Wednesday, December 21, 2011

the social brain hypothesis and its implications for social evolution

PubMed | The social brain hypothesis was proposed as an explanation for the fact that primates have unusually large brains for body size compared to all other vertebrates: Primates evolved large brains to manage their unusually complex social systems. Although this proposal has been generalized to all vertebrate taxa as an explanation for brain evolution, recent analyses suggest that the social brain hypothesis takes a very different form in other mammals and birds than it does in anthropoid primates. In primates, there is a quantitative relationship between brain size and social group size (group size is a monotonic function of brain size), presumably because the cognitive demands of sociality place a constraint on the number of individuals that can be maintained in a coherent group. In other mammals and birds, the relationship is a qualitative one: Large brains are associated with categorical differences in mating system, with species that have pairbonded mating systems having the largest brains. It seems that anthropoid primates may have generalized the bonding processes that characterize monogamous pairbonds to other non-reproductive relationships ('friendships'), thereby giving rise to the quantitative relationship between group size and brain size that we find in this taxon. This raises issues about why bonded relationships are cognitively so demanding (and, indeed, raises questions about what a bonded relationship actually is), and when and why primates undertook this change in social style.


nanakwame said...

btw - One feature of religion was teaching empathy and kindness among groupings, especially since we can't sever from the animal instinct. That role is weaker today for religious institution, plus its political role since the 1400's has been a human crime, as institutions.

Dale Asberry said...

One feature of religion was teaching empathy and kindness among groupings

Nonsense. The purpose of religion is to more clearly demarcate in-group and out-group membership. That membership criteria is then used to further exclude and eliminate the out-group.

Mirror neurons are the innate source of empathy and operates naturally (within non-psychopaths) with no need for such external social constructs.

nanakwame said...

And there is no teaching, everything is animal nature, U jest!  I love some of Christopher Hitchens and George Carlin but I can't take bitterness, which I find to be one of the worst traits in humans, especially in smart ones. Culture is so profaned in evolution that it must not be pooh poohed. Grammar Structure Before Words 

arnach said...

Is "Primates evolved large brains to manage their unusually complex social systems." belief, consensus, or fact (as asserted here)?  If the last, is that the only reason?

BTW, nice image Skylar.

CNu said...

lol, I'd classify it as a proposition - much as I would classify the social structure piece  as strictly propositional.

Neither proposition seems to wear particularly well in the context of questions raised concerning the similarities between our large-scale aggregations and those of ants