Cognitive differences between sexes
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Differences in male and female cognitive abilities are widely established in the current scientific literature. What is still unclear is how much of these differences is due to biological and genetic differences between sexes, and how much is due to environment and culture.
These studies can lead to controversies very easily, mostly because of the following reasons:
- Scientific claims about sex differences in mental abilities are misunderstood as sexism. In truth, scientists do not say that one sex is more intelligent, hence superior, or more stupid, hence inferior, than the other. The studies focus on how, and how much, males and females think differently, and why it is so.
- Statistical results are misunderstood as general claims about men and women. If on average a sex performs better/worse in some cognitive task, this does not mean that all the people of such sex are better/worse in that task. Indeed, studies are consistent with many exceptions, and the distributions of men's and women's cognitive abilities overlap a lot. So nothing can be said on the intelligence of a single person just by knowing their sex, but statistics can be used to understand general trends on the whole population of men and women.
- This topic attracts a lot of pseudoscience, anecdotal evidence, myths, and — in the worst case — dishonest people who try to bend the science in order to support their ideas on men and women.
Male and female brains are very different. Scientists have found about 100 gender differences in the brain, regarding processing, chemistry, structure, and activity. The most notable of these differences are the following:
- On average, men have larger brain volume and brain weight compared to women, which is only partly accounted for by larger body dimensions in men.
- Men have a higher percentage of white matter whereas women have a higher percentage of gray matter.
- Women have significantly better connected neural networks compared to men's neural networks. Also, male brains are optimized for intrahemispheric communication, while female brains for interhemispheric communication.
It is widely established in scientific literature that, statistically speaking, men and women perform differently in some cognitive tasks. Men show higher spatial intelligence, performing better in tests regarding spatial visualization, spatial perception and mental rotation; while women have higher performance in verbal abilities, including speech, writing, and reading.
It can be argued that these differences in mental abilities are not biological but are the result of culture. That is, society pushes and trains males in spatial reasoning and females in verbal thinking. In this regard, studies with young children are very important, because young children have null or very low cultural conditioning/training.
A 2003 study on a sample of 1,279 children and adolescents, 637 males and 642 females, ranging in age between 5 and 19 years, found that females perform higher on certain verbal tasks and males perform higher on certain spatial tasks. This result is consistent with previous studies regarding male/female mental abilities.
A 2006 study on a sample of 38 male and female children, 3, 4, and 5 years old, showed that males performed better than females in a spatial task involving the search of a hidden object, and that the male scores increased with age, while the female scores did not. A previous 1999 study on a sample of 288 male and female children, 4 to 7 years old, found a significant male advantage in tests involving mazes and spatial rotations of shapes.
Statistical data shows that there is no significative difference between the average IQ scores of men and women. However, the variance of male scores is higher than that of females, hence more males than females are in the top and bottom of the IQ distribution.
Mental health disorders
Although men and women may suffer the same mental health disorders, some illnesses are more common in men than women, and vice versa.
- Anorexia is about eight times more common in females.
- Antisocial personality and substance use disorders are more prevalent in men.
- Anxiety and mood disorders are more frequent in women.
- Attention deficit hyperactivity disorder (ADHD) occurs three times more often in males. An evolutionary explanation could be that some women are more attracted to males displaying hyperactivity and impulsivity, increasing the frequency of genes that predispose males to ADHD.
- Dyslexia is up to three times more prevalent in males. This seems to be related to the different gray matter/white matter ratios in men's and women's brains.
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