Neural Mechanisms

Neural Mechanisms

1. Chemicals that allow implies in the brain to be transmitted from one part of the brain to another

2. Serotonin

   • Believed to reduce aggression by inhibiting responses to emotional stimuli that might otherwise have led to an aggressive response. Low levels of serotonin in the brain have been associated with an increased susceptibility to impulsive behaviour, aggression & violent behaviour

3. Dopamine

   • High levels of dopamine are believed to cause aggression in individuals - use of amphetamine drugs been shown to increase aggression in normal people. - Antipsychotics which reduce dopamine activity in the brain, shown to reduce aggressive behaviour in violent delinquents (Buitelaar,2003)

4. Support

   • Mann et al: individuals with increased numbers of pre-frontal cortex serotonin receptors
     • 35 healthy subjects given drug that depleted serotonin levels judging their aggression based on hostility scores on a questionnaire- found that lower levels of serotonin were found to be associated with higher levels of aggression in males but not females
   • Raleigh et al (1991) study of vervet monkeys, fed on experimental diets high in tryptophin (increases serotonin levels in the brain) exhibited decreased levels of aggression - those fed on diets low in tryptophan exhibited increased aggressive behaviour. Aggression attributed to their serotonin levels
   • Ferrari et al: Rats fought over 10 days at exactly the same time, 11th day animal did not fight & researchers measured levels of serotonin despite the animals not fighting that day
     • found elevated levels of dopamine & decreased levels of serotonin- believed experience had changed animals brain chemistry by altering serotonin & dopamine levels

5. Against

   • Reductionist: research into how neural factors may cause aggression argued to be reductionist as they ignore role of cognitive and psychological factors- Not everyone with hormonal imbalance is aggressive
   • participants may have displayed demand characteristics, expecting themselves to behave more aggressively due to taking drugs that deplete serotonin levels- behaviour measured may be inaccurate
   • Gender bias: most research is based on male participants- generalisation to women not always possible
   • Deterministic: ignores role of free will people have & ability of conscious thoughts that allows them to override such impulses and control behaviour
   • argued unethical & morally wrong- unethical concerns due to potential suffering inflicted
   • uncertain in animal studies if any findings can be generalised to humans due to the vastly different biology & anatomy between species