Men are from Mars, Women are from Venus

Art by Matthew Jones

The idea that “Men are from Mars, Women are from Venus” is the premise of endless jokes and media articles. Most people are happy to accept that boys instinctively prefer cars and machinery while girls are attracted to prettier things. Men are comfortable with the idea that women are no good at parking and map reading, while women are equally convinced of their superior multitasking ability and emotional intelligence. Men and women are different, undoubtedly, and nobody disputes that gender specific brain circuitry exists to control our reproductive behaviours. To assume that anatomical differences between the brains of males and females also underlie differences in cognitive ability is, therefore, an easy step to make, and one that has enjoyed huge attention in the scientific literature throughout recent decades.

Some, including psychologist Dr Cordelia Fine and socio-medical scientist Professor Rebecca Jordon Young, have argued that studies to this end simply add a veneer of scientific credibility to the essentially Victorian idea that the differing accomplishments of men and women are innate and hard wired. Such a view has since been dubbed “neurosexism.” While this may appear to be a feminist exaggeration, recent work suggests that structural differences between male and female brains may not be significant enough to back up popular convictions about ‘unalterable’ differences in their capabilities. It is likely that nurture wins out over nature when it comes to personality differences between males and females; that these are cultural dichotomies rather than neural dichotomies.
What exactly are the differences between the male and female brain that have caused such controversy? Allowing for overall differences in body size, men have been shown to have bigger brains than women by about five percent. This is because the male brain contains a greater amount of white matter projecting from more numerous and densely packed neurons (nerve cells). Women on the other hand seem to have a more highly developed neuropil—the space between cell bodies that allows for communication among neurons. As a result, it has been assumed that the female brain is comparatively better at ‘interhemispheric’ or ‘long range’ communication. The female brain has also been reported to contain a proportionally larger corpus callosum—a bundle of neurons that serves as a communication link between the left and right sides of our brains, although this finding has been challenged. In 2003, Dr John S. Allen of the University of Iowa published a paper in the journal NeuroImage which stated that the differences between the sexes is in fact much lower for the corpus callosum than for other parts of the brain.

Two areas in the frontal and temporal lobes related to language have been demonstrated to be larger in women than in men, providing some biological evidence for their apparent linguistic superiority. The IPL (Inferior Parietal Lobe) is significantly larger in men than in women, particularly on the left side of the brain. This area is associated with mathematical ability, and was especially well developed in the brain of Albert Einstein. Women meanwhile possess a significantly larger OAR (Orbitofrontal to Amygdale Ratio). Put simply, this implies that women are more capable of controlling their emotional reactions. In addition, women may also have a larger limbic system, also known as the ‘emotional brain’ than men, putting them, to use a hackneyed expression, ‘more in touch with their emotions.’

Why might these differences exist? Some, for example Professor David Geary at the University of Missouri, have attributed them to evolution, invoking a standard caveman argument. Apparently a man’s superior map reading ability may be down to the fact that this was required for him to become a better hunter, while the women stayed at home working on their linguistic prowess—switching on ‘the allure’ was more of a priority as far as they were concerned. Others argue that hormones may be a more important factor. During development in the womb, hormones and other chemical substances can enter a foetus via the mother. Increased exposure to male hormones may lead to the formation of a ‘male’ brain. Support for this hypothesis, however, is varied, with foetal testosterone being linked to some, but not all, aspects of cognition and behaviour.

Gina Rippon, professor of cognitive neuroimaging at Aston University, argued last year on the BBC’s Today programme that research into neural sex differences has often been misleading, and she’s not alone in her opinion. A spate of books and articles now provide a much needed critique of the empirical evidence for the existence of hard wired differences between the brains of men and women, debunking the ‘pseudo science of neurosexism’. Professor Rippon emphasises that the similarities between male and female brains are far more overwhelming than their differences. Rippon and her team are experts in using state of the art techniques to produce illuminated cross sections of the brain, allowing them to analyse realtime responses to various environmental stimuli. By such methods, she and her team declare that they have found no significant differences between male and female cognition. Consequently, she questions the functional significance of anatomical differences between male and female brains.

Interestingly, the fact than men process language with only the left side of their brain, rather than with both sides as women do, has been found not to be the case in oriental populations— users of an ideographic or pictographic written language. Professor Sophie Scott and colleagues at the Wellcome Trust carried out research in 2003 demonstrating that this was the case in speakers of Mandarin Chinese. Both sides of the brain are used in language processing, regardless of gender. While no assumptions are made that the contrast is the result of a racial difference, it at least serves to show that isolated research projects are not universally applicable in the great gender debate.

Simon Baron Cohen, professor of developmental neuropathology at Cambridge University, is often targeted as a sexist proponent of the idea that men and women are wired up differently. He suggests that males are more likely to have an ‘S type’ or systemising type brain, while women are more likely to be great empathisers with ‘E type’ brains. His belief that “essential” differences exist between the brains of men and women has been challenged by Dr Cordeila Fine, author of Delusions of Gender, who has raised questions about his methodology. Baron Cohen’s finding that newborn boys prefer to look at pictures of mobile phones, while newborn girls prefer to look at pictures of faces may have been skewed by failings in his methodology to erase inadvertent cues given to the subjects by experimenters.

Dr Fine argues that neurological differences between men and women are not only minimal, but also changeable. This opinion is well founded—one of the defining features of the human brain is its plasticity. Our brains are likely to be more ‘soft wired’ than ‘hard wired’, and highly susceptible to cultural moulding. As a result of this plasticity, or changeable function, Fine argues that it is wrong to interpret any differences between the sexes found in brain imaging as evidence of an innate disparity. Furthermore, many studies of this kind base their conclusions on woefully small sample sizes, a common flaw in much of the empirical research.

Professor Robert Winston has agreed with the hypothesis that females who share a uterus with males (non-identical twins) may be significantly masculinised as a result of exposure to testosterone. Anybody who knows of any female with a male twin is likely to regard them as sufficiently feminine as to rubbish such an idea outright. Yet gender differences in the behaviour of small children have nevertheless been highlighted to emphasize that males and females are born differently, independent of any culturally enforced changes. However, the fact that children show these gender differences is somewhat inevitable. From the outset it is virtually impossible to raise a child in a gender neutral environment—take the use of blue and pink blankets as an example. Furthermore, discrepancies in the mechanical and spatial abilities of boys and girls can be almost completely erased by practicing mechanical tasks, supporting Fine’s views.

It seems that the idea that the brains of men and women have been constructed differently by hormones and evolution is becoming old fashioned, and the view that our plastic brains are molded more by societal forces is gaining momentum. Perhaps we’re all from the same planet after all.

Eleanor Dennis is a third year Biology undergraduate at Wadham College.

Art by Matthew Jones.