What’s the difference between the male and female brain? Ah, if only we had a pound for every oneliner that has been spawned by that little poser. An entire industry of books, films, keyfobs and stand-up comedians owes its existence to the rich seam of humour that can be mined from the disparity between the sexes: Why is psychoanalysis quicker for men than for women? Because when it’s time to go back to childhood, he’s already there. Why does a man have a hole in his penis? So the air can get to his brain. What’s the main difference between women and men? Women can use sex to get what they want; men can’t because sex IS what they want. Ha, ha, ha.
But when science asks the same question, we seem to lose our sense of humour. Experts who point to biological differences in the male and female brain as a way of explaining behaviour are seen by some as shattering taboos and reinforcing stereotypes. To some, to look for differences is to look for ways to discriminate against women.
Louann Brizendine, an American neuropsychiatrist, knows that she will take some flak when her new book, The Female Brain, is published later this month. In Newsweek, she describes the book as a “kind of owner’s manual for women” and in it discusses what she believes are the biological reasons that girls gravitate to dolls and boys gravitate to trucks — and which hormones drive teenage girls to become obsessed with shopping and texting . “I know it’s not politically correct to say this but I’ve been torn for years between my politics and what science is telling us,” she says. “I believe that women actually perceive the world differently from men. If women attend to those differences they can make better decisions about how to manage their lives.”
Brizendine, who works at the Langley Porter Psychiatric Institute in San Francisco, says that recent advances in neuroimaging and neuro-endocrinology have provided new insights into how women and men use their brains differently. Women, she says, have 11 per cent more neurons in the area of the brain devoted to emotion and memory. Different levels of oestrogen, cortisol and dopamine mean that a woman becomes more stressed by emotional conflict than does a man; relatively minor worries can trigger hormones that plunge her into fear of catastrophe while this reaction can be provoked in men only by physical danger.
Put more colloquially, of course, this means women are more prone to hysteria than men, which will not go down well in some quarters.
However, the claims fly in the face of some recent studies that claim that there are negligible physical differences between men’s and women’s brains and that it is nurture not nature that is responsible for the difference in our behaviour. Janet Hyde, a leading psychologist who has examined decades of studies about gender difference, says that “there is no gender difference phenomena to explain” and books such as Brizendine’s “are bad for my blood pressure”.
No one would dispute that men and women behave in different ways; the question is why? Are we biologically wired that way or is it due to social conditioning? There is no question that men have larger brains. The male brain weighs about 1.25kg while the female’s weighs, on average, 100g less. This doesn’t neccessarily make males cleverer: men are bigger generally than women so it follows that their brains will be too. There is, though, much evidence that we use our brains differently. Women’s brains, for instance, have a thicker corpus callosum, the cable of nerves that channels communication between the brain’s two hemispheres.
Women tend to use both hemispheres for language tasks, which may be why girls learn to talk earlier than boys. The right hemisphere, meanwhile, plays a dominant role in the male brain and it is this side that we use to navigate the world and perform spatial tasks. Hence all those hilarious jokes about men being better at reading maps and parking cars.
Brizendine is by no means the first to cause controversy in this area. Two academics — Richard Lynn, emeritus professor of psychology at the University of Ulster, and Paul Irwing, senior lecturer in organisational psychology at the University of Manchester — caused a mini furore last year when they asserted that not only did men have bigger brains but they also had higher IQs — by about five points — than women. There were, they said, three men to each woman with an IQ above 130 and 5.5 men for each woman with an IQ above 145. “These different proportions of men and women with high IQ scores are clearly worth speaking of and may go some way to explaining the greater numbers of men achieving distinctions of various kinds for which a high IQ is required, such as chess grandmasters, Fields medallists for mathematics, Nobel prize-winners and the like,” said Irwing.
But Melissa Hines, professor of psychology at City University and author of Brain Gender, says that any test of intelligence is subjective: some favour men, some favour women. “It depends on what test you use. If you were using academic achievement, for instance, girls do better in school, so what does that tell us?” she says. “You cannot say that one test is more important than another.” Of Brizendine’s book she says that some of the links the author appears to make have not yet been established and that dwelling on differences for their own sake can be distracting. “What people do is read that there are sex differences in the brain — and that is accurate — and use it to indicate that all our stereotyping of males and females are biologically innate,” she says. The point is that “the brain is changeable; it changes all the time”. Experience influences our brain and it adapts. The real goal of the research, says Hines, should not be obsessing about what is different about our brains but to understand how the system works. So if you wanted to change something — say, make women better at maths — you would have more idea how to go about it.
Professor Steve Jones, a geneticist and author of Y: The Descent of Men, has said that there is absolutely no consensus about this science. “That doesn’t mean that there are no differences between the brains of the sexes, but we should take care not to exaggerate them.” Sandra Witelson, a professor of psychiatry and neuroscience, who established that Einstein’s brain was of average size but uniquely structured, believes that gender shapes the anatomy of male and female brains in separate but equal ways, beginning at birth. When she examined numerous brains she found that in the female brain the neurons in the cortex were more densely packed. This might explain, she says, why women can demonstrate the same levels of intelligence as men despite having smaller brains. “What is astonishing to me is that it is so obvious that there are sex differences in the brain and these are likely to be translated into some cognitive differences, because the brain helps us to think and feel and move and act. Yet there is a large segment of the population that wants to pretend this is not true.”
Some experts, however, believe that the physical differences in the brain may not be there at birth but are gradually sculpted. This is because social conditioning begins from the first day of life, when the brain produces neurons at the rate of half a million a minute. According to experience, neurons and synapses are ruthlessly pruned; a process that continues throughout adolescence. In other words, though something in the brain appears to be biological, it might have come to be that way because of how the body has experienced the world.
Simon Baron-Cohen, professor in the departments of psychiatry and psychology at the University of Cambridge and an expert in autism, firmly believes that the female brain is hard-wired for empathy and the male brain is predominantly hard-wired for understanding and building systems. Indeed he has advanced the theory that autism is the “extreme male brain”, not good at understanding other people but very good at systemising. He does not claim that all men have male-type brains and all women have female-type brains, just that, on average, more males have systemising brains and more women have empathising brains. He spent five years writing his book The Essential Difference because he felt it was too “politically sensitive” to complete any earlier. “I would like to believe that, deep down, men’s and women’s minds do not differ in essence. That would be a very satisfying truth,” he says. “Some people say that even looking for sex differences reveals a sexist mind that is looking for ways to perpetuate the historical inequities women have suffered. Fortunately there are now growing numbers of people, feminists included, who recognise that asking such questions need not lead to the perpetuation of sexual inequalities. In fact, the opposite can be true. It is by acquiring and using knowledge responsibly that sexism can be eliminated.”
