Mike Gurven: UCSB

Personality traits (i.e. behavioral syndrome or disposition) have now been documented in a large number of species, and account for substantial behavioral variation among individuals. How heritable variation in personality is generated and maintained in populations, however, remains a puzzle to evolutionary biologists. Despite the industry of personality research in humans, relatively little tests evolutionary hypotheses and none in small-scale societies experiencing high fertility and mortality. I present personality data from Tsimane forager-horticulturalists and test whether the Big Five dispositional traits are related to fertility, health and other fitness-related outcomes. I also argue that a focus on personality differences can shed insight on small group social dynamics. Results are discussed in light of alternative notions of state-dependence, balancing and fluctuating selection.