Peeling away theories on gender and the brain

Experts used to attribute gender inequality to the “delicacy of the brain fibres” in women; then to the smaller dimensions of the female brain (the “missing five ounces”,the Victorians called it); then to the ratio of skull length to skull breadth. In 1915 the neurologist Dr Charles L. Dana wrote in this paper that because a woman’s upper spinal cord is smaller than a man’s it affects women’s “efficiency” in the evaluation of “political initiative or of judicial authority in a community’s organisation”and compromises their ability to vote.

These days gender inequality is explained by neurological differences,most popularly the notion that the surge of testosterone that occurs in the eighth week of foetal development affects the relative size of the right and left hemispheres of the brain,and of the corpus callosum,the bundle of neurons that connects the two. In the 1980s Norman Geschwind proposed the surge results in a smaller left hemisphere for males,leaving them with greater potential for right-hemisphere development which results in superior artistic,musical or mathematical talent”. In female brains the hemispheres are more collaborative,explaining women’s superior verbalising skills.

There are two problems here,Fine says. First is several studies have found no difference in hemispheric size in neonates. The supposedly larger female corpus callosum is also in dispute. Given that there may be sex differences in the brain,“what do they actually mean for differences in the mind?”

Dr Baron-Cohen builds on this theory,suggesting that low levels of testosterone result in a female,“E type” brain (for empathy); medium levels yield a balanced brain; and high levels a male,“S type” brain (for systemising). Medium levels account for the fact that some girls are systemisers and some boys are empathisers.

Dr Baron-Cohen’s lab conducted research on infants who averaged a day and a half old,before any unconscious parental gender priming. Jennifer Connellan,one of his students,who conducted the study,showed mobiles and then her face to the infants. The boys tended to look longer at mobiles,the girls at faces.

Fine dismantles the study by saying she may have “inadvertently moved the mobile more when she held it up for boys,or looked more directly,or with wider eyes,for the girls.”

She asks,“Why think what a newborn prefers to look at provides any kind of window into their future abilities and interests?”

Fine’s research is well documented. She argues that it is all in the mind. Jan Morris,the historian,travel writer and male-to-female transsexual,saw this implicit stereotyping firsthand: “The more I was treated as a woman,the more woman I became.”