The unfortunate thing about studies on the differences between male and female brains is that they get overstated in ways that perpetuate stereotypes. (“Women are better at nurturing, so why don’t you bring the cupcakes?”)
The unfortunate thing about stereotypes is that there’s sometimes a grain of truth at their center that gets distorted to the point of nonsense. The myth is that women are, overall, more “verbal” than men are. The truth is that both genders utter about 16,000 words per day, but grown women do seem to talk more than men do in certain contexts. In childhood, girls tend to speak earlier and with more complexity than boys do, and boys born with high levels of testosterone in their blood are more likely to have speech delays.
That’s left scientists hunting for the reasons why: Is it socialization, or differences in a so-called “language protein” in the brain, or in how the body processes testosterone?
A brain-imaging study out today from the European College of Neuropsychopharmacology supports the theory that it might be testosterone that explains how men and women, on average, handle speech and social interactions differently.
Some past studies have shown that testosterone dampens talkativeness. But researchers have been limited by the fact that they couldn’t administer extra testosterone to otherwise-healthy people. A group of female-to-male transgender people, meanwhile, offered a unique opportunity to study the effects of testosterone on the brain, since these individuals were voluntarily taking high doses of testosterone in order to assume more masculine traits.
For this study, researchers took brain scans of 18 subjects before and after their testosterone treatments. After the treatment, the levels of gray matter in Broca’s and Wernicke’s areas, two brain regions that process language, decreased, while the white matter connecting the two regions increased. One of the study authors, Andreas Hahn of the Medical University of Vienna, speculated that the reduction in the gray matter outweighed the strengthening of the connections.
“These findings may suggest that the genuine difference between the brains of women and men is substantially attributable to the effects of circulating sex hormones,” Rupert Lanzenberger, also from Vienna, said in a statement.
Individual men and women vary widely in their natural levels of testosterone. Still, to the extent that we do see language differences between men and women, this study suggests testosterone might be at play.