138 Chapter 5influence behavior. Girls with CAH are often
born with male genitalia, a condition usually
altered with surgery. Thus the parents and
the children are aware of prenatal exposure
to androgens. Parents might expect the CAH
child to exhibit more masculine behavior,
provide the child with more masculine toys
and masculine activities, and respond more
favorably to masculine behavior displayed
by the child. The child herself also might be
more comfortable engaging in masculine
activities because of her own awareness of
the exposure to male hormones. It is difficult
to disentangle this issue from the research.masculine social behavior, and homosexu-
ality (Puts et al., 2008). First, androgens
could affect areas of the brain that are linked
to spatial skills, masculine social behav-
ior, and sexual orientation. Second, andro-
gens could affect the tendency to engage in
activities that affect cognition and behav-
ior. For example, androgens make children
more active, which then lead them to more
masculine-type behavior. A specific social
behavior that has been linked to activity and
male hormones is aggression. See Sidebar 5.1
for a discussion of this issue. Third, the mas-
culinization of appearance could somehowSIDEBAR 5.1:Does Testosterone Cause Aggression?
Hormonal explanations for male violence often center on the male hormone, testosterone,
which has been linked to frustration, impatience, impulsivity, high levels of physical activity,
and sensation-seeking (Harris, 1999). But, is there any evidence that testosterone is linked to
violence? A meta-analysis of 54 samples showed a weak but positive relation of testosterone to
aggression (d= +.28; Book, Starzyk, & Quinsey, 2001). For males, the relation decreased with
age such that the largest effect was observed among 13- to 20-year-olds (d= +.58). The most
aggressive behavior seems to be linked to a combination of high testosterone and low cortisol
(Terburg, Morgan, & van Honk, 2009). Studies of male prisoners have found that testosterone
levels are higher among men who committed personal crimes of sex and violence than those who
committed property crimes of burglary, theft, or drugs (Dabbs et al., 1995) and among men who
committed more ruthless crimes (i.e., premeditated; Dabbs, Riad, & Chance, 2001). In addition,
prisoners with high testosterone levels were more likely to have violated prison rules.
Thus a relation exists between aggression and testosterone, but the evidence is far from clear
that testosterone plays any causal role in aggression. This area of research is largely correlational.
Does testosterone cause aggression, or does behaving aggressively lead to a rise in testosterone?
Or is there a third variable responsible for both? Competitive situations may be one such variable.
In a study of college students, testosterone was measured prior to playing a competitive game
(McDermott et al., 2007). Men made higher unprovoked attacks during the game than women,
as did people who had higher levels of testosterone. Thus, testosterone appeared to account for
the sex differences in aggressive behavior. Hormones also interact with situational factors, such
as a threat to status or competition, to produce aggressive behavior (McAndrew, 2009). Some
situational factors, such as noise or alcohol, could exacerbate the effects of hormones on aggres-
sion, whereas other situational factors, such as the knowledge the behavior is inappropriate for a
specific situation, could inhibit the effect of hormones on aggression. See Figure 5.2 for a plausible
model of how situational factors interact with biology to influence aggressive behavior.M05_HELG0185_04_SE_C05.indd 138 6/21/11 8:03 AM