Anatomical Gender Differences in Intelligence

             There have been many comparisons of general intelligence, between genders, assessed with standard measures that have shown no significant differences. Many argue that this does not mean that there are no differences in intelligence between males and females. Although men and women achieve similar scores on tests like the Wechsler Adult Intelligence Score (WAIS), one way of measuring the intelligence quotient (IQ), it has been shown that there are many basic and complex differences in brain structure and anatomy.  First and foremost, the average adult male brain weighs 11-12% more then the average weight of a women’s brain. This can be a very misleading statistic in several ways: 1) Men’s heads on average are 2% larger then females, 2) The female relation of brain weight to body weight larger then males, and 3) Brain size is not the best measure of intelligence. Although it has been shown that brain size in humans is strongly correlated to intelligence overall, in one particular study brain size for women was only moderately correlated to intelligence and was not significantly significant (Willerman et al, 1991). There are numerous other structural differences that are discussed in later sections, or are not directly related to intelligence. Knowing there are many differences in brain structures yet most studies confirm that there are essentially no differences between general intelligence, many people have begun research in the neuroanatomical basis of intelligence and how these differences are significant but lead to an overall equivalent in intelligence.  For example: some studies have shown that men tend to score higher in topics such as spatial and quantitative abilities, while women score higher in verbal sections.  Another difference in IQ scores is the greater variance in mends scores, meaning there are more extreme low and high scores. This simple statistic could be misinterpreted by some in thinking that on average a group of men will have more “smarter” people, but you could also say they have more who are not as smart. Other studies have gone against these findings saying that there are no differences in spatial, quantitative, and verbal abilities between genders. All in all there are many different findings on this sensitive topic, in these pages you will find some summaries of studies addressing this issue.