Under the Microscope: Numerous recent neuroscience studies using new imaging technology have shown differences between the male and female human brain, writes Prof William Reville.
Such results are eagerly scanned by some to see if they can explain differences in behaviour and performance between men and women. Others are convinced that any such differences between men and women are entirely caused by social conditioning. However it is extremely unlikely that biological differences play no role in behaviour. The current state of research in this area is summarised by Amanda Ripley in Time, March 7th, 2005.
Einstein was clearly much smarter than average and many people wondered if this would be reflected in his brain structure. Einstein's brain was studied after his death but it showed only very minor differences compared to the average brain. We should be cautious when correlating brain structure with behaviour.
Men's brains are slightly bigger than women's, but this does not affect IQ test results, as was once thought. There is no significant difference between men and women on IQ tests.
Different parts of the female brain are more interconnected than is characteristic of the male brain, and women involve more parts of the brain in carrying out certain tasks. Women tend to recover better from strokes than men, possibly because healthy parts of the brain compensate better for the impaired regions.
Much of the handling of emotions by the brain is done in a part called the amygdala. Men have fewer connections than women between the amygdala and higher regions of the brain that handle language and other functions. This may explain why women are more likely to talk about their emotions than men.
Studies of the developing brain show that most parts of the brain mature faster in girls than in boys, but some areas mature faster in boys. Parts of the brain that handle spatial and mechanical reasoning and visual targeting mature 4 to 8 years earlier in boys, whereas parts that handle verbal dexterity, handwriting and recognising familiar faces mature years earlier in girls.
Going on these results it would seem best to teach young boys and girls differently as otherwise you will, on average, end up with 12-year-old boys who don't like reading and 12-year-old girls who don't like science, leading on to an under-representation of women in physical and computer science and in engineering and an under-representation of men in the humanities. I will return to gender-mix in different disciplines in third-level education later.
The brain is plastic and can remould itself to a considerable extent to accommodate to the environment. When you practice a new skill, the brain changes physically to accommodate your improving level of ability. One study demonstrated an increase in grey matter at certain locations in the brains of people who learned to juggle. The grey matter disappeared when they stopped juggling. Another study showed good progress in spatial reasoning ability in young women after 10 weeks of playing Tetris for a couple of hours per week. This suggests that educational interventions at appropriate stages could effectively target sex differences in mental performance.
You collect information about your environment through your sense organs - eyes, ears, nose, mouth, and so on - and men and women also differ in how these sense organs perform. Since these organs are gateways to the brain, they affect brain development. Women can see, hear and smell things that men are blind to.
The retina of the male rat has more cells to detect motion than the female and the female has more cells to detect colour/texture. The situation in humans is almost certainly similar. This may help to explain why boys prefer playing with moving toys while girls prefer dolls with rich textures and use a wider range of colours when they draw. Both types of skill are important and were naturally selected for practical purposes. The female could warn people about poisonous plants, based on colour/texture, whereas the man would be more alert to movement in the peripheral field.
Now I will return to undergraduate gender mix in the university. I have been looking at entry figures to UCC for the 2003/2004 academic year. The general picture will be the same in the other universities. Total undergraduate entry was 2,894 and this broke into 1,146 male (M) and 1,748 females (F), ie 40 per cent M - 60 per cent F. Males and females are born in equal numbers, so why is intake of girls to university 50 per cent greater than boys? I am sure that if the intake ratio were reversed the matter would be a regular item for public debate. Is gender imbalance a problem only when females are in the minority?
When you look at faculty intake figures for 2003/2004 the picture is also interesting. In the figures that follow the first figure is gross intake and then the M/F ratio is quoted as percentages: arts 1,079, 29/71; commerce 554, 55/45; engineering 133, 83/17; food science 106, 29/71; law 147, 35/65; medicine 435, 22/78; science 440, 54/46. The most imbalanced individual degree programmes on the male side are electrical/electronic engineering (95 per cent), microelectronic engineering (100 per cent), mathematical sciences (79 per cent), physics (83 per cent). The most imbalanced programmes on the female side are early childhood studies (100 per cent); social science (90 per cent), nutrition (100 per cent), dentistry (66 per cent), general nursing (95 per cent), occupational therapy (96 per cent); speech and language therapy (100 per cent).
William Reville is associate professor of biochemistry and director of microscopy at UCC