©Arlene Taylor PhD

Brain Type Impact

Testosterone appears to an important variable in determining brain type or sex-typical behavior. There are three developmental periods when testosterone secretion surges: the prenatal period between 8-24 weeks, 5 months after birth, and at puberty. For example, the nature/nurture combination impact can be seen in the connection between testosterone and aggression. Metaphorically, think of the testosterone-assertiveness connection using the metaphor of a radio. Imagine that each of us is a radio and that we are born with the power switch turned on. Testosterone is the volume-regulator (at least for assertion and aggressiveness). The higher the level of testosterone, the greater the tendency to exhibit assertive or aggressive behaviors.

Assertiveness Impact

In addition to surges related to developmental periods, testosterone secretion increases in the presence of any form of competition including active participation in a competitive situation, or virtual participation through observation (although the relative rise appears to be much more dramatic in the male body than in the female body). Assertive/aggressive behaviors tend to escalate in both genders as testosterone levels rise. Since testosterone tends to increase in presence of competition, dating after an exciting competition (e.g., football game, track and field competition) can be a dangerous affair. This phenomenon may also play a factor in date rape.



• Overall, females are less assertive and lose their temper half as often (likely due to a combination of lower testosterone levels and socialized expectations).

• Hormones appear to provide some protection against specific diseases (e.g., heart disease) prior to menopause.

• Males are generally more assertive (likely due to higher testosterone levels) and lose their temper twice as often.

• Males experience a type of menopause and tend to handle this more easily if they experienced an unhappy childhood.

NOTE: Males and females have identical hormones in their bodies. The relative levels differ, however. In females, the estrogens and progesterone dominate. At puberty, testosterone levels in the female body may be only 1/20th of the levels found in the bodies of comparable males. In males, testosterone dominates. Overall testosterone levels may be 10-15 times higher. At puberty, male testosterone levels may be 20 times higher than levels in the bodies of comparable females.