The field of sociobiology leaped into our consciousness with the seminal volume by that name, written by the famous naturalist and expert on ant societies, Edward O. Wilson. Wilson was pilloried by social scientists and political activists, who considered any biological perspective on human society to be a sacrilege (see the beautiful and stirring account of Wilson's travails in Ullica Segerstråle, Defenders of the Truth: The Battle for Science in the Sociobiology Debate and Beyond. Oxford University Press, 2000). Sociobiology is founded on the insight that that there are many social species, not just humans, and that the structure of social life is a major force in the tempo and pace of genetic change in social species.
In humans, social life is embodied in cultural forms that can be elaborated upon and passed from generation to generation. Thus sociobiology applied to humans leads to gene-culture coevolutionary theory, which studies the dialectical interaction between hominid genetic structure, the cultural evolution based on this genetic structure, and the effect of new levels of cultural sophistication on continued genetic evolution ---see Luigi Luca Cavalli-Sforza and Marcus W. Feldman, Cultural Transmission and Evolution ( Princeton University Press, 1981) and Robert Boyd and Peter J. Richerson, Culture and the Evolutionary Process (University of Chicago Press, 1985).
One aspect of gene-culture evolution in hominids is the continual increase in brain size and complexity from hominid origins to the present. Large brains are extremely costly to evolve and maintain. Large brain size required costly restructuring of the human birth canal and led to neoteny---birth before fetal maturation---which entails extended child-rearing and protection. Moreover, the brain requires ten times the energy of the average bodily organ, and uses about 20% of total calories consumed. What could counterbalancing advantages of large brains be?
The conventional answer to the riddle of the large brain was the capacity to use tools skillfully, and the value of communication in facilitating mutualistic cooperation. Richard Byrne and Andrew Whiten ---Machiavellian Intelligence: Social Expertise and the Evolution of Intellect in Monkeys, Apes, and Humans (Clarendon Press, 1988)--- deepened the explanation by adding that there are severely conflicts of interest among members of a social group, and a large brain will help a group member to form alliances and understand complex social forces that might well increase his biological fitness. This insight is both correct and quite valuable, but it seems to imply that large brains confer no group-level fitness benefits, but merely consist of an expensive "arms race" the hurts the species as a whole.
Robin Dunbar's contribution in this book is flows from a statistical relationship described graphically on page 63: There is a very strong correlation between neocortex ratio and mean group size in different genera of anthropoid primates (monkeys, apes and humans). Dunbar argues that there is survival value in larger groups, probably because larger groups can better defend territories and survive cataclysmic events, such as contagious disease and war. However, the complexity of group interactions increases with group size, and a large brain provides individuals with the raw materials for forging strong social ties that permit the group to overcome the purely Machiavellian tendencies described by Witten and Byrne. Language, for Dunbar, is not hypertrophied through the need to deceive, but is appropriate to the task of allowing groups of individuals to make clear subtle and conditional promises, threats, and social descriptions.
What about grooming and gossip? There is strong evidence from observation of monkey and ape behavior that grooming is a major source of group cohesion. It is carried out for many hours a day, the animals love to be groomed, and grooming solidifies cooperative alliances with great regularity. Now humans have no fur, so they cannot groom. Dunbar suggests that gossip performs the same role in humans as grooming in monkeys and apes: both are functional mechanisms for social bonding. I find it hard to take this explanation seriously---it is the sort of just-so story for which evolutionary psychology is routinely criticized (e.g., Stephen Jay Gould and Richard C. Lewontin, "The Spandrels of San Marco and the Panglossian Paradigm: A Critique of the Adaptationist Programme", Proceedings of the Royal Society of London B 205 (1979):581-598.) The costs of a large brain are extreme, and the complex adaptations required to facilitate human communication through language and gesture are intricate and costly. It is implausible that an amorphous group-level function such as "group cohesion" could not have been ensured in a far more direct manner.
However, Dunbar suggests a second mechanism, far more concrete, that was offered for the function of gossip by Magnus Enquist and Olle Leimar, "The evolution of cooperation in mobile organisms," Animal Behaviour 45:747-757, 1993. Enquist and Leimar suggest that gossip may serve to maintain social cooperation by allowing individuals to develop good reputations for their altruistic contributions to the group and bad reputations for selfish and free-riding behavior. A good reputation is personally valuable and even fitness enhancing because others will want to form alliances (including marriage) with those who consistently behave altruistically and will shun and isolate those who are selfish and opportunistic.
