Biological explanations of crime: Amygdala

What if the function of the amygdala?

The amygdala processes information from our senses and determines how we respond to that information. It is stimulated when we face a perceived threat. If in a threatening situation, the amygdala will send information to other parts of the brain to prepare the body to either face the situation or get away from it.

What triggers the flight-or-flight response?

Triggered by emotions of fear, anxiety, aggression and anger.

What happens when the amygdala acts too strongly?

It can cause amygdala hijacking.

Typically, in a stressful situation, the temporal lobes will step in to override the amygdala and ensure we respond to a situation appropriately. But, if the situation causes strong feelings of anxiety, aggression, anger or fear this can result in illogical and irrational overactive behaviours being displayed.

Essentially, the amygdala overrides the frontal lobes to hijack stress response control and this can cause us to act inappropriately.

Strengths of the theory?

• Raine et al (1997)

• Pardini et al (2014)

Why is Raine et al (1997) a strength?

Provided evidence to show that the amygdala might have a role in criminal behaviour. Raine found significant differences in the brain structure or murderers and non-murderers, including differences in subcortical areas such as the amygdala. Murderers showed asymmetrical activity in their amygdalae with lower activity in the left amygdala and more activity in the right amygdala compared to non-murderers.

Why is Pardini et al (2014) a strength?

Provided evidence to show that the amygdala might have a role in criminal behaviour. The 3 year longitudinal study used brain scans of men with a history of violent behaviour. It found that men with smaller amygdalae were three times as likely to exhibit aggression, violence and psychopathic tendencies when assessed at the end of the 3 year period. Pardini and his colleagues therefore concluded that the volume of the amygdala might be a biomarker for people displaying severe and persistent aggression in the future.

Weaknesses of the theory?

• Research conducted in this area is usually on animals, which may lack generalisability to humans

• The amygdala cannot be isolated from other brain areas (Bower and Price - 2001)

How is animal research a weakness?

A problem with research in this area, particularly studies on ‘Sham rage’ is that they are conducted on animals and therefore may lack generalisability to humans. Animals, unlike humans, do not have to capacity to limit their aggression with higher order thinking, so findings can only be applied to humans.

How is Bower and Price (2001) a weakness?

A weakness on focusing on the amygdala as. source of aggressive behaviour is that it cannot be isolated from other brain areas. Research suggests that the amygdala does not operate alone, but is heavily influenced by the orbitofrontal cortex (OFC) which is a part of the frontal lobe and not the limbic system. For example, Bower and Price (2001) showed that damage to the OFC led to increased aggression and loss of control. Therefore, this suggests that different crimes or criminals may have influences from more than one brain areas, so making direct links between the amygdala and crime is difficult.