AO1 1 - Serotonin
Serotonin = reduce aggression by inhibiting responses to emotional stimuli that may have otherwise led to an aggressive response
Low levels of the brain (pre frontal cortex) has been linked with more impulsive behaviours
AO2 1 Mann
- 35 healthy subjects a drug that depleted serotonin levels.
- Measured aggression based on hostility scores measured by a questionnaire.
- Lower levels of serotonin found to be associated with increased levels of aggression in males but not females.
AO1 2 Dopamine
High levels of dopamine are believed to cause aggression.
Support = use of amphetamie drugs which have been shown to increase aggression levels in normal people.
AO2 2 Anti psychotics
- anti psychotics - reduce dopamine levels
- reduce aggression
AO2 3 Couppis and Kennedy
- dopamine is produced as a response to rewarding stimuli
- Couppis et al
- some individuals may intentionally seek out aggressive encounters because of the dopamine release they are rewarded with
AO1 3 Testosterone
- high levels increase aggression
- When testosterone levels peak around the start of puberty - peak in aggression levels
- suggests a correlational link
- cannot be sure of cause and effect
AO1 4 Cortisol
- mediating effect on hormones such as testosterone
- higher levels increase anxiety and inhibits testosterone levels
- violent offenders have lower levels
AO2 4 Raleigh
- fed vervet monkeys diets that increased or decreased serotonin level
- decreased serotonin - more aggressive behaviour
AO2 5 Scerbo and Raine
- Meta analysis examining neurotransmitter levels in in anti social children and adults.
- lower levels of serotonin were found in aggressive individuals
- no difference in dopamine levels
AO2 6 Reductionist
- link between neural mechanisms criticised for being reductionist.
- complexity of human behaviour means biological explanations are insufficiant on their own to explain aspects of human aggression.
- e.g. Bandura found that SL has a powerful influence on aggression in children
AO2 7 Albert
- link between T and A is inconclusive
- Albert - many studies showing a possible correlation are based on small samples of men in prisons using self reports
- Lack internal validity
Ao2 8 McBurnett
Importance of cortisol
- McBurnett et al
- children with low cortisol levels were 3x more likely to be aggressive sooner than those with higher levels
- However link is correlational
- can not be certain of cause and effect - unknown variables may be responsible
IDA Gender bias
- most research based on male participants
- generalisation to women is not always possible