The biological explanations of aggression say that aggression is caused by differences in the biological make-up of individuals. One example of these biological differences that could cause aggression is neural mechanisms.
Neurotransmitters are chemicals which trigger a response in the brain, serotonin and dopamine are both examples of neurotransmitters which are thought to influence aggression levels.
Serotonin – Psychologists believe that low levels of serotonin, known as the body’s natural ‘happy drug’, can lead to an increase in aggression levels. This is because serotonin is thought to inhibit our response to emotional stimuli that might otherwise lead to aggressive behaviour, so low levels of serotonin mean we will respond aggressively more often.
Dopamine – We are unsure of whether there is a causal link between dopamine and aggression, however research has found a relationship between the two. For example, Lavine (1997) found that an increase in dopamine levels through the use of amphetamines was associated with an increase in aggressive behaviour, suggesting that higher levels of dopamine correlate with higher levels of aggression.
Mann et al – found that after being given dexfenfluramine, which reduces serotonin levels, participants reported higher levels of aggression. However, this was only found in males.
Bond (2005) – said that if low levels of serotonin cause aggression then drugs that increase the level of serotonin should result reduced aggression, and her research found exactly this.
Dopamine levels a consequence of aggression – Couppis and Kennedy (2008) found that in mice dopamine levels will increase and act as a reward during an aggressive act. This could mean that the increased levels of dopamine are not a cause of aggression but a consequence of it.