Why we're hemispheres apart

Are men's and women's brains really different? A new book reignites the debate by arguing that they are

What's the difference between the male and female brain? Ah, if only we had a dollar for every one-liner that has been spawned by that little poser. An entire industry of books, films, key fobs 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 sending mobile phone text messages. "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," Brizendine 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 recent advances in neuroimaging and neuroendocrinology have provided new insights into how women and men use their brains differently. Women, she says, have 11per cent more neurones 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, this means women are more prone to hysteria than men, which will not go down well in some quarters. However, the findings fly in the face of some recent studies that claim 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 sex 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 make men cleverer: men generally are bigger 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 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," Irwing said.

But Melissa Hines, professor of psychology at City University in London and author of Brain Gender, says any test of intelligence is subjective: some favour men, others 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 goal of the research, Hines says, 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.

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," he says.

Sandra Witelson, a professor of psychiatry and neuroscience who established that Albert Einstein's brain was of average size but uniquely structured, believes that sex 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 neurones in the cortex were more densely packed. This may 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 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 neurones at the rate of 500,000 a minute. According to experience, neurones and synapses are ruthlessly pruned, a process that continues throughout adolescence. In other words, though something in the brain appears to be biological, it may 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 men have systemising brains and more women have empathising brains.

Baron-Cohen 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."

As Witelson says, it is women who bear children, so it may be that women generally don't get the same pleasure as men from focusing exclusively on their career. "It may be that the way the female brain is wired - and maybe through the evolutionary development of Homo sapiens - that there is a pleasure and a reinforcement that one gets when one is caretaking. This may be something that is more developed, on average, in women than in men."

British psychologist Jack Boyle says that "on a behavioural level, it is a matter of common sense that men and women have major similarities and also major differences. Take sexual abuse. In the thousands of cases that occur, the vast majority of abusers are male. There is overwhelming evidence that men and women behave differently." He adds that for outstanding achievement in, say, the arts and business, men also tend to go to the extremes. "You don't tend to find too many female Richard Bransons or Rupert Murdochs," he says. "Is it because they are wired differently or because of their conditioning?"

One favourite observation of comedians is that while men will use the names of roads and routes to direct someone somewhere, women will use shops. But there may be some neurological grounding for the joke. Apparently the single biggest alleged gap in brain difference is in spatial ability: men are better at mentally rotating an object, a skill related to navigation and maths. The theory is that, centuries ago, men were the hunters who wandered in search of prey and so had to use geometric cues such as distance and direction to navigate in unknown territory. Because women stayed close to home taking care of children, they had less need for such spatial skills and could rely, instead, on familiar landmarks to find their way.

Brizendine, meanwhile, hopes that her book will help to make talk of women and hormones less of a taboo subject. She has developed what she calls a female-centred strain of psychiatry focusing on the interplay between women's brain chemistry, mental health and hard-wiring, and she believes that the next generation will not assume that brain difference implies brain inferiority. "Doctors will help women to better manage the subtle pressures and emotional nuances in their lives," she says. Whether the corny jokes about men not being able to see dirt and women wanting to discuss their relationships at 2am will also die out is another matter.

Which reminds me. How many men does it take to replace a toilet roll? Answer: we don't know because it's never happened.

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Prominent Australian do-gooder becomes further unglued

The pretensions of righteousness hide a fraud and a liar



Former judge Marcus Einfeld obtained a PhD degree from a university that has been debunked in the US Congress as a "diploma mill". Pacific Western University, which awarded one of the two doctorates claimed by Mr Einfeld, was investigated by the USGovernment Accountability Office and named in Congress in 2004 for handing out doctorates for the flat fee of $US2595 ($3413). The other doctorate is from the Century University in Albuquerque, New Mexico, which is not accredited with the relevant American legal bodies. University of Sydney law dean Ron McCallum said he had never heard of the two universities, but said doctorates issued by degree mills "are not worth the paper they are written on".

Mr Einfeld, a former Federal Court judge, is facing a fraud squad investigation into evidence he gave to a Sydney magistrates court last week that allowed him to avoid a $77 speeding fine. He told the Downing Centre Local Court that at the time of the offence in January, he had lent his car to professor Teresa Brennan, who had been visiting from Florida. It later emerged that Brennan, an Australian-born academic, had died in 2003.

He will be interviewed by fraud squad detectives next week. The NSW Police State Crime Command has been called in to investigate whether he gave false evidence in the case. "Detectives attached to Strike Force Chanter have spoken with the retired judge's lawyers and now expect to interview him during the week commencing Monday, August 21," a NSW Police statement said yesterday.

In correspondence with the court, Mr Einfeld, who retired as a judge in 2001, styles himself as"The Hon Justice Marcus R.Einfeld AO QC PhD". The accountability office told US Congress that Pacific Western University sold its PhD degrees for $US2595 ($3390). It offered academic credit for "life experience" and did not require any classroom instruction, the office said. Pacific Western University, which is based in San Diego, is not accredited by the American Bar Association or the Association of American Law Schools. Century University, where Mr Einfeld says he holds a doctorate of law, is also unaccredited with the ABA or the AALS. ABA accreditation is granted to law schools only after inspections and assessments of factors including staff-student ratios, academic research and law libraries, according to the chairman of the Council of Australian Law Deans, Michael Coper.

When Mr Einfeld was invited yesterday to discuss his recent troubles, he said: "You have got to be joking. Thank you for calling. Goodbye."

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