Next of KinPrint
What we don't know about what chimps know
By Eugene Linden
September 1, 2010
Almost Chimpanzee: Searching for What Makes Us Human, in Rainforests, Labs, Sanctuaries, and Zoos, by Jon Cohen, Times Books, 384 pp., $27.50
Almost Chimpanzee, a play on the title of pioneering primatologist Robert Yerkes’ 1925 book, Almost Human, sets out to explore the dividing lines between humans and chimpanzees, a brave undertaking given the “chimp wars” that have raged during the past four decades over the question of the chimpanzee’s higher mental abilities. In this effort, the book’s author, Jon Cohen, a correspondent for the journal Science, almost succeeds.
The book’s virtues include an exhaustive (and sometimes exhausting) tour of all things chimp as Cohen visits labs, chimp colonies, and research stations in the United States, Europe, Japan, and Africa. He talks with geneticists, psychologists, neuroscientists, paleontologists, wildlife biologists, conservationists, animal activists, philosophers, policymakers, and legal scholars. He seems to be part Zelig, part empath, capable of relating to figures on every side of the fractious debates about the differences between chimp and human.
In one of the best passages in the book, Cohen reconstructs the forensic history of how chimps were used as surrogates in the search to understand AIDS. On a purely intellectual level, it’s a gripping story, as geneticists and other scientists try to isolate what makes us vulnerable but chimps invulnerable to HIV, only to discover later that wild chimps likely die of a simian variant of the virus to which we are immune. But nothing about chimps happens on a purely intellectual level, and one of the breakthroughs of this research was to successfully “superinfect” a chimp named Jerom at Emory University’s Yerkes Regional Primate Research Center in Atlanta so that he developed what looked like full-blown AIDS. Cohen recounts both the scientists’ story and the heartbreaking account of Rachel Weiss, a young, animal caretaker who was with Jerom as he suffered a gruesome and protracted death. While the research team was energized by this triumph, Weiss was sickened, especially when she had to help infect a healthy chimp with a transfusion of Jerom’s blood in hopes that he too would develop the disease.
This story is but one of many disturbing episodes that Cohen relates. At different times, scientists have tried to inseminate women with chimp sperm (in at least one aborted case, without the woman’s knowledge), raise chimps as humans, and, more recently, manually collect sperm from male chimps.
The narrative illustrates our schizophrenic approach to chimpanzees.
Rachel Weiss saw Jerom as a personality; the scientists treated him as a commodity, although they were never intentionally cruel. We seek out chimps’ anatomical similarities to humans, but when scientists study their cognitive abilities, they only want to know about the differences.
It’s in this area that the book comes up short, though some of the problems are the unresolved conflicts that bedevil the study of higher mental abilities. In his introduction, Cohen claims to have no agenda, but the reductionists—those who find no convincing evidence of higher mental abilities in chimps—always get the last word. To be fair, Cohen may simply be reflecting the abhorrence of members of the scientific establishment who have learned that crediting consciousness or, worse, language-like abilities to chimps, is a career killer. Sadly, scientists who study ape language can be their own worst enemies. Cohen quotes some of them to devastating effect, including one researcher who confidently asserted that a bonobo named Kanzi was eavesdropping on their conversation through a thick concrete wall.
Stories like this do not bring us any closer to what most of us want to know: Is there continuity between animal and human communication? No chimp will ever debate a Disraeli, and chimps are even more grammatically challenged than American school children, but, in the absence of a consensus definition of language, it would tell us a lot if a chimp (or another animal) could be shown to have appropriated symbols to describe novel events beyond the context in which the symbols were originally learned. Cohen throws his lot in with Herb Terrace, Noam Chomsky, and Steven Pinker, who say forget it. Others, including me, say there’s something there, but the problem in Almost Chimpanzee is that the debate is presented in such a truncated, selective, and one-sided way that the general reader will not be able to come to an independent conclusion. Regardless of the shortcomings of some of the studies of ape language in the 1960s and 1970s, the experiments spurred a renaissance in the study of animal cognition that continues today.
This combination of short shrift and selected quotation leaves the reader floundering to reconcile different parts of the book. For instance, Cohen intermittently explores whether chimps have the ability to form a “theory of mind,” a phrase coined by psychologist David Premack to refer to the awareness of the mental states of others. This would obviously be an extremely useful adaptation: if you figure out who knows what, you can more efficiently gather information or manipulate another’s mental state to your advantage. Premack dismisses this possibility for chimps as poppycock. So does Daniel Povinelli, a cognitive psychologist who has conducted experiments on the theory of mind, and who unapologetically throws his hat in with those who see no continuity between chimp and human thought. Povinelli’s view is that chimps have no concept of “ghosts, gravity, and God,” or an ability to “reinterpret” the world. Povinelli is smart and articulate, but we have no basis on which to vet these assertions against others who disagree.
But it gets worse. Earlier Cohen asserts that chimps have a form of “mindblindness,” a handicap characteristic of autism in which an individual has difficulty understanding the wants and beliefs of others. This is consistent with Povinelli and Premack, but what about the vast amount of work done describing chimp politics by Toshisada Nishida, Frans de Waal, Christophe Boesch, and others? Are all these chimp Machiavellis mindblind, unable to interpret the mental states of their peers?
Or consider a scene from the Gombe Stream Chimpanzee Reserve in Tanzania. A subordinate chimp sees a treat and suppresses his excitement because a higher-ranking male is walking by. In this seeming double-deception, the higher-ranking male continues on his way, but then hides, apparently because he smells a rat. When the junior male, thinking the coast is clear, goes for the food, the higher-ranking male reappears to snatch it. There are scores of such observations, but none make it into the pages of Almost Chimpanzee. The details of observations and experiments would help the reader to put in perspective the comments of the experts, but all too often we get only the summary judgments.
Almost Chimpanzee is nevertheless a valuable contribution to the literature on the tangled histories of chimps and humans. Cohen is comfortable delving into genetics, physiology, and other hard sciences, and does a real service by explaining some of the important genetic and physical mechanisms identified in the ongoing search to understand the differences between human and chimp. He graciously ends the book by giving the floor to Geza Teleki, an eloquent champion of chimp welfare, who puts in perspective the sad history and likely future of these apes who have the misfortune of being our closest relatives.
Eugene Linden is the author, most recently, of The Ragged Edge of the World: Encounters at the Frontier Where Modernity, Wildlands, and Indigenous Peoples Meet.
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