Joel Bray

TL;DR: It is suggested that increases in absolute brain size provided the biological foundation for evolutionary increases in self-control, and implicate species differences in feeding ecology as a potential selective pressure favoring these skills.

TL;DR: The social intelligence hypothesis is tested by comparing 6 primate species characterized by different group sizes on two cognitive tasks and it is shown that a species’ typical social group size predicts performance on cognitive measures of social cognition, but not a nonsocial measure of inhibitory control.

TL;DR: Overall, there remains no clear-cut explanation for partner choice among male chimpanzees, and findings contrast with findings in other species, where stronger and more equitable bonds are typically formed by kin as well as those that are close in age and rank.

TL;DR: Chimpanzees acquired adult-like patterns on all feeding measures by infancy or juvenility and data are inconsistent with the needing-to-learn hypothesis; moreover, where delays exist, alternatives hypotheses make similar predictions but implicate physical constraints rather than learning as causal factors.

TL;DR: The results emphasize the importance of investigating social cognition across sensory domains in order to elucidate the cognitive mechanisms that underlie apparently complex social behavior and suggest that the social dynamics of haplorhine groups impose greater cognitive demands than lemur groups, despite similarities in total group size.