role of hormones in human behaviour

• o   Hormones are a chemical substance that circulates in the bloodstream and only affects target organs, produced in large quantities but disappear quickly.

  o   The effect of hormones is very powerful and widespread in the body.
• o   Testosterone is a sex hormone more commonly found in males and has a role of regulating social behaviour through its influence on areas of the brain implicated in aggression.

  o   Testosterone appears to be influential during two life periods: a few days after birth, during which sensitisation of neural circuits occurs, and in adulthood when testosterone modulates neurotransmitter pathways.
• o   The dual hormone hypothesis proposed by Mehta claims that high levels of testosterone only lead to aggression when there are low levels of cortisol in the bloodstream, with high levels of cortisol, the influence of testosterone in causing aggression is blocked.
• o   Adrenaline is produced in the adrenal glands and is the body’s acute stress response system. It causes the body to increase heart rate, blood flow and pupil dilation ready for a ‘fight or flight’ response.

  This shows that hormonally control of aggression may be more complex than saying just one hormone influences aggression.
• A strength is that there is evidence to support the link between the levels of testosterone and aggression. In a study conducted by Dabbs, where they took samples of saliva and found that there was the same effect of testosterone in males and female prisoners. This is a strength as it shows that aggression isn’t about gender but the levels of testosterone in a person that leads to aggressive behaviour.
• A weakness is that research into hormones can be seen as simplistic by saying that complex human behaviours can all be explained by a single hormone, testosterone. For example, the effect of testosterone can be modified by another hormone, cortisol, in response to stressful situations.
• [weakness justification] This is a problem because, explaining behaviours in terms of basic biological units such as hormones, we might not consider other factors such as gender and personality which may also affect aggression. However, by isolation testosterone, and finding drugs that reduce the effect of testosterone, we can use it with many violent people to reduce testosterone at an early stage and make them less aggressive.