Crumb Trail
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Friday, September 26, 2003

Social insects point to non-genetic origins of societies

From her work studying social insects, Arizona State University biologist Jennifer Fewell believes that these remarkable animals suggest a an alternate cause behind the development of complex societies. In a viewpoint essay in the September 26 issue of the journal Science, Fewell argues that complex social structures like those seen in social insect communities can arise initially from the nature of group interactions -- the inherent dynamics of networks.


Though social networks are commonly thought of as evolutionary adaptations, Fewell turns this idea on its head by proposing that the network forms first, following the logic and pattern of group connections, then adaptation follows to strengthen the pattern. Social organization, seen in this light, is essentially an emergent property that comes from the network's geometry - a natural pattern to which organisms adapt.

Some of the more interesting ideas I've encountered regarding humans come from Herbert Gintis. This paper published by the Santa Fe Institute presents a concept of gene-culture co-evolution that has similarities to Fewell's ideas about social insects.


The internalization of norms refers to the tendency of human beings to adopt social norms from parents (vertical transmission) or socializing institutions (oblique transmission). Authority rather than contribution to fitness accounts for the adoption of internalized norms. Suppose there is one genetic locus that controls whether or not an individual is capable of internalizing norms. We extend classical models (Cavalli-Sforza and Feldman 1981, Boyd and Richerson 1985) to show that if adopting a norm is fitness enhancing, fixation of the allele for internalization is locally stable, and with a small amount of oblique transmission, fixation is globally stable. We use this framework to model Herbert Simon’s (1990) explanation of altruism. Simon suggested that altruistic norms could ‘hitchhike’ on the general tendency of the internalization of norms to be fitness-enhancing. We show that the altruistic phenotype evolves if and only if there is a sufficient level of oblique transmission of internalizable norms. This result holds even when there is a strong horizontal transmission process biased against the altruistic norm. We then use a geneculture coevolutionary group selection argument to explain why internalized traits are likely to be pro- as opposed to anti-social.

posted by back40 | 9/26/2003 01:47:00 PM


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