What does the social brain hypothesis propose?

What does the social brain hypothesis propose?

• A. That primate and human brains evolved large neocortex sizes primarily to manage complex social relationships and group living.
• B. That brain size is determined by diet.
• C. That neocortex size is unrelated to social complexity.
• D. That the cerebellum governs social behavior.

Answer: (A)

The social brain hypothesis argues that the demands of living in complex social groups drove the expansion of the neocortex in primates and humans. Keeping track of relationships, reputations, alliances, and social norms requires sophisticated social cognition, so species with larger social groups tend to have larger neocortex-to-brain-size ratios. Comparative studies show a stronger link between neocortex size and typical group size than with ecological factors like diet, suggesting social complexity as a key driver of brain evolution. It doesn’t deny other influences, but it identifies social information processing as the main selective pressure. The cerebellum governs motor functions, not the primary basis for social cognitive growth, so that choice doesn’t fit.

The social brain hypothesis argues that the demands of living in complex social groups drove the expansion of the neocortex in primates and humans. Keeping track of relationships, reputations, alliances, and social norms requires sophisticated social cognition, so species with larger social groups tend to have larger neocortex-to-brain-size ratios. Comparative studies show a stronger link between neocortex size and typical group size than with ecological factors like diet, suggesting social complexity as a key driver of brain evolution. It doesn’t deny other influences, but it identifies social information processing as the main selective pressure. The cerebellum governs motor functions, not the primary basis for social cognitive growth, so that choice doesn’t fit.