The Psychology of Gender 4th Edition

Sex-Related Comparisons: Observations 109

were compared. Thus, sex differences in spa-

tial abilities do not appear to be disappearing

with time (Halpern & Collaer, 2005).

The meta-analysis showed that the

size of the sex difference increased with age

(Voyer et al., 1995). Averaging across spatial

abilities, sex differences ranged from zero to

small in children under 13 but ranged from

small to large in children over 18. Research

seems to suggest that the sex difference in

visual-spatial skills emerges around kinder-

garten or first grade (Halpern et al., 2007).

However, one study showed that sex dif-

ferences in mental rotation may already be

apparent among 3- to 4-month-old infants

(Quinn & Liben, 2008).

Of the three spatial abilities discussed,

the sex difference in mental rotation is larg-

est and stable over time, causing it to receive

the most research attention. Investigators have

wondered whether part of this sex difference is

due to women and men using different strate-

gies to manipulate objects. There is some evi-

dence from fMRI studies that men use a more

holistic strategy by rotating the whole object

at one time, whereas women use a more ana-

lytic strategy that involves comparing specific

features of the object (Jordan et al., 2002). The

latter strategy would take more time. It also

appears that men use what has been called a

leaping strategy, whereas women use a conser-

vative strategy. To understand these strategies,

look at the mental rotation task shown in the

middle of Figure 4.4. The respondent is asked

to find which of the four response stimuli cor-

respond to the standard stimulus. The idea is

that men find the two matching stimuli and

then move on to the next item on the test,

whereas women examine all four stimuli to en-

sure that they have found the correct matches

which takes more time. To test this possibil-

ity, Hirnstein, Bayer, and Hausmann (2009)

modified the mental rotation task for college

not a single construct. Think of all the activi-

ties that involve spatial skills: reading maps,

doing jigsaw puzzles, trying to pack all your

belongings from school into the trunk of a

car, and finding where you put your keys.

Given the diversity of tasks that involve spa-

tial skills, it is no surprise that the results of

sex comparisons depend on the type of spa-

tial skill.

Voyer, Voyer, and Bryden (1995) con-

ducted a meta-analysis on the three distinct

spatial skills shown in Figure 4.4. They found

moderate sex differences for spatial percep-

tion(d=+.44) and mental rotation(d=+.56),

but only a small difference for spatial visu-

alization(d=+.19). Thus the size of the sex

difference in spatial skills ranged from very

small to medium, depending on the particu-

lar skill. Since the publication of this meta-

analysis, more recent studies have confirmed

this finding. For example, a study of 16- to

18-year-olds in the United Kingdom showed

large sex differences in mental rotation (d=

1.01) and moderate sex differences in spatial vi-

sualization (d=+.42; Kaufman, 2007). A study

of college students in Norway showed large sex

differences in mental rotation(d=+.85) and

moderate sex differences in spatial visualiza-

tion(d=+.48; Nordvik & Amponsah, 1998).

These sex differences held even when female

and male technology students with a similar

high school background in math and physics

.8

large

.5

medium

–.5

medium

.2

small

–.2

small

(^0) –.8
large
Men Outperform Women Women Outperform Men
Effect Sizes
FIGURE 4.3 Indication of the strength of effect
sizes (d).
M04_HELG0185_04_SE_C04.indd 109 6/21/11 8:02 AM