Funnily enough, there is dissent even about the basic proposition that rightward asymmetry exists in the physical structure of the male brain. When the results of this particular study were scrutinised by Mark Liberman, he found that not only was the sample studied extremely small, there was also a great overlap between the men and the women.98 Other studies, what’s more, have found different patterns. While some studies of the human brain have found that ‘cerebral volume for males was larger on the right than on the left’,99 others have found that ‘leftward asymmetry was more pronounced’ in males,100 or that ‘males exhibited a leftward and females a rightward asymmetry for grey matter and females exhibited greater rightward asymmetry than males for total matter’,101 or that ‘In human male foetuses a larger right hemisphere volume has been identified, but so far no equivalent pattern has been reported in adults.’102
This is one example of the current gap between what is seen as a consensus about men’s and women’s brains, and the range of evidence that actually exists. Although so many differences between the male and female brain have been found in recent research, many of these findings have come under intense questioning, either for their reliability or for their significance. The reality is that there is no proof that femininity is laid down for women in the structure of their brains. Another example of the gap between a purported consensus and the range of evidence which I found very intriguing is the debate about the size of the corpus callosum, which is the area of the brain that contains millions of nerve fibres connecting the two hemispheres. The fashionable idea is that this area is bigger in women than in men. This idea first gained prominence in 1982, when an article was published in Science which claimed to be the first report of a reliable sex difference in the arrangement of the human brain, noting that the splenium of the corpus callosum was larger and more bulbous in women’s brains.103
Since then, it has been constantly repeated that this larger corpus callosum is linked to women’s greater empathy, or intuition, or ability to multi-task. One American journalist wrote in 2005: ‘Women’s brains have a larger corpus callosum – the connective tissue between the right and left sides of the brain – whose job it is to transfer data back and forth. Consequently, women integrate incoming data faster than men do. Women’s intuitive “sixth sense” about when the baby in the nursery is going to start squawking, or the boss is about to blow a gasket, or what someone else’s response will be before it’s stated probably has its origins not in the netherworld, but right there in the highly active corpus callosum of the female brain.’104 This journalist was along the same lines as the scientific writers who lean towards biological determinism. As Susan Pinker puts it: ‘Previous studies had shown that women have a thicker corpus callosum, the bundle of nerves that connects the two hemispheres … Scientists infer that this allows women to process emotions with dispatch.’105, 106 This theme has also filtered into self-help books in a highly exaggerated way, as we see in John Gray’s Why Mars and Venus Collide: ‘A woman’s brain has a larger corpus callosum, the bundle of nerves that connects the right and left hemispheres of the brain. This link, which produces cross-talk between the hemispheres, is 25 per cent smaller in men.’107, 108
Yet there is no solid evidence for these sweeping claims. That first article in 1982 which found that the corpus callosum is larger in women was followed by many more studies, some of which backed it up, and some of which found the opposite. In 1997 two scientists conducted a thorough review of the forty-nine studies of the subject that were published between 1982 and 1994. These scientists, Katherine Bishop and Douglas Wahlsten, had already noted the poor methodology and shaky conclusions of the famous 1982 study, noting that this article did not meet ‘conventional scientific standards’ for demonstrating a sex difference in the size of the splenium of the corpus callosum. They were concerned to see that it had been so uncritically taken up and promoted by the popular press as the source of supposed sex differences in cognition. It was because of the stark contrast, as they saw it, between opinion among popular writers and opinion among most neuroscientists, that they undertook their review, and their results were conclusive. ‘Our review of a substantial literature on the human corpus callosum does not support any sex-related difference in the size or shape of the splenium, whether or not adjustments are made for whole brain or cortex size.’109
The gulf between the evidence that is available and the way the story has been generally told clearly yawns widely here, but the corpus callosum is hardly the only area in which one can see this gulf. The popular view of the differences between men’s and women’s brains is that women’s brains are not only more symmetrical in structure, but that they also work in a more balanced way than men’s brains when processing certain tasks, particularly those to do with language.110 This is then tied into the stereotype of feminine superiority in language skills. Some research by neuroscientists has backed up this point of view; for instance, in 2000, men and women were asked to lie down in a room and listen to a John Grisham story being read. The men showed more activity on their left side, the women showed activity spread across their brains.111 The BBC chose to put it in this way: ‘Why men don’t listen: there may be a ring of truth in the female complaint that men never seem to listen to a word they say.’112 The Daily Mail stated: ‘It’s the news Sybil Fawlty knew all along. New research suggests men really do listen with only half their brains. In a study of men and women, brain scans showed that, when listening, men mostly used the left sides of their brains, the region long associated with understanding language. Women in the study, however, used both sides.’113
This particular study tested ten men and ten women. Its conclusions have not been replicated in many other tests of such tasks. In 2004 when four neuroscientists carried out a metaanalysis of fourteen studies providing data on 377 men and 442 women, no significant difference showed up in language lateralisation between men and women. In other words, men and women showed a similar balance of brain activity when doing tasks related to language such as listening or talking.114 I have not been able to find any report in any mainstream media of this analysis, compared to the widespread report of the one study that seemed to suggest the opposite.
