[July 20, Armin Raznahan] and his team published a study in Proceedings of the National Academy of Sciences that not only reported reliable sex differences in the volumes of certain parts of men’s and women’s brains but also tied those differences to the direct influence of sex chromosomes. “What we were seeking to do in this study is ask some relatively simple questions that hadn’t quite ever been directly addressed,” Raznahan says. “How reproducible are anatomical sex differences in the human brain? And what sorts of functional systems, if any, do they seem to be co-localized with?”
After analyzing this data and correcting for total brain volume (just like men’s bodies are, on average, larger than women’s bodies, so too are their brains), they discovered a number of apparent differences.
Among them was a relative size advantage for men in parts of the occipital lobe (which is associated with vision) and in the amygdala and hippocampus (regions that play important roles in emotion and memory). Women, on the other hand, had more gray matter in parts of the prefrontal cortex (which is associated with decisionmaking and self-control) and the insula (which has been connected with numerous functions, including emotion and the sense of taste). These results might seem to suggest that women have an edge over men in decisionmaking and that men have better memories, but it’s impossible to extrapolate such broad conclusions from Raznahan’s results.