[Paleopsych] BH: Support Found for Social Brain Theory

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Support Found for Social Brain Theory

Evidence links solving social problems to the evolution of the human brain

    By Gabe Romain
    Betterhumans Staff
    4.8.5, 4:04 PM

    The theory that solving social problems spurred the human brain to
    surpass those of other species has received a boost.

    Through tests on fossils and comparisons of our mental abilities to
    those of other animals, researchers at the [3]University of
    Missouri-Columbia have found support for a theory proposed by
    zoologist [4]Richard Alexander: That humans evolved a large brain to
    negotiate and manipulate complex social relationships.

    "We term this scenario the 'ecological dominance--social competition'
    model, and assess the feasibility of this model in light of recent
    developments in paleoanthropology, cognitive psychology, and
    neurobiology," say the researchers. "Alexander's model provides a
    far-reaching and integrative explanation for the evolution of human
    cognitive abilities that is consistent with evidence from a wide range
    of disciplines."

    Big brain theories

    Among the characteristics that differentiate humans from other species
    are our cognitive abilities. The conditions favoring the evolution of
    human cognitive adaptations, however, are mysterious.

    Hypotheses have been proposed concerning the selective advantages of
    cognitive change during human [5]evolutionary history. Explanations
    that point to ecological adaptations such as hunting and tool use have
    been proposed. Such explanations, however, haven't been satisfactory
    and none has achieved complete or general acceptance.

    "Most traditional theories, including that of Charles Darwin,
    suggested some combination of tool use and hunting were the key
    selective pressures favoring big brains, but increasing evidence of
    hunting and tool use in other species such as chimpanzees indicates
    our ancestors were not unique in that regard," says study coauthor
    [6]Mark Flinn.

    Recent models based on social problem solving linked with ecological
    conditions, say Flinn and colleagues in their study, offer scenarios
    that are more convincing.

    Social arms race

    The [7]hominid brain increased 250% in less than three million years,
    particularly in brain areas involved in cognitive development. The
    researchers credit the increasing importance of complex social
    coalitions with the human brain's evolution.

    As ecological dominance increased, adaptations that facilitated
    kinship- and reciprocity-based social partnerships arose. These
    adaptations include social, cognitive and linguistic capacities
    because such skills would have allowed people to better anticipate and
    influence social interactions with other increasingly sophisticated

    Evidence gathered supports the idea that an "autocatalytic social arms
    race" was initiated that eventually resulted in traits characteristic
    of the human species, such as concealed ovulation, extensive
    biparental care, complex sociality, and an extraordinary collection of
    cognitive abilities, say the researchers.

    "We think this model explains the data better than any other model,"
    says study coauthor [8]Carol Ward. "The tests available, although not
    comprehensive, certainly support it and provide a better explanation
    than the other ideas out there."

    The research will be published in a special issue of [9]Evolution and
    Human Behavior honoring Alexander.


    3. http://www.missouri.edu/index.cfm
    4. http://insects.ummz.lsa.umich.edu/rda.html
    5. http://www.wikipedia.org/wiki/Evolution
    6. http://www.missouri.edu/~anthmark/courses/mah/
    7. http://www.wikipedia.org/wiki/Hominid
    8. http://rcp.missouri.edu/carolward/links.html
    9. http://journals.elsevierhealth.com/periodicals/ens

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