The preference for research on the brain that seems to back up traditional sex differences over research that does not is not only seen in the media; some scientists have suggested that it occurs earlier on in the research food-chain, in the very decisions about which studies actually get published. Some have pointed out that, while a vast number of studies of brain activation are currently being carried out, those that show sex differences are much more likely to be published than those which fail to prove sex differences. This is the file-drawer problem; that the studies we have on record are a small proportion of the studies carried out, most of which show no publicity-friendly gender differences and are therefore languishing in academics’ file drawers.115
What’s more, although differences in activation and structure in women’s brains and men’s brains can be picked up in certain studies, and some of these studies may prove to be significant in the long run, there is nothing to prove as yet that these must be put down to innate differences rather than differently learned behaviours. When these differences are reported in the media or by writers who rely on biological explanations for sex differences, the assumption is often made that if you can see a difference in the brain, this suggests the difference is innate and unchangeable, that it is ‘hardwired’. Yet as we grow and change, our brains change with us. What we learn doesn’t take place in an ethereal, immortal soul with no physical being, it takes place in the connections of our living brain.116
If you want to see the way that experience can even change the size of the anatomical structures of the human brain, take a look at one clever study that compared London cab drivers to other men. For once, it wasn’t the sexes under a spotlight, but men who had chosen different paths through life. As all Londoners know, taxi drivers in London are required to learn
The Knowledge, a thorough mental map of the city. The cab drivers in this test had spent an average of two years doing The Knowledge, and so had spent significant time building up their spatial memory. And when the structures of their brains were compared to those of a control group, it was seen that part of the brain, the posterior hippocampus, was larger among the cab drivers than among the other men. The researchers therefore concluded that the posterior hippocampus was the area of the brain they relied on to store this encyclopaedic spatial understanding of London’s streets. Those who support theories of biological determinism might have jumped in to argue that it was the greater size of this part of the brain that had decided the men in favour of this career, but the researchers also found that the longer these men had been cab drivers, the bigger the posterior hippocampus, so that as they went on adding detail to their knowledge of the city, their grey matter grew. Since the volume of grey matter in this part of the brain correlated with the amount of time spent as a taxi driver, this suggested that the human brain can change physically in response to its environment, even during adulthood.117, 118
So if neuroscientists look at the brains of men and of women and see differences between them, we shouldn’t assume that these are present at birth and will be there till death. As the neuroscientist Melissa Hines says, ‘Sex differences in brain structure cannot be assumed to imply innate or immutable processes.’119 The complicated story of how the brain we are born with develops in response to our life’s experiences cannot be summed up by a narrative that seeks to reduce it to a rigid stereotype laid down at birth.
