neural mechanism in aggression

neural mechanism in aggression

1. Serotonin

   • low levels of serotonin have been linked to increased impulsive and agressive behaviour
   • It usual prevents the stimulation of the amygdala, a structure associated with aggression, if there are low levels of serotonin there is less inhibition of the amygdala and as a result becomes more active when stimulated by external events
   • AO2/IDA
     • Mann study
       • they administered drugs which lower levels of serotonin to particapants, they then used a questionnaire to assess hostility and aggression levels
       • Aggression levels were raised in males and not females. this may suggest it is more important in males than females.
     • Study on dog breeding
       • Popova et al found that among dogs that have been selectively bred for domestication and for increasingly docile temperament, there has been a corresponding increase in brain serotonin.
       • This suggests that there is a link between low levels of serotonin and high levels of agression
       • However these results cannot be generalised to humans as our brain structures are different, and we would react differently to the changes dues to external factors like social and cultural cues.
     • Antidepressant evidence
       • Further evidence comes from use of drugs to raise levels of serotonin, such as antidepressants
       • Antidepressant drugs which raise serotonin levels (SSRI's) also tend to reduce irritability and impulsive aggression.
       • this suggest that increased serotonin levels do lead to reduced aggression, however this is a correlational study and we cannot assume cause and effect

2. Dopamine

   • There appears to be a link between dopamine aggression although the link isnt as clear as it is with serotonin
   • it appears that increased dopamine levels can produce increased levels of aggressive behaviour
     • For example the increased rates of agressive behaviour have been found in schizophrenics, and also people who take amphetamine as it increases dopamine levels
   • AO2/IDA
     • Evidence from antipsychotics
       • Correlational research
         • A lot of the research into dopamine and aggression is correlational and we need to be careful at assuming cause and effect.
         • A study by Couppis and Kennedy found that dopamine may be the consequence of agression rather than the cause.
       • Antipsychotic drugvs reduce the amount of dopamine, studies have generally found that the use of these drugs reduces the incidents of aggressive behaviour , thus suggesting that decreased dopamine leads to decreased aggression
     • Reductionist
       • the complexity of human behaviour means that biological explanations are insuffiicent on their own to explain the different aspects of human aggression