Understanding primate brain evolution.
Level 5 - mechanism / opinion, no new human data
Narrative review and comparative evolutionary path analysis without direct human clinical data.
PubMed 17301028 · doi:10.1098/rstb.2006.2001
What was done
The authors reanalyzed comparative primate brain datasets and constructed a path analysis model to evaluate the coevolution of neocortex size and social group size within a broader framework of body size, basal metabolic rate, diet, and life-history variables. They also reviewed literature examining the relationship between brain size and sociality across other mammalian taxa.
What was found
The abstract reports no specific numerical figures or effect sizes. It states that body size, basal metabolic rate, and life history constrain brain evolution and influence neocortex size and group size coevolution. Within primates, this relationship was specific to the neocortex. The path model indicated that evolving a large neocortex requires overall brain enlargement supported by dietary adjustments for energy and extended life-history timing for brain growth.
Why it matters
This work clarifies the social brain hypothesis by showing that social complexity coevolved with neocortical expansion under strict metabolic, dietary, and developmental constraints.
Limits
No sample sizes, species counts, or quantitative model metrics are reported in the abstract. The findings are based on comparative correlational modeling across species rather than experimental or direct longitudinal observations.
Cited by
- supports Across primate species, the size of the neocortex relative to the rest of the brain correlates with the social complexity and size of the social group in which the species lives.