March 9, 1997

A Couple of Chimps Sitting Around Talking

By NATALIE ANGIER

Like primate grooming, gossip arose to cement community ties, a new book argues

GROOMING, GOSSIP,

AND THE EVOLUTION

OF LANGUAGE

By Robin Dunbar.

230 pp. Cambridge, Mass.:

Harvard University Press. $22.95.





f something feels so good that we tend to do it to excess, you can bet there's a plausible evolutionary explanation for the strength of that desire. We love fat and sweets: fat because it is high in calories and it behooved our chronically undernourished forebears to seek fatty foods, and sweets because fruit was another ancestral staple and sweetness signals that fruit is ripe and thus digestible. We love shopping, and logically so: we're planners and hoarders, and by stocking up on available goods now, we can weather lean times tomorrow. Who would have guessed that our basic appetites would be turned against us by the invention of refrigerators, golden arches and credit cards?

Now Robin Dunbar, a professor of psychology at the University of Liverpool, offers an evolutionary explanation for another of our guilty little pleasures: gossip. No matter how lofty our intellectual aspirations, we are chatterers and snoops every one of us, greedy for stories about friends, relations, rivals, fictional characters, O. J. Simpson. As Mr. Dunbar notes at the outset of ''Grooming, Gossip, and the Evolution of Language,'' his systematic eavesdropping has shown that people devote about two-thirds of any conversation to gossip. It doesn't matter if they're in a neighborhood bar or the cafeteria of a great university, if they're men or women, clerks or corporate executives -- people preferentially talk about people. Who is doing what to whom, and do the spouses know? Is he as boring as he looks? Do you think she's getting fat? A heated exchange about politics, philosophy or the latest soccer match might occasionally intervene, but within five minutes, the author says, the discussion returns to ''the natural rhythms of social life.''

Mr. Dunbar argues that our appetite for gossip is not only natural but the source of what makes us human. Without it, he says, we might never have bothered to learn how to talk. Forget classic theories that language evolved so that hunters could coordinate a mastadon chase or gatherers describe the distribution of edible plants. By Mr. Dunbar's reckoning, language, our noblest skill, the clay of Shakespeare and Sappho, arose in the service of dish.

At the heart of this fresh and witty book is the thesis that gossip is the human version of primate grooming. Apes and monkeys spend many hours stroking one another's fur, the author explains, and they're not doing it for the sake of public hygiene. Long after a chimpanzee or gorilla has picked out every last flea and tick from a fellow's coat it will continue to pet, scratch, nibble and pinch. It will groom until the object of its attentions is practically falling over with drunken pleasure. That primates devote effort to grooming that in theory would be more productively spent foraging or mating means the practice must be essential. And so it appears that grooming is the key to primate group life. Most species of apes and monkeys live in groups, the better to defend territory, hunt, watch for predators and protect the young. Yet as any high school student knows, social life offers its own pitfalls. Snobs snub you, bullies push you around. Primates cope with the crowd by grooming. Whether to cement family ties, solicit new allies or apologize after a quarrel, they groom. Without constant mutual stroking, the primate social pact might soon dissolve.

But there's one big drawback to grooming, Mr. Dunbar says. It takes too much time. As the social lives of early hominids grew increasingly complex and their group size expanded, they could no longer afford to keep in touch, literally, with every last kin and comrade. They needed a more efficient means of socializing. Hominids already knew how to make noises; why not organize those noises into recognizable patterns? As a social device, speech offers numerous advantages over grooming. You can speak to several individuals simultaneously, and you can convey information over a wider network of individuals than other primates can. Speaking takes less time than grooming, and you can do it while engaged in another task, like gathering food. In other words, talk is cheap -- and so, perhaps, were the first things humans used it to say. The putative link between gossip and grooming helps explain why gossip feels good enough to call ''juicy.'' A chimpanzee being groomed is a creature awash in opiates, the body's natural tranquilizers. Assuming that gossip subserves the same neural structures as grooming does, it too may stimulate opiate production.

To buttress his argument that language arose for the sake of socializing, Mr. Dunbar offers comparative data between the brain size of different primates and the size of the groups in which they live. He has found a tidy trend suggesting that as the social group gets larger, so too does the volume of neocortex, the newest and so-called ''thinking'' part of the brain. The human neocortex is four times bigger than that of our closest relative, the chimpanzee. Plugging the data into his chart, Mr. Dunbar predicted that the average human group should number about 150. And that figure, he found, is meaningful on many counts. Modern hunter-gatherer tribes, which presumably reflect at least some elements of our ancestral past, live in groups of about 150. Church congregations, military companies, divisions of corporations, Hutterite villages, the number of acquaintances that the average person knows, all are close to the magic sum of 150. The size seems to fit well with the human psyche, offering both interest and intimacy.

Mr. Dunbar proposes that our forebears at some point began expanding their group size beyond chimplike dimensions to cope with changing environmental conditions and increased competitive pressures. As group size expanded, the need for a grooming substitute arose, and language proved the solution. When language arose neither the author nor anybody else can say for sure, but Mr. Dunbar suggests that the emergence of Homo sapiens, about 500,000 years ago, was marked by the appearance of language.

''Grooming, Gossip, and the Evolution of Language'' is in many ways a wonderful book, and its ideas deserve an airing. Mr. Dunbar is a clear thinker and a polymath, marshaling evidence for his thesis from such varied fields as primatology, linguistics, anthropology and genetics. On occasion, he gets sloppy. For example, at one point he refers to ''Rachel Cann, the late John Wilson and their colleagues at Stanford University in California'' when he means Rebecca Cann, the late Allan Wilson and their colleagues, then all at the University of California, Berkeley. Whether his theories are true or not -- and I remain only partly persuaded -- we may never know, for social behaviors like language do not leave fossil evidence behind. As with gossip, a measure of skepticism is in order, but that in no way spoils the pleasure of the tale.