Grooming, Gossip, and the Evolution of Language

I read this book when it first came out, and very much enjoyed it. Oddly enough, I was even able to make use of what I learned from it in my job. There are three main points to the book: 1. There is an observed correlation between neocortex ratio (the ratio of the volume of the neocortex to the volume of the more primitive parts of the brain) and group size among social primates. Note that primate groups achieve cohesion partly through mutual grooming. 2. Dunbar extrapolates this correlation to the human neocortex ratio, with a resulting group size of about 150. While such extrapolation potentially yields nonsense, in this case there is significant evidence that human group size does have a breakpoint at about this number. Hunter-gatherer village sizes, the organization of armies, parish sizes, and many more examples show a natural limit of between 100 and 200 people. 3. Dunbar theorizes that the development of language was encouraged by the need for interaction among groups that were too large for mutual grooming. (Humans are not observed to groom each other the way other primates do, and a group of 150 is too large for this behavior because of the time that would be required.) In his theory verbal interaction--or, colloquially, gossiping--replaced grooming in humans. While Dunbar's theory is interesting, and may be right, even if it is wrong the book is worth reading for the first two points. It is very instructive regarding why groups work the way they do, and why large societies inevitably have bureaucracies. I read this book back in the days when Dan Golden was NASA Administrator, and pushing his "Faster, Better, Cheaper" approach to space exploration. (Which had both successes and failures.) I later had a government employee, who was planning a multi-billion dollar space program, ask me if I thought it could be managed with a "Faster, Better, Cheaper" approach, and I said no, it was too large. Although this seemed obvious, I then asked myself why that would be the case. I eventually put instinct together with Dunbar, and realized that you couldn't run a streamlined program if you couldn't keep the size of your core group to about 150 people who interacted with each other. Later reading of accounts of "Faster, Better, Cheaper" programs that succeeded, and reports from panels set up to examine failures, confirmed this conclusion. So I believe there is a message here for both small businesses and also for larger enterprises trying to decide how to structure programs. This book is thought-provoking and well worth reading.

exiting but rigorous different approach to the human evolution. It gives scientific context, opens new doors, stimulates, gives new meaning to our social habbits

This book belongs on the shelf along with "The Origins of Consciousness in the Breakdown of the Bicameral Mind", "The Moral Animal", "Non Zero", "The Third Chimpanzee" and "Darwin's Dangerous Idea". It is a brilliant theory of the origins of language, supported by statistical analysis of physiological data (relative cortex size of primates, including humans), sociological data (the size of human groups across societies ranging from hunter gatherers to modern armies) and current social psychology experiments by his grad students (spot checks of random conversations in malls and pubs). Well supported, and startling, you will look at your society and your use of language differently.

Many theories on the origin of language have been offered in recent years. They range from divine gift to something derived from hunting gestures. With no fossil evidence available, all are speculative and defensible only by logical derivation. Dunbar has offered the most likely scenario for human language. Using persuasive evolutionary roots, tied securely to observed practices of our primate cousins, he builds a coherent picture. While the foundation rests on primate grooming practices, Dunbar shows how this activity led humans developing social interactions to become language. Because we, alone among the primates, also evolved the necessary physical equipment for speech, we are the ones who produced complex languages. Dunbar's account is presented in lively style, showing his own language skills to the full. It may seem a twisted path from scratching in your neighbour's fur to the complexities of human speech, but Dunbar clearly shows us how evolution traversed it. Part of the story lies in our adapting an upright stance and bipedal locomotion. The enlarged human brain, already given a boost by primates having a proportionally larger brain than other animals, also contributed. Our needs drove us to greater mobility leaving less time for interactive grooming. The brain's demand for resources turned grooming into a waste of valuable food gathering time. Speech was the means of retaining contact and the grooming habit was lost. The most important food gathering wasn't the hunt for meat, but the gathering of vegetables. Meat supplied only a small portion of the nutritional bulk compared to the vegetables garnered by the community's females. From this reality, Dunbar proposes speech developed more rapidly in females than in males. Dunbar's analysis doesn't stop at the edge of the African forest, but probes into parties, pub conversations and business meetings. No facet of human verbal communication has been overlooked in this survey of our speech habits. One element of our social structure lies in the size of our personal "communities". Research shows that primate communities share a viable group size of about 150 individuals. Whatever your living circumstances, a careful count will show you probably interact closely with no more than that many other people. Dunbar shows that even in the urban environment, this figure holds. It isn't the number of neighbours we have, but how many people we communicate with personally. This figure derives from deep primate evolutionary conditions in which 150 was the likely group size in which we could develop effective social skills. "Gossip", in Dunbar's view is simply a synonym for social communication. We talk more about people than we do about philosophy - or anthropology.In conclusion, Dunbar views the current communication environment with some caution. He notes that the rise of electronic communication hasn't replaced the practices we developed on the African savanna. All the prom

Besides the general argument that we needed to develop language to make more friends than we could make grooming, Dunbar has some interesting observations that illustrate the breadth of his work. Here are a few:1. Monkeys developed the ability to eat unripe fruit, dooming the ancestors of apes, chimps, and humans to starvation unless we came up with a response, since we depended on ripe fruit for survival.Our ancestors' response was to move out of the central forest and into the forest fringe, which made us more vulnerable to predators. We responded to THAT in three ways: selecting for a larger size, forming larger groups, and standing up (which allows better scanning for predators and less exposure to the heat of the sun).2. There are lots of social species, but to truly form small-group alliances, a species must be able to imagine what other members are thinking--and thus whether a particular other is a reliable friend or likely foe in the intragroup competition for food, safety, ..., etc. Dunbar calls this a Theory of Mind, and says that only primates seem to display it regularly. Only a Theory of Mind allows for deception ("he thinks that I think, but actually I..."), and possible deception means that there must be a reliable way to build alliances.3. Females of many species look for an expensive commitment from prospective mates--an elaborate nest, for example, that takes a long time to build. Their implied reasoning is that even if he's tempted to stray, he won't want to go through the hassle of building another big nest. Having to groom your closest friends and allies is the same kind of commitment.4. Dunbar's grad students have done studies of overheard conversations and newspaper contents, and generally discover that approximately 2/3 of a human communication is gossip about oneself or others.5. His theory was inspired by the correlation across primate species of group size, clique size, brain size relative to body size, and neocortex size relative to brain size. According to the graphs, the natural human group size is 150 people. (His arguments attempting to prove this hypothesis are interesting, but not among his most convincing.)This is a fun book, the kind of scientific speculation that lays out a broad theory and invites others to disprove it or come up with something better...