Marais (1969) was one of first to make a close study of the behaviour of nonhuman primates in the wild. His analyses were far ahead of their time, because he attempted to understand the actions of these creatures in terms of the evolutionary continuity with Homo sapiens that Charles Darwin had earlier proposed. Although genetic analyses were still a long way off, it was obvious to Darwin and his converts in the 19th century that the great apes – chimpanzees, gorillas and orangutans must be our distant cousins. Marais was on the right track when he observed free-living and captive baboons in his native South Africa and puzzled over the similarities – and differences – he could see between their behaviour and that of human children and adults.
Most of the questions with which Marais grappled remain unanswered. But in recent years attempts to understand primate minds have spawned a controversial new ethic. It is based on the notion that the differences in psychology between people and other great apes are too small to justify different treatment. That is, nonhuman apes should get the same ethical consideration that their human brethren receive. This view is most manifest in the Great Ape Project, which describes itself as working to raise the legal and moral status of these animals. The ultimate aim of this group is to have the United Nations adopt a declaration on the rights of nonhuman apes, one that would make all medical research on them impossible.
Supporters of the Great Ape Project are impressed by the genetic similarity between people and nonhuman apes and by the relatively short period of time since we and our closest relatives (chimpanzees) diverged from a common ancestor. Most advocates of this project point to what they consider the key psychological similarity between nonhuman apes and ourselves: Nonhuman apes, they argue, are self-aware. As a consequence of this self-awareness,...