What is the evidence and what are the arguments about sex differences in IQ? You have to be courageous, naïve or stupid to talk about sex differences in intelligence or indeed sex differences in anything. Many people want to believe that men and women are equal not only in potential but also ability. They argue that even if there are small differences they should not be explored or explained because of the divisive effect that it has on both sexes. To discuss, believe in, and attempt to explain difference between different groups of human beings soon becomes ideological. It inevitably appears associated with ideas of nature-nurture which is then associated with left vs right wing politics. Over the past century there have been periods where both the “difference” and “no difference” view occurred. The growth of environmentalism and feminism from the 1960’s onwards perpetuated the idea that any observable differences between the sexes were the result of socialization. Further that they were iniquitous and could and should be changed. However the pendulum from the 1990’s onward swung the other way towards a more biological and evolutionary perspective which recognised and “explained” sex difference. There really are recognised, small but observable and replicable, sex differences at all stages at life. So in infancy we know boys are more active and spend more time awake; Girls are more physically developed and co-ordinated; Girls show R-hand preference at 5 months (not boys); Girls have better hearing and are more vocal; Girls make more eye contact and more interested in social and emotional stimuli; boys more interested in things and systems. In the pre-school period we know boys are more interested in block-building and vehicles; girls prefer doll play, artwork and domestic activities; Boys like rough and tumble play; Girls are more sensitive and sedentary; Boys show narrow interests; girls a wider range, including boy-typical activities (asymmetrical sex-typing); Gender segregation (same-sex playgroups) appears for both boys and girls. Boys groups are larger and more concerned with dominance issues; girls play in groups of 2/3 and are more sharing – concerned with fairness. There are noticeable differences particularly in language. Girls acquire language earlier than boys and remain more fluent throughout life; Girls develop larger vocabularies, use more complex linguistic constructions, enunciate and read better. Boys are less communicative and use language instrumentally (to get what they want); Brain localisation of language is more bilateral for females than males (MRI and lesion studies); Males suffer from bilingual development (e.g. memory deficit) while females seem unimpaired. If you give girls and boys at primary school different tests there are clear differences. Boys can draw bicycles better than girls who in turn are more fluent with words. Boys are better at mathematical reasoning, dart throwing and mentally finds geometric forms in complex patterns and rotating objects. Girls are better at remembering displaced objects, recalling stories, precision tasks calling for good motor co-ordination. Boys overall express more self confidence in sport and mathematics while girls do so in reading and music. Boys say any failure they experience is down to lack of effort while often girls put their own failures down to lack of ability. Girls show more concern for feelings of others and are generally better at “mind-reading”. In a study of 6 year olds listening to recorded sound of crying baby, girls expressed more sympathy but boys twice as likely to the speaker off. Boys are more affected by bereavement, separation, maternal depression, etc; but inclined to deny loss or sorrow. Boys overall express more self confidence in sport and mathematics while girls do so in reading and music. Boys say any failure they experience is down to lack of effort while often girls put their own failures down to lack of ability. Girls show more concern for feelings of others and are generally better at “mind-reading”. In a study of 6 year olds listening to recorded sound of crying baby, girls expressed more sympathy but boys twice as likely to the speaker off. Boys are more affected by bereavement, separation, maternal depression, etc; but inclined to deny loss or sorrow. But what of intelligence. Are males really brigher than females? Or is it the other way around? Does it depend on how or when you measure intelligence? It seems that at the moment there are essentially six positions that are taken on this issue 1. Intelligence cannot be accurately measured and therefore it is difficult to prove or disprove the existence of sex difference. This view emerges every so often usually perpetuated by educators, journalists or politicians who are ideologically opposed to testing. If you believe you can neither define nor measure intelligence accurately you have little to explain. Further, you can claim that all who make assertions based on actual scores or misguided and worse malicious. 2. There are no differences at all for one of two reasons. First, there are no good evolutionary or environmental theories or reasons to suppose there are sex differences Second, the early tests were so developed to show no difference. That is, subtests were included and excluded so that neither sex was advantaged or disadvantaged. So the way we measure intelligence shows no differences nor are there any. Any data to the contrary is flawed. 3. There are no mean or average differences between the sexes but there are differences at the extremes. Thus men tend to be over represented both at the extremes of the Bell Curve. The most brilliant are men and so as the most challenged meaning the average is the same but the distribution is wider for men. In any very large sample tested men are over-represented at the top and bottom. In short, the standard deviation for IQ is higher in men than in women. 4. There are numerous, demonstrable and replicable sex differences in a whole range of abilities that make up overall intelligence. The differences might not be very large but they are replicable and explicable in terms of evolutionary theory. So the biggest is for any measure of spatial ability, though ever that can be a little as a third of a standard deviation (5 IQ points). Those who take this position point to a very large number of (reputable) studies which have demonstrated sex differences in many groups and many cultures. 5. Sex differences that do emerge from studies are not real. They occur for three reasons. Females are taught humility and males hubris: and that this social message lead them to approach tests differently. So females under-perform not revealing their real ability. Next it is less of a social requirement (particularly in mate selection) for girls to be intelligence so they invest less in education and skill development, though this pattern may be changing. Third, it is all about personality facrors. Females are (overall) less emotionally stable than males and have greater test anxiety which is reflected in test performance. So any differences that emerge do not reflect underlying reality: they are about socialisation, attitudes and personality rather than actual ability. 6. There are real differences between the sexes with males having a 4-8 point advantage which become noticeable after the age of 15. Before adolescence females in fact have an advantage. The difference between the sexes is greatest for spatial intelligence. The difference is reflected in the brain size difference (corrected for body size) between men and women. Further this “real” difference “explains” male superiority in arts, business, education and science. It is this position that attracts most social commentary and criticism. There are now many more researchers than before who say that sex difference in intelligence are important and real. They tend to opt for five arguments: • Similar differences observed across time; culture and species (hence unlikely to be learned). • Specific differences are predictable on basis of evolutionary specialisation (hunter/warrior vs gatherer/nurse/educator). • Brain differences are established by prenatal sex hormones; later on, hormones affect ability profiles (e.g. spatial suppressed by oestrogen, HRT maintains verbal memory). • Sex-typed activity appears before gender-role awareness. At age 2, girls talk better; boys better at construction tasks. This is not learned. • Environmental affects (e.g. expectations, experience training) are minimal. They may exaggerate (or perhaps reduce) differences. But there is still much argument. How big (effect size) are the differences? Should one try and do something about it? What implications does this have for education? The arguments continue even as the pendulum swings between the biological and environmental interpretation. Perhaps the whole issue becomes so politically charged that it is virtually impossible to have a rational debate. This in turn means scholars avoid the research area which “too hot to handle”. Source
