The Psychology of Gender 4th Edition

142 Chapter 5

it help to remedy any deficits found in one

sex compared to the other (Halpern, Wai, &

Saw, 2005). Halpern and colleagues propose

an alternative theory to the traditional nature

versus nurture model of sex differences—the

psychobiosocial model. They argue that na-

ture and nurture are not two mutually exclu-

sive categories, but categories that interact

with one another. As shown in Figure 5.3,

biological factors operate within a social con-

text. Even if biological differences exist, the

environment can still exert an influence, and

an important one at that!

TAKE HOME POINTS

■ Twin and adoption studies conclude that genes play a

role in sex differences in cognition and social behavior

as well as gender-related behavior, but that role is far

from 100%.

■ The strongest evidence for links of sex hormones to

cognition and behavior is in research that has shown

of the brain. However, a sex difference in a

brain structure does not translate into a sex

difference in a brain function (de Vries &

Sodersten, 2009). As indicated earlier, a sex

difference in an area of the brain does not

always lead to a sex difference in behavior.

Different structures or differential brain ac-

tivation can lead to the same behavior. In

addition, the brain is not constant, as behav-

ior can alter the brain, as indicated by the

following study of juggling. One group of

young adults was taught how to juggle over

a three-month period, and one group was

not. Despite the fact that brain scans showed

no differences between the two groups prior to

the study, differences in brain structure related

to motion processing emerged after three

months for the juggling group (Draganski

et al., 2004). However, the brain structure dif-

ference disappeared when juggling ceased.

Thus, the meaning of sex differences in brain

structure is not yet fully understood.

Not surprisingly, researchers also have

examined whether different areas of the

brain can be linked to gender identity. A

study of male to female transsexuals on au-

topsy showed that one area of the brain—the

hypothalamic uncinate nucleus—appeared

more similar to that area of the brain in

women than men (Garcia-Falgueras &

Swaab, 2008), suggesting a biological basis

for gender identity.

Psychobiosocial Models

A common objection to biological theories

of sex differences and gender-related behav-

ior is that any biological differences found

between women and men will be used to jus-

tify the inferior status of women in society.

However, ignoring biological differences be-

tween men and women will not help to un-

derstand cognition and behavior—nor will

Genetic Predispositions Brain and

Other Central Nervous

System

Development

Inte

rnal Change

s

(e.g.

,h

ormone sec

retio

ns)

Learning

Thoughts

Beh

aviors

Experiences/

Environments

FIGURE 5.3 Psychobiosocial model showing

the interrelation between biological, psychological,

and social influences.

Source: Halpern, Wai, and Saw (2005).

M05_HELG0185_04_SE_C05.indd 142 6/21/11 8:03 AM