On average, men and women differ psychologically in small but reliable ways, such as in personality, interests, and cognitive performance, but the basis of these differences is up for debate. Are they innate or due to how we’re socialised? Neuroscientists look for traction on this question by studying sex differences in the brain.
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The University of Wisconsin-Madison team led by Douglas Dean III recruited 149 expectant mothers who brought in their infants – 77 girls and 72 boys – for brain scanning one month after giving birth.
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[T]he boys’ brains were 8.3 per cent bigger, in line with the sex difference in brain volume found in adults and the few other available infant studies. Also as seen in adults, male brains had relatively more white matter (connecting tissue) and female brains more grey matter, relative to total brain size. A number of specific neural areas were larger in males, also relative to total brain volume, such as parts of the limbic system involved in emotions.…
There were a lot of brain areas that differed structurally between the sexes, but it would be irresponsible to draw any firm conclusions about what they might mean for function and behaviour.
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The reason the new research is helpful is because it informs the interpretation of more focused studies that uncover psychological differences between the sexes.
Read full, original post: Sex differences in human brain structure are already apparent at one month of age
