Male sex hormone thought to influence aggression due to it’s effects on brain areas involved in controlling aggression.
1.1 Dabbs et al
Supportive. Measured salivary testosterone levels in violent & non-violent criminals.
Highest=history of primarily violent crimes.
1.2 Lindman et al
Supportive. Young males behaved aggressively when drunk had higher testosterone levels than those who didn't
1.3 Wingfield et al
Proposes that in monogamous species, testosterone should only rise above baselines breeding level in response to social challenges e.g. threats to status. Thus, testosterone surges is expected with a consequent rise in aggression.
Supportive. Meta-analysis. 230 males over 5 studies
Found a low, but positive correlation between testosterone and aggression. However, type of Pps, and form and measurments of agression differed substantially between studies.
Correlational data only shows causal data, but not why.
2.2 Albert et al
Refutive. Studies have found a link between testosterone and aggression, but others haven’t. Thus, there is inconsistent evidence.
Has a mediating effect on other aggression-related hormones like testosterone, possibly as it raises anxiety and liklelihood of social withdrawel.
Low cortisol plays an important role by raising likelihood of aggressive behaviour.
Reported low levels of cortisol in habitual violent offenders
3.1.1 Tennes &Kreye
Low levels of cortisol in violent schoolchildren.
4.1 Four year study on boys with behavioural issues.
Supportive of the moderating effect of cortisol on aggressive behaviour.
Boys with consistently low cortisol levels began anti-social behaviour at a younger age, plus exhibited 3 times aggressive symptoms than boys with higher cortisol.
Thus, cortisol is ‘strongly and inversly related to aggressive conduct disorder’.
5.1 Gender Bias
Research suggests a link between testosterone and aggression higher for females. Females may also respond to challenging situations with increased testosterone, displaying aggression
5.2 Reductionism & Biological Mechanisms
The links between biological mechanisms like testosterone with aggression isn’t as well established in humans. Complexity of human social behaviour means a biological explanation for aggression is insufficient on it’s own to explain all aspects of aggressive behaviour.