Hormonal Mechanisms in Aggression

Hormonal Mechanisms in Aggression

1. Testosterone

   • Male sex hormone thought to influence aggression due to it’s effects on brain areas involved in controlling aggression.
   • Dabbs et al
     • Supportive. Measured salivary testosterone levels in violent & non-violent criminals.
     • Highest=history of primarily violent crimes. Lower=non-violent crimes.
   • Lindman et al
     • Supportive. Young males behaved aggressively when drunk had higher testosterone levels than those who didn't
   • 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.
     • Social cues

2. Testosterone

   • Archer
     • 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.
   • Albert et al
     • Refutive. Studies have found a link between testosterone and aggression, but others haven’t. Thus, there is inconsistent evidence.

3. Cortisol

   • 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.
   • Virkkunen
     • Reported low levels of cortisol in habitual violent offenders
     • Tennes &Kreye
       • Low levels of cortisol in violent schoolchildren.

4. Cortisol

   • 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. IDAs

   • 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
   • 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.