The Psychology of Gender 4th Edition

Sex-Related Comparisons: Observations 117

from image rotation skills that involve shape

manipulation such as the mental rotation

task to verbal abilities. The attention dimen-

sion ranges from abilities that require a focus

of attention to abilities that require atten-

tion to a variety of stimuli simultaneously. A

study of 18- to 79-year-old adult twins who

were reared apart showed that women are

more likely to be located in the verbal diffuse

quadrant, whereas men are more likely to be

located in the image focus quadrant—although

you can see from the figure that there also is

great overlap.

Taken collectively, sex differences in

most cognitive domains have decreased

over time. It is not clear whether one sex is

improving, another sex is deteriorating, or

more recent studies are more methodolog-

ically sound. Standardized tests may be less

biased today than they were 30 years ago.

It is also possible that the political climate

has contributed to the decrease in sex dif-

ferences. The atmosphere has shifted from

emphasizing to minimizing sex differ-

ences. The political climate may be a reac-

tion to a true decline in differences, or this

Again, researchers have concluded

that sex differences in verbal ability depend

on the specific domain. Most differences are

small, but some, such as differences in writ-

ing ability, are more substantive. The sex

difference may be larger when people with

verbal difficulties are considered.

TAKE HOME POINTS

■ There is a small sex difference in verbal ability, favoring

females.

■ The size of the sex difference depends on the specific

verbal ability; the sex difference is large in the case of

writing.

■ One reason for the sex difference in verbal ability has to

do with the fact that a larger proportion of males than

females have verbal difficulties.

Comprehensive Assessment of Cognitive Abilities

Regardless of the magnitude of sex differ-

ences, one thing upon which researchers

agree is that males have more variability

in their distribution of scores on cognitive

abilities than females (see Figure 4.9). Thus

slightly more males than females are at both

the higher and lower ends of the distribution.

The explanation for this finding is not clear,

but it has implications for studies in which

select populations are evaluated, such as

talented children or children with difficulties.

One theory of general intelligence sug-

gests that there are two dimensions of intel-

ligence, one being an image-rotation versus

verbal dimension and one being a focus of

attention versus diffusion of attention dimen-

sion (Johnson & Bouchard, 2007), as shown

in Figure 4.10. The first dimension ranges

Females

Males

10 th Percentile 90 th Percentile

FIGURE 4.9 Score distributions. On many tests

of academic ability, males have more variability in

their scores than females, meaning more males are

at the high end and low end of the distribution.

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