What causes aggression?

Biological explanations

Hormones: One explanation for aggression is that it is caused by hormones, most particularly testosterone. There is more testosterone in males than in females and is found in even higher levels in violent criminals.

Chromosomes: Violent criminals are often found to have chromosomal abnormalities i.e. a high number of criminals have an extra Y-chromosome. It is believed that this XYY structure may cause more aggression.

Brain disease can affect the limbic system and/or the prefrontal cortex, parts of the brain which deal with the way we behave. The limbic system is associated with aggression and the prefrontal cortex serves to control this aggression. When these mechanistic controls break down the individual can lose control of his behaviour.

Psychodynamic explanations

Sigmund Freud famously believed that humans are driven by strong unconscious aggressive instincts which the more rational part of our mind controls. This rational part of our mind, sometimes called the ego, is therefore important in making us behave in a socially acceptable way. On occasion, however, the ego can fail and we can become dangerously aggressive.

Ego defence mechanisms: Later psychologists developed this theory by suggesting that we may have aggression building up inside us, but that this aggression only spills out when something frustrates us. Something as simple as spilling a drink or getting stuck in traffic can trigger aggression which we burn off by shouting, swearing or hitting something.

——————————————————

Social learning theories

This is the theory that people learn their behaviour by observing others. Children are particularly likely to imitate role models, older siblings, peers or their parents. If they witness aggressive behaviour and see that the outcome is positive, it is likely that they will take on this form of behaviour too. Action heroes in film and video games may cause individuals to behave more aggressively. They may also witness people getting their way when aggression is used. Children may even learn aggression from parents when they use physical forms of punishment in the home.

Monitoring: Social learning doesn’t always have to be external. People will also monitor their own behaviour and judge whether this kind of behaviour has made them feel good or bad. If a certain course of behaviour tends to give us a negative feeling then we are not likely to repeat this behaviour in the future. If an act of aggression has made us feel good there is a strong chance that we will behave in this way again.