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the growth spurt that occurs during puberty. Both estrogen and progesterone are also involved in
pregnancy and the regulation of the menstrual cycle.
Recent research has pinpointed some of the important roles of the sex hormones in social
behavior. Dabbs, Hargrove, and Heusel (1996) [1] measured the testosterone levels of 240 men
who were members of 12 fraternities at two universities. They also obtained descriptions of the
fraternities from university officials, fraternity officers, yearbook and chapter house photographs,
and researcher field notes. The researchers correlated the testosterone levels and the descriptions
of each fraternity. They found that the fraternities with the highest average testosterone levels
were also more wild and unruly, and one of these fraternities was known across campus for the
crudeness of its behavior. On the other hand, the fraternities with the lowest average testosterone
levels were more well behaved, friendly and pleasant, academically successful, and socially
responsible. Banks and Dabbs (1996) [2] found that juvenile delinquents and prisoners who had
high levels of testosterone also acted more violently, and Tremblay et al. (1998) [3] found that
testosterone was related to toughness and leadership behaviors in adolescent boys. Although
testosterone levels are higher in men than in women, the relationship between testosterone and
aggression is not limited to males. Studies have also shown a positive relationship between
testosterone and aggression and related behaviors (such as competitiveness) in women (Cashdan,
2003). [4]
It must be kept in mind that the observed relationships between testosterone levels and
aggressive behavior that have been found in these studies do not prove that testosterone causes
aggression—the relationships are only correlational. In fact, there is evidence that the
relationship between violence and testosterone also goes in the other direction: Playing an
aggressive game, such as tennis or even chess, increases the testosterone levels of the winners
and decreases the testosterone levels of losers (Gladue, Boechler, & McCaul, 1989; Mazur,
Booth, & Dabbs, 1992), [5] and perhaps this is why excited soccer fans sometimes riot when their
team wins.
Recent research has also begun to document the role that female sex hormones may play in
reactions to others. A study about hormonal influences on social-cognitive functioning (Macrae,
Alnwick, Milne, & Schloerscheidt, 2002) [6]found that women were more easily able to perceive