Of course, if the behavior of each individual were observed by all others, gossip would be unnecessary---each group member could judge for himself. But such is rarely the case. More generally, one or a few individuals will observe the behavior of a group member, and the member's reputation can be formed accurately only if his behavior is transmitted truthfully to the group. This is what truthful gossip does. If the Enquist-Leimar-Dunbar theory of gossip is correct, and I will argue below that it is, we have a very strong function for gossip, perhaps even strong enough to justify the immense costs of language acquisition.
The key point in the reputational theory of gossip is that unless gossip is almost always truthful, it will not be believed, and hence it will not be performed. But why should individuals gossip truthfully, as opposed to simply saying whatever suits the personal needs at the time (as assuredly some people do---witness the Shakespearian tragedies King Lear and Othello)? This is an important and deep question that is not yet fully answered. I believe there is a two-part answer. First, there is an evolved human predisposition to tell the truth; people will of course lie, but most will lie only when the costs of truth-telling are fairly high. Indeed, were this not the case, human language and gestural communication could not have developed: why bother communicating if people simply tell you what is in their best interest to have you believe. Truth-telling is thus a precondition of the physiology and psychology of human linguistic and gestural communication. Second, humans are very good at detecting lies, so it is difficult for a habitual prevaricator to maintain his credibility---see Leda Cosmides, "The Logic of Social Exchange: Has Natural Selection Shaped how Humans Reason? Studies with the Wason Selection Task", Cognition 31 (1989):187-276.
We thus have a tight causal loop involved with human gene-culture coevolution: hominids developed the ability to detect cheaters and the altruistic predisposition to punish anti-social behavior. This led to a vast increase in the value of linguistic and gestural communication, whence the evolution of an elaborate human communicative physiology (see my treatment in "Gene-Culture Coevolution and the Nature of Human Sociality, special issue on Human Niche Construction, Proceedings of the Royal Society B, forthcoming, available on my web site). This capacity for sophisticated and accurate information transmission led to an increased value of gossip as a mechanism of social control, and thence to a further articulation of human cooperative institutions.
The experimental evidence in favor of this view has mushroomed in recent years. First, several studies showed that humans are consummate "indirect reciprocators," willing to cooperate with others who have the reputation for honesty and altruism in collaborative affairs. For a recent overview of the evidence, see M. Milinski, D. Semmann and H.-J. Krambek, "Reputation Helps Solve the 'Tragedy of the Commons' ", Nature 415 (2002):224-226 and Karthik Panchanathan and Robert Boyd, "A Tale of Two Defectors: The Importance of Standing for Evolution of Indirect Reciprocity", Journal of Theoretical Biology 224 (2003):115-126. The role of gossip in promoting reputation-building and indirect reciprocity is demonstrated in a recent article by Ralf D. Sommerfeld, Hans-J"urgen Krambeck, Dirk Semmann and Manfred Milinski, "Gossip as an Alternative for Direct Observation in Games of Indirect Reciprocity," Proceedings of the National Academy of Sciences 104,44 (2007):17435-17440.
So, all in all, Dunbar's book is highly innovatory and basically correct, well worth reading even if the reader is up to date on gene-culture coevolution and indirect reciprocity.
Loading your book clubs
There was a problem loading your book clubs. Please try again.
Not in a club? Learn more
Join or create book clubs
Choose books together
Track your books
Bring your club to Amazon Book Clubs, start a new book club and invite your friends to join, or find a club that’s right for you for free.
Download the free Kindle app and start reading Kindle books instantly on your smartphone, tablet, or computer - no Kindle device required.
Read instantly on your browser with Kindle for Web.
Using your mobile phone camera - scan the code below and download the Kindle app.
Similar items that may deliver to you quickly
Page 1 of 1 Start overPage 1 of 1
About the author
Follow authors to get new release updates, plus improved recommendations.
Top reviews from other countries
Grazia
Brillante, ricco di spunti e appassionante.
Reviewed in Italy on August 9, 2017Freya
An interesting and thought provoking read
Reviewed in the United Kingdom on July 17, 2013