Thursday, May 31, 2007

British brain sex

Illustrating the power of online research methods, the journal Archives of Sexual Behavior has recently published a variety of papers on sex and cognition using data gathered from over 200,000 people via the BBC website. An introductory editorial can be found here.

One of these studies, by Maylor et al., discusses four experimental tasks that have been associated with sex differences in the past (mental rotation, line angle judgment, category fluency, and object location memory) that were represented in the vast BBC dataset.

The number of participants is staggering when compared to the usual cognitive psychology study, and not surprisingly is skewed in favor of the younger age cohorts.

The results in a nutshell: the men outperformed the women on mental rotation and line angle judgment, and the women outperformed the men on fluency and object location memory. (Of course, how much of these sexual dimorphisms would be inherent to the sexes in the absence of a strongly sexually dimorphic culture is a much larger question.)

Further, when looking at the data broken down by sexual orientation, gay and bisexual men and women had average scores that were less sexually dimorphic those of the heterosexuals. For instance, gay women scored better on mental rotation than did straight women (see Figure 3A left in the paper), and gay men scored better on fluency than did straight men (Figure 3C right). This less-dimorphic pattern doesn't hold up across the board, though; Figure 3D suggests that the gay participants might be finding le mot juste more often regardless of whether they were men or women.

The data plots across all of the experiments show a large decrease in scores with increase in age, and as the title of the paper suggests, the authors make much of the different patterns of decline between the two sexes. One thing that bears mention regarding this kind of study is that this isn't a longitudinal study in which the same people are followed over time. Rather it's a cross-sectional study in which the different age groups are represented by people who are products of different eras. As an example, if you consider the education of the people participating in this study, you find that the younger participants are more educated, and further that the difference in education between men and women is bigger for the older generations. Something to keep in mind when considering arguments about different degrees of cognitive "decline" in men and women.

Nonetheless, this and the other studies represented in the special issue bode pretty well for the future of online studies. Where are my 200k participants?

Oh, I almost forgot the reason I found this article to begin with. Judy Skatsoon of the Australian Associated Press seems to think that performance on mental rotation tasks is the same as map-reading:
It has long been a tedious joke that women are bad at reading maps, but there could be some truth in it. A new study into the mental skills required to read a map has handed blokes new ammunition and dealt heterosexual women a final indignity.
Oh, for shame, Judy. Carol Lloyd of is having none of that.


Maylor, E. A., Reimers, S., Choi, J., Collaer, M. L., Peters, M., & Silverman, I. (2007). Gender and sexual orientation differences in cognition across adulthood: Age is kinder to women than to men regardless of sexual orientation. Archives of Sexual Behavior, 36, 235-249.

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