The Brain Knows Your Sex

Recent research by the University of Iowa shows that 'gender' may have as much to do with the person’s brain than with his or her biological sex.

Recent research by the University of Iowa shows that 'gender' may have as much to do with the person’s brain than with his or her biological sex. The study has found that one subdivision of the ventral prefrontal cortex known as the straight gyrus (SG) is proportionally larger in women, compared to men. And the size of the SG correlated with a widely-used test of social cognition, so that individuals (both male and female) who scored higher in interpersonal awareness also tended to have larger SGs. However, the study also had another test. Instead of simply dividing their subjects by biological sex, they also gave each subject a test of psychological 'gender', a questionnaire that assesses each person’s degree of masculinity versus femininity, based on their interests, abilities and personality type. And this measure of 'gender' also correlated with SG size; larger SG correlated with a more feminine personality. In other words, there seems to be a relationship between SG size and social perception, but it is not a simple male-female difference. Rather, the SG appears to reflect a person’s 'femininity' better than one’s biological sex. Women who are relatively less feminine show a smaller SG compared to women who are more feminine, and ditto for men.