Reviewer #3 (Public review): Toward neuroanatomical and cognitive foundations of macaque social tolerance grades

This important work compares the size of two brain areas, the amygdala and the hippocampus, across 12 species belonging to the Macaca genus.The authors find, using a convincing methodological approach, that amygdala -but not hippocampal -volume varies with social tolerance grade, with high tolerance species showing larger amygdala than low tolerance species of macaques.Interestingly, their findings also suggest an inverted developmental effect, with intolerant species showing an increase in amygdala volume across the lifespan, compared to tolerant species exhibiting the opposite trend.Overall, this paper offers new insights into the neural basis of social and emotional processing.