Aggression 1 | Neural and hormonal mechanisms in aggression Flashcards
AO1: What is the role of the limbic system in aggression?
The limbic system regulates emotional behaviours such as aggression. Key structures include the amygdala which is involved in evaluating emotional significance of stimuli and the hypothalamus which can trigger aggressive responses.
AO1: How does the amygdala contribute to aggression?
The amygdala assesses threats and generates an aggressive response if needed. Overactivity in the amygdala has been linked to increased aggression.
AO1: What is the role of serotonin in aggression?
Serotonin has an inhibitory effect on aggression. Low levels of serotonin are associated with increased impulsive and aggressive behaviour due to reduced ability to regulate emotional responses.
AO1: What is the role of testosterone in aggression?
Testosterone is a male sex hormone associated with increased aggression. It may influence areas of the brain such as the amygdala
AO1: What is the MAOA gene and its role in aggression?
The MAOA gene regulates the enzyme, monoamine oxidase A which breaks down neurotransmitters such as serotonin. A low-activity variant of MAOA (MAOA-L) is linked to aggressive behaviour due to impaired serotonin regulation.
AO3: What did Brunner et al 1993 find?
They studied a Dutch family with a history of violence and found that the men had a low-activity version of the MAOA gene. This was linked to impulsive and aggressive behaviour.
AO1: What did Caspi et al 2002 find about the MAOA gene and aggression?
They found that males with the MAOA-L variant were more likely to exhibit aggressive behaviour but only if they had been abused as children. This supports a diathesis-stress model.
AO1: What did Christiansen 1977 study and find?
He studied 3586 twin pairs in Denmark. Concordance rates for criminal behaviour were 35% in MZ twins and 12% in DZ twins. This suggests a genetic component to aggression.
AO1: What are the conclusions and evaluation points of Christiansen 1977?
There is a genetic basis to aggression but the concordance is not 100% indicating the role of environment. Twin studies may also suffer from shared environment confounds.
AO3: What did Moeller et al find about serotonin and aggression?
Moeller et al found that individuals with lower levels of serotonin showed more impulsive and aggressive behaviours. This supports the inhibitory role of serotonin.
AO1: What did Van Goozen et al 1994 study and find?
They studied trans individuals undergoing hormone treatment. Female-to-male trans people receiving testosterone showed increased aggression while male-to-female trans people receiving oestrogen showed decreased aggression.
AO1: What are the conclusions and evaluation points of Van Goozen et al 1994?
Supports the role of testosterone in increasing aggression. However
AO3: What is one strength of serotonin as an explanation of aggression?
Studies like Virkkunen et al found low serotonin metabolite levels in violent offenders which supports the idea that low serotonin leads to impulsive aggression.
AO3: What is one strength of the limbic system explanation?
fMRI studies such as Gospic et al found that heightened amygdala activity was linked to aggression and reduced when benzodiazepines were given. This supports the biological basis of aggression.
AO3: What is one strength and one limitation of testosterone in aggression?
Strength: Dolan et al found a correlation between high testosterone levels and aggression in violent offenders. Limitation: Correlation does not mean causation and other factors may be involved.
AO3: What is a strength of genetic explanations of aggression?
Brunner et al found a link between the MAOA-L gene and violence in a Dutch family. This supports a genetic influence on aggression.
AO3: What is a limitation of genetic explanations of aggression?
Caspi et al showed that MAOA-L only led to aggression when paired with childhood abuse. This supports a diathesis-stress model and suggests genes alone are not sufficient.
AO3: What is an evaluation of Christiansen 1977’s twin study?
Genetic contribution is supported by higher concordance in MZ twins
AO3: What is an evaluation of Van Goozen et al 1994?
Supports testosterone’s role in aggression but findings are correlational and hormone treatment effects may vary by individual or context.
AO3: Charles Whitman as a strength of the limbic system in aggression.
A sniper who killed 14 innocent people and injured 31, an autopsy showed a temporal lobe tumour pressing on his amygdala
AO3: What did Dabbs et al. (1987) find in their study on testosterone and aggression?
Dabbs et al. (1987) measured testosterone levels in male prisoners and found that those with higher levels were more likely to have committed violent crimes (e.g., assault, murder). They were also rated as more aggressive by prison staff. This suggests a link between high testosterone and aggressive behaviour.
