New Italian study: Men, on average, have higher levels of perceptual reasoning and working memory

A new Italian study led by a female researcher and published by the flagship journal Intelligence reports that men, on average, have higher levels of perceptual reasoning and working memory.

Perceptual reasoning refers to mental operations used to analyze novel problems, rules, and logical relationships, and to create and test solutions. By working memory, researchers mean storing, focusing attention on, and manipulating information for a relatively short period of time.

The researchers are concerned with sex differences in subtest scores that could be due to test bias or social ways that the sexes might differ, and not due to differences in general ability (that are presumably due to biological factors).

They reasoned that if subtest scores are due to broad abilities, the size of the sex difference for the subtest should correspond to the factor loading on the broad ability. For example, if the sex difference on the arithmetic is large, the sex difference on working memory (i.e., a higher-order ability) should also be large. If the latter is small but the former is larger, the authors contend that there is bias in the arithmetic test.

While authors find evidence of some bias in the WAIS-R test, they conclude that the WAIS-IV is "quite fair." If we focus on the results from the WAIS-IV data, we find that men have a small advantage in perceptual reasoning and a moderate advantage in working memory (3 IQ points).

By contrast, there are no significant sex differences in verbal reasoning or processing speed. (Some studies have found a female advantage in processing speed). When indices are combined to created a full-scale IQ score, men have a small advantage--perhaps 1 or 2 IQ points. And, according to the authors, these differences are due to broader abilities, not various forms of bias.

UPDATE: An interesting sidenote: When analyzing WAIS-IV, the researchers look at the sex differences for 15 subtests. You might expect that if there is unintentional test bias, men would come out ahead in some tests, while women might in others. But in zero of the 15 tests do women have a statistically significant advantage.