Hormonal Mechanisms in Aggression

Archer analysed the results of 230 males over 5 studies and found a low positive correlation between testosterone and aggression.

The type of ppt and the form and measurement of aggression differed substantially between studies.

A meta-analysis of 45 studies established a mean correlation of 0.14 between testosterone and aggression.

Archer et al claim that methodological problems with this study meant that a correlation of 0.08 was more appropriate.

From young adulthood due to its action on brain areas involved in controlling aggression.

Dabbs et al measured salivary testosterone in violent and non-violent criminals. Those with the highest testosterone levels had a history of primarily violent crimes, whereas those with the lowest levels had committed only non-violent crimes.

Lindman et al found that young males who behaved aggressively when drunk had higher testosterone levels than those who did not act aggressive.

The challenge hypothesis proposes that in monogamous species, testosterone levels should only rise above the baseline breeding level in response to social challenges such as male-male aggression or threats to status. As the human species ic onsidered to be monogamous, this would predict that male testosterone levels would rise sharply in response to such challenges. In such situations, a testosterone surge is to be expected, with a consequent increase in aggression, provided that the threat is deemed relevant to reproductive competition (eg. a dispute over a female).

Dabbs et al (1991): Cortisol appears to have a mediating effect on other aggression-related hormones, such as testosterone, possibly because it increases anxiety and the likelihood of social withdrawal.

High levels of cortisol inhibit testosterone levels and so inhibit aggression.

Virkkunen: violent offenders
Tennes and Kreye: violent school children

Their findings suggest that although relatively high testosterone is the primary biochemical influence on aggression, low cortisol also play an important role by increasing the likelihood of aggressive behaviour.

Albert et al claim that despite many studies showing a positive correlation between testosterone and aggression, other studies find no such relationship, particularly those that have compared testosterone levels of aggressive and less aggressive individuals.

In addition, most studies showing a positive correlation have involved small samples of men within prisons, using either self-report measures of aggression or judgement based solely on the severity of the crime committed.

Mazur suggests that we should distinguish aggression from dominance. Individuals act aggressively when their intent is to inflict injury, whereas they act dominantly if their wish is to achieve or maintain status over another.

Mazur claims that aggression is just one form of dominance behaviour. In non-human animals, the influence of testosterone on dominance behaviour might be shown in aggressive behaviour. In humans, however, the influence of testosterone on dominance is likely to be expressed in more varied and subtle ways (eg. through status-striving behaviour).