains the ape’s appearance In contrast, chimpanzees have proba- of humans and chimpanzees? After all, bly changed relatively little from the if we knew that, couldn’t we directly ad- common ancestor they shared with us dress the question of their mental sim- about ½ve million years ago. Indeed, ilarity? Well, it would be a start, any- of all of the members of the great ape/ how. Unfortunately, comparisons of the human group who shared a common brains of humans and apes have tradi- ancestor about ½fteen million years ago, tionally been limited to gross considera- none, indeed, has diverged as much as tions such as size and surface features Downloaded from http://direct.mit.edu/daed/article-pdf/133/1/29/1828756/001152604772746675.pdf by guest on 25 September 2021 humans. A simple thought experiment (such as lobes and sulcus patterns). may help to put this point into perspec- Remarkably, the details of the internal tive: line up all of the species in ques- organization of human and great ape tion–gorillas, orangutans, chimpan- brain systems and structures have been zees, bonobos, humans–and one of largely ignored, in part because it’s so them immediately stands out. Guess dif½cult to study these brains, but also which one? because most neuroscientists have fre- In fact, the more we compare humans quently assumed that despite great dif- and chimpanzees, the more the differ- ferences in size, all mammalian brains ences are becoming apparent. Even ge- are organized pretty much the same. neticists are starting to catch up with Fortunately, even this is beginning the reality of these differences. New re- to change. For example, Todd Preuss, search has shown that rough similarity working at the University of Louisiana, in our nucleotide sequences obscures recently made a startling discovery the fact that the same genes may have while comparing the brains of humans dramatically different activity levels in and chimpanzees. Turning his attention the two species. So even where humans away from the frontal lobes, his previous and chimpanzees share genes in com- area of research, Preuss decided to take mon, it turns out that there are what can a look at the primary visual cortex (V1), only be described as major differences in the area of the cerebral cortex that is the gene expression–that is, whether, when, ½rst way station into the processing of and for how long genes are actually visual information. The organization of working to produce the proteins for this area of the brain has been assumed which they code.5 This is the real stuff to be nearly identical across primates. of genetic comparison, and it casts our But there, in the middle of V1, Preuss crude genetic similarity to the garden and his colleagues uncovered a distinc- pea in a wholly different light.