Scientific American 
September 1996

Moral Kin?

Review by William C. McGrew

Good Natured: The Origins of Right and Wrong in Humans and Other Animals. Harvard University Press. Harvard University Press, 1996.

Morality puts individuals into conflict with the community: collective needs, set out as rules of right and wrong, constrain the options of individuals striving for their own best advantage. Yet modern Darwinian evolutionary theory is based on individual reproduction, on "selfish" genes that have been selected at the expense of others that might act for the greater good. How then could survival of the fittest lead to empathy? Despite the insights of sociobiologists, this profound paradox has led some scholars in the past to assume that the emergence of morals must be a transcendent process beyond the bounds of scientific explanation.

Frans de Waal, one of the world's best-known primatologists, has set out to prove that assumption wrong. On the final page of his startling new book, he asserts that "we seem to be reaching a point at which science can wrest morality from the hands of philosophers." How the author, a Dutch-born zoologist now at Emory University and the Yerkes Regional Primate Research Center in Atlanta, Ga., came to this conclusion makes for compelling reading.

De Waal starts by examining the apparent universality of moral systems across humanity; given that all societies have ethics, ethics must be integral to human nature. Any phenomenon that is part of human nature must be a product of both nature (evolution) and nurture (culture). Therefore, if morality has an evolutionary component, he argues, it must have its roots in prehuman species, in which the precursors of morality provided the raw material that natural selection acted on in the process of human origins. These ancestral life-forms are extinct, but closely related species are available for study.

In Good Natured, de Waal looks to other primates in particular to model the emergence of morality, to "investigate the extent to which aspects of morality are recognizable in other animals, and try to illuminate how we may have moved from societies in which things were as they were to societies with a vision of how things ought to be." He sets out not only to compare nonhuman beings with humans but also to explain how the former evolved into the latter.

De Waal likens the question of morals in other species to similar inquiries about culture, politics, language, intelligence and so on. Of course, other species do not have human morals, culture or language, any more than a cat has the same view of life as a dog. Yet animals do behave in ways that, if seen in humans, would be automatically credited as having a moral basis: they appear to express altruism, empathy, righteous indignation, retribution, community concern and tolerance.

But are the acts of other animals motivated by something resembling moral concerns, or is any such belief just a replay of romantic 19th-century anthropomorphism? De Waal argues that modern ethological methods of observation, combined with evolutionary theory focusing on the proximate causes of behavior (rather than its ultimate functions), allow us to understand much more than previous generations of animal behaviorists. By limiting the scope of inquiry, researchers can attain greater certainty about the questions they do answer.

The key to this certainty lies in explicit and precise definition of terms, so that investigators can make testable predictions instead of adding multiple layers of interpretation to everything they watch. For example, de Waal carefully defines an "expectation": "familiarity with a particular outcome to the degree that a different outcome has an unsettling effect, as reflected in confusion, surprise, or distress." The mental state is inferred on the basis of observable acts, and almost anyone who sees a primate's behavior in a particular situation will be able to tell whether its expectations were met. This ingenuity emerges again and again in de Waal's arguments, lending them crucial credibility.

So what are the basic conditions necessary for the evolution of morals? De Waal postulates two: an organism must live in groups on which it depends for subsistence and defense, and these group members must cooperate even though they also have disparate individual interests. A school of fish will satisfy the first condition, but only a few species of social mammals (among them carnivores, cetaceans and primates) meet the second one. It is from the resolution of conflicts that morality emerges.

De Waal adduces a strong body of evidence that humans and other animals share the following tendencies and capacities: sympathy as expressed in succor, special treatment of the disadvantaged, and cognitive empathy; norms exemplified in both prescriptive and proscriptive social rules; reciprocity embodied positively in the exchange of services and balanced negatively by the punishment of violators; and concern for community, which finds its expression in peacemaking and negotiation. Summed up in this way, the above suite of demonstrated qualities sounds moral indeed.

Lest the reader begin to perceive stereotyped visions of the "noble ape" from the pages of Edgar Rice Burroughs, I should point out that Good Natured is not without its limitations. De Waal himself studies only monkeys and apes confined in zoos or laboratories--animals whose existence is different in almost all respects from that of their free-living counterparts. By definition, such experimental subjects do not escape from predators, hunt for prey or search for food. Most important, they do not have the chance to be alone, whether temporarily on any given day or more enduringly over their lifetime.

Take chimpanzees, de Waal's favored species of study and humankind's nearest living relations. In nature, they are actually among the least social species of primates. At Gombe (Jane Goodall's famous site in Tanzania), Stewart Halperin found that adult males spent an average 30 percent of their waking hours alone, and mothers and their offspring spent 65 percent on their own.

Captive groups--animals living at best in large enclosures, and often in confined cages--are constantly in one another's presence. Any immigration or emigration is under the control of their human caretakers, and there are no intermediate states--the ape is either in or out. This social hothouse presents a real challenge, and the chimpanzees respond with ingenious social adaptations that are unknown in the wild. For example, adult females may form coalitions that can put even the most dominant male to flight. As de Waal notes, such behavior is unnatural, but it demonstrates the latent reserves of adaptive complexity and capacity that these apes possess.

This kind of social situation, and the moral choices that the apes make when confronted with it, probably sheds little light on the evolutionary past of either humans or chimpanzees. Our ancestors and theirs never faced such crowded conditions. Nevertheless, it can provide information that confirms and refines models drawn from behavior in the wild. De Waal is in the same position as an anthropologist trying to make deductions about Homo sapiens from observations of travelers suffering from jet lag: however relevant the condition is today, it cannot be of evolutionary significance, because our ancestors never faced rapid global travel as a selection pressure. Even so, responses to jet lag can yield insight into adaptational limits--as well as unexpected knowledge, such as a better understanding of the function of melatonin in modulating patterns of sleep and waking.

The most important implication of the book is the one with which de Waal concludes: if we must now add morality to the list of capacities shown by monkeys and apes, then questions about the morality of our own behavior toward them become even more pointed. Nonhuman moral creatures should be preserved in nature and treated better in captivity. For apes, de Waal calls for special consideration--either phase out experimentation on them altogether or at least enrich their lives and reduce their suffering. It is the moral thing to do.

WILLIAM C. MCGREW is professor of anthropology and zoology at Miami University. He has studied apes and monkeys for 25 years. His most recent book is Great Ape Societies (Cambridge University Press, 1996).