Discuss the role of neural and hormonal mechanisms in aggression.

There are two hormones associated with an increase in aggressive behaviour; testosterone and cortisol. Hormones are chemicals that regulate and control bodily functions and testosterone is one of the androgen hormones due to the fact it produces male characteristics. It is suggested that high levels of testosterone lead to aggressive behaviour.

Van Goozen et al (2007) claim that there is a link between aggression and the hormone cortisol. They believe that the relationship between cortisol and aggression is an inverse correlation as lower levels of cortisol are associated with higher levels of aggressive behaviour. This is due to the fact that cortisol appears to have an important mediating influence on other aggression-related hormones such as testosterone, by inhibiting the likelihood of aggressive behaviour. A study by Popma et al (2006) found a significant positive relationship between testosterone and aggression but only in participants with low cortisol levels vs. high. An alternative explanation of this link between low cortisol and aggression is that low autonomic nervous system arousal, and therefore low cortisol, is experienced as being unpleasant. As a result, aggressive behaviour becomes an attempt to create a stressful situation in order to provoke autonomic nervous system activation and cortisol release.

The explanation that demonstrates the link between neurotransmitters and aggression is arguably reductionist. This explanation largely ignores the important role played by social factors in aggression. For example, research by Bandura et al showed that social learning can be a powerful influence on the aggressive behaviour of children, and Zimbardo et al has provided support for the idea that deindividuation can increase aggressive behaviour in particular situations where personal responsibility is diminished. Such studies demonstrate that there are clearly other important factors involved in aggressive behaviour, making the genetic explanation reductionist. The genetic explanation is insufficient on its own to explain the many different aspect of human aggressive behaviour. It completely overlooks the complexity of humans and aggressive behaviour and therefore is incredibly reductionist.

In understanding both the neural and hormonal mechanisms and their role in aggression has practical applications. By knowing that aggressive behaviour is a product of decreased levels of serotonin in the brain then It could be possible to treat aggression by administering SSRI’s which would increase the amount of serotonin in the synapse. Such treatment is actually already being used today and these drugs are being used effectively to control violent behaviour in selective groups such as elderly patients with dementia living in residential nursing homes, and aggressive children. In addition, the link between testosterone and aggression has been used to inform the argument why the presence of guns in the environment may increase aggression. The presence of certain stimuli such as guns or knives, trigger increases in testosterone, with an associated rise in traits such as aggressiveness and dominance. This kind of information could therefore be made well known to those trying to control their anger and they could then attempt to remove any of the stimuli that might trigger a rise in testosterone and therefore cause violent behaviour as a first step.

Research into the links between testosterone with aggression has raised many issues. To start much of the research conducted is which means it’s hard to establish cause or affect. It is hard to tell, for instance, whether a raised level of testosterone is a result of a person acting aggressively or the other way round. Yet correlational research is not the only problem. A lot of research into this link is conflicting. A number of studies have found that high levels of testosterone correlate positively with high levels of aggression, but other studies have not found such a relationship. For instance, Bain et al found no significant differences in testosterone levels between men who had been charged with murder or violent assault and men who had been charged with non-violent crimes such as burglary. In some cases, higher levels of testosterone have actually appeared to have a positive affect on individuals rather than a negative, aggressive one. For instance, Zitzmann (2006) argues that not only is the link between testosterone and aggression not proven, but that testosterone may also have many positive effects for males. For example, increases in positive mood and decreases in negative mood were confirmed following testosterone replacement therapy in a study of 208 men with testosterone deficiency. Therefore there are clearly issues with research into the link between testosterone and aggression and the conflicting research calls into question the reliability of the neural explanation of aggression.