hormonal mechanisms of aggression

• hormonal explanation?

  • how biochemistry affects aggression
• what is testosterone?

  • male sex hormone
  • produced from testes gland
• role of testosterone?

  • thought to influence aggression from young adulthood onwards due to its action on brain areas involved in controllong aggression
  • supported by fact men are more aggressive - 10x more testosterone
  • men get less aggressive as they get older - declines across mans lifespan
• link testosterone & serotonin?

  • testosterone acts on serotonin synapses to reduce serotonin transmission
  • links neural & hormonal explanations together
• research into testosterone?

  1. dolan 2001
• dolan 2001?

  • found positive coorelation between testosterone levels & aggressive behaviours in sample of 60 male offenders in uk maximum security hospitals
  • shows hormonal mechanisms do influence aggression
  • when testosterone levels increase so does aggressive behaviour
  • BUT correlation does not equal causation
• 3 * of hormonal mechanisms?

  1. empirical evidence from van goozen et al
  2. evidence to support from dabbs
  3. evidence to support from beeman
• * empirical evidence from van goozen 1995?

  • conducted study to see if changes in testosterone levels altered aggressive behaviour
  • followed sample of transgenser patients before & after hormone therapy
  • bio males to females decreased testosterone levels
  • bio females to males increased levels
  • found tendency for aggression to decrease in male to female transitions/vice versa
  • shows when we experimentally manipulate/alter biochemistry it impacts behaviour
  • high levels of testosterone linked to aggression levels - biological cause
• * evidence from dabbs 1995?

  • measured testosterone levels from saliva of 692 adult male prisoners
  • found there was much higher levels of testosterone in violent offenders - rapists that in non violent who commited petty crime - burglars/theives
  • shows high levels of testosterone linked to increased aggression levels
  • those who were more violent had increased levels adding to validity
• X contradictory evidence from dabbs?

  • study is correlational so its a more ethical way of studyiny hormonal mechanisms in aggression
  • would be unethical to manipulate testosterone levels
  • HOWEVER we dont know whether is is abnormality with hormones which causes aggression or whether person is already aggressive which changes their hormonal structure
  • may be other factors involved - childhood upbringing
  • affects aggression
• evidence from beeman 1947?

  • castrated male mice reducing levels of testosterone so aggressivess reduced
  • later injected mice with testosterone which re-established their aggression
  • shows testosterone does influence aggression
  • when castrated testosterone levles decreased showing less aggression
  • reinforces hypothesis that high levels of testosterone increase aggression
• X contradictory evidence from beeman?

  • more ethical to research on animals
  • too unethical to castrate human males to lower their levels of testosterone to see