The narrative of biological determinism does not, of course, just rest on describing the differences between men and women. It speculates that these differences were laid down in our genes because it was evolutionarily advantageous for men and women to have specialised in different skills, aeons ago, way back in the prehistory of humanity. This prehistoric scenario has been described by many writers, from anthropologists to self-help gurus. For instance, the anthropologist Sherwood Washburn argued, in the seminal book Man the Hunter in 1968, that it was man’s specific role as the hunter of big game and the ‘sexual division of labour’ this entailed that lay behind the evolution of modern humans.120 To this day, a similar view of our past is used to prop up the argument that traditional gender differences are hardwired into our genetic heritage. So, to take a popular example, Allan and Barbara Pease, in their book Why Men Don’t Listen and Women Can’t Read Maps, talk about this ancestral paradise: ‘Once upon a time, a long, long time ago, men and women lived happily together and worked in harmony. The man would venture out each day into a hostile and dangerous world to risk his life as a hunter to bring food back to his woman and their children, and he would defend them against savage animals or enemies. He developed long-distance navigational skills so he could locate food and bring it home, and excellent marksmanship skills so that he could hit a moving target. … The woman’s role was equally clear … Being appointed the child-bearer directed the way she would evolve and how her skills would become specialised to meet that role. She needed to be able to monitor her immediate surroundings for signs of danger and have a highly tuned ability to sense small changes in the behaviour and appearance of children and adults.’121
Many of the writers I have quoted who support biological explanations for sex differences tend to return to a similar vision of our ancestral past in order to back up their view of why it is that men and women are so different in cognition and behaviour. This theory that men and women specialised for such different traits makes sense if our evolutionary past was one in which men and women were placed in such different situations and never needed to cross into the other’s world. We could indeed have evolved in this Stepford Wives scenario. But over the last few decades anthropologists have provided an alternative narrative of what our evolutionary past might have looked like, and suggested that it would not necessarily have been one in which men and women occupied such utterly different niches. This narrative has reassessed the evidence from modern hunter-gatherer societies and the archaeological evidence of previous societies, and questioned whether the females were solely carers who were so reliant on the achievements of the male hunters for food and protection. The consensus has arisen that the hunting of big game was not the most significant source of protein for such societies, which were more reliant on the work of the female foragers than previously supposed. Some anthropologists have suggested that it was the work of grandmothers as foragers rather than fathers as hunters which could be vital to the survival of the children in these societies.122 Others have suggested that rather than relying on the aggressive, clever men, in some hunter-gatherer societies women kill much of the hunted game, carrying their babies in slings or leaving them with other women.123 Others have suggested that fathers in such societies did more caring than was popularly supposed, without any loss of status.124 These writers have broken through what one writer has called the ‘Paleolithic glass ceiling’125 by suggesting that the gulf between man the provider and woman the carer in the societies in which humans evolved may never have been quite as rigid as some modern writers would like to think. We might have evolved in societies in which, rather than gentle, chatty women in the cave being dependent on solitary, aggressive men in the bush, everyone – male and female – had to be able to cooperate with others in their community and everyone – male and female – had to be able to meet the need to work hard and bravely to find food.
I like reading these descriptions of traditional societies and of our possible evolutionary past as much as the next person. But whether we are reading of sexist societies that seem to be the direct precursor of modern Saudi Arabia, in which the aggressive leader keeps his women in the cave to gossip and get bored and wait for his return, or of societies which sound more like modern Sweden, in which men and women go out hunting for rabbits and come back to share the childcare with each other and with the grandparents, we will never be given a kind of telescope back into the past through which we can gaze at the precise scenario that shaped our own genetic heritage. When you read those writers who seem to think that our responses to the contemporary world were decided for all of us millions of years ago, a creeping fatalism often takes over which makes it impossible for us even to imagine the possibility of creating further social change. In this fatalistic world view, the desires we have to create a better and more equal society will founder.
But surely those writers are most compelling who argue that the reason humans have managed to spread over the entire planet in so many different physical and social environments is that we adapted to be adaptable. As the eminent anthropologist Barbara Smuts said in Natalie Angier’s book Woman: An Intimate Geography: ‘Flexibility itself is the adaptation.’126 This is not to say that we are blank slates; the dynamic between biology and culture must be a mutual dynamic. But it can also be a very variable dynamic – while there are different things that each individual brings to the table in terms of innate talents, desires and visions, there are also ways in which changing situations create changing responses. Rather than getting hung up on what might have happened in the Pleistocene era, we can still discuss whether we feel there is a better society that we can work towards today.
This is not as simple as saying there is a nature–nurture divide in this debate, and that we have to choose one side or the other. The nature–nurture divide is a false one, since the experiences we have in our lives will change the physical structures of our brains or our production of hormones. There is no unchanging biological reality, free from history, just as there is no blank slate on which the finger of experience writes. Our genetic inheritance helps to determine how we filter and respond to experience, and our experience modifies how our genetic inheritance expresses itself. If we have the will and the desire to create social change, we should not be held back by the false belief that such change will necessarily founder on the rock of innate differences. There is a way beyond this fatalism.
9:
Stereotypes
I remember, when I first started thinking about some of these issues, idly asking a friend of mine who has three children, two girls and a boy, ‘Do you think boys and girls are innately different?’ At the time I dismissed her answer: ‘I think boys and boys are different, and so are girls and girls.’ But the more time I have spent with this subject, the more I have seen how vital is this apparently obvious point. The constant threat posed by the promotion of biological determinism is that it blinds us to the true variability among women and men. Instead of the unpredictable men and women we meet every day, who might be aggressive or nurturing, who might be solitary or gregarious, we are being asked to believe that all men and all women should fit templates modelled more on a pink doll or a blue robot than a real man or a real woman.
Living Dolls: The Return of Sexism Page 20
