"Brain Sex" [Featured Book]


KIRKUS Review:

Brain Sex by Anne Moir & David Jessel

"If men and women are equal, why have males been the dominant sex virtually throughout history?

   Here, geneticist Moir and BBC- TV writer-producer Jessel argue convincingly that the answer lies in the difference between the male and female brain. Writing with clarity and style, and documenting their data every step of the way, Moir and Jessel explain how the embryonic brain is shaped as either male or female at about six weeks, when the male fetus begins producing hormones that organize its brain's neural networks into a male pattern; in their absence, the brain will be female.

Not surprisingly, there are endless variations in degree of maleness, and mishaps can lead to a male brain in a female body and vice versa. Moir and Jessel include a brain sex test that lets the reader discover just how masculine or feminine his (or her) brain is. For the nonscientist, they translate considerable research into the structural and organizational differences between male and female brains, demonstrating how these differences make men more aggressive and competitive and better at skills that require spatial ability and mathematical reasoning, and women more sensitive to nuances of expression and gesture, more adept at judging character. Women, it seems, are more people-oriented than men, who are more interested in things.

Moir and Jessel assert that it is necessary to "accept who we are before arguing about what we should be,'' and that denying gender differences means ignoring their value. A literate, entertaining, and, for some, surely wrath- provoking presentation of scientific data about the differences between the sexes." -KIRKUS REVIEW



At a few hours old girls are more sensitive than boys to touch. Tests between the sexes of tactile sensitivity in the hands and fingers produce differences so striking that sometimes male and female scores do not even overlap, the most sensitive boy feeling less than the least sensitive girl. When it comes to sound, infant females are much less tolerant - one researcher believes that they may "hear" noises as being twice as loud as do males. Baby girls become irritated and anxious about noise, pain or discomfort more readily that baby boys.

Baby girls are more easily comforted by soothing words and singing. Even before they can understand language, girls seem to be better than boys at identifying the emotional content of speech. From the outset of life, girl babies show a greater interest in communicating with other people. One study involves babies of only 2-4 days old. It shows that girls spend almost twice as long maintaining eye contact with a silent adult, and girls also look longer than boys when the adult is talking. The boys' attention span was the same, whether the adult was talking or not - showing a relative bias towards what they could see, rather than what they could hear. From the cradle, baby girls like to gurgle at humans. Most boys are just as talkative, but are equally happy to jabber away at cot toys or looking at abstract geometric designs. Boys are more active and wakeful than girls - the male-wired brain of activity at work.

The female bias towards the personal shows itself in other ways. At four months, most baby girls can distinguish photographs of people they know from photographs of strangers; baby boys cannot.

On measurements of various aptitude tests, the differences between the sexes in average scores on these tests can be as much as 25 percent. A difference of as little as 5 percent has been found to have marked impact on the occupations or activities at which men or women will, on average, excel.

The area where the biggest differences have been found lies in what scientists call "spacial ability". That's being able to picture things, their shape, position, geography and proportion, accurately in the mind's eye - all skills that are crucial to the practical ability to work with three-dimensional objects or drawings. One scientist who has reviewed the extensive literature on the subject concludes, "the fact of the male's superiority in spacial ability is not in dispute". It is confirmed by literally hundreds of different scientific studies.

Boys also have the superior hand-eye co-ordination necessary for ball sports. Those same skills mean that they can more easily imagine, alter, and rotate an object in their mind's eye. Boys find it easier than girls to construct block buildings from two-dimensional blueprints, and to assess correctly how the angle of the surface level of water in a jug would change when the jug was tilted to different angles.

This male advantage in seeing patterns and abstract relationships - what could be called general strategic rather than detailed tactical thinking - perhaps explains the male dominance of chess, even in a country like the U.S.S.R, where the game is a national sport played by both sexes. An alternative explanation, more acceptable to those who would deny the biological basis of sex differences, is that women have become so conditioned to the fact of male chess playing superiority that they subconsciously assign themselves lower expectations; but this is a rather wilful rejection of scientific evidence for the sake of maintaining a prejudice.

The better spacial ability of men could certainly help to explain the male superiority in map-reading we noted earlier. Here again, the prejudice of male motorists is confirmed by experiment; girls and boys were each given city street maps and, without rotating the map, asked to describe whether they would be turning left or right at particular intersections as they mentally made their way across town and back. Boys did better. More women than men liked to turn the map round, physically to match the direction in which they are travelling when they are trying to find their way.

While the male brain gives men the edge in dealing with things and theorems, the female brain is organised to respond more sensitively to all sensory stimuli. Women do better than men on tests of verbal ability. Females are equipped to receive a wider range of sensory imformation, to connect and relate that information with greater facility, to place a primacy on personal relationships, and to communicate. Cultural influences may reinforce these strengths, but the advantages are innate.

The differences are apparent in the very first hours after birth. It has been shown that girl babies are much more interested than boys in people and faces; the boys seem just as happy with an object dangled in front of them. Girls say their first words and learn to speak in short sentences earlier than boys and are generally more fluent in their pre-school years. They read earlier, too, and do better in coping with the building blocks of language like grammar, punctuation and spelling. Boys outnumber girls 4:1 in remedial reading classes. Later, women find it easier to master foreign languages, and are more proficient in their own, with better command of grammar and spelling. They are also more fluent: stuttering and other speech defects occur almost exclusively among boys.

Girls and women hear better than men. When the sexes are compared, women show a greater sensitivity to sound. The dripping tap will get the woman out of bed before the man has even woken up. Six times as many girls as boys can sing in tune. They are also more adept in noticing small changes in volume, which goes some way to explaining womens' superior sensitivity to that "tone of voice" which their male partners are so often accused of adopting. Men and women even see some things differently. Women see better in the dark. They are more sensitive to the red end of the spectrum, seeing more red hues there than men, and have a better visual memory. Men see better than women in bright light. Intriguing results also show that men tend to be literally blinkered; they see in a narrow field - mild tunnel vision - with greater concentration on depth. They have a better sense of perspective than women. Women, however, quite literally take in the bigger picture. They have wider peripheral vision, because they have more of the receptor rods and cones in the retina, at the back of the eyeball, to receive a wider arc of visual input.

The differences extend to the other senses. Women react faster, and more acutely, to pain, although their overall resistance to long-term discomfort is greater than men's. In a sample of young adults, females showed "overwhelmingly" greater sensitivity to pressure on the skin on every part of the body. In childhood and maturity, women have a tactile sensitivity so superior to men's that in some tests there is no overlap between the scores of the two sexes; in these, the least sensitive woman is more sensitive than the most sensitive man."

As the months go by, and the child stands upright, the boys tend to show a greater interest than the girls in exploring the corners of their small world. Their greater muscle-mass helps them explore and range further than their sisters, and they make fewer journeys back to the reassuring base-camp of mother. Scientists have devised a test where a barrier is strung across the playroom, separating mother and child. The girls tended to stand at the centre of the barrier and cry; the boys made little safaris to the edge of the obstacle to see if there was a way round it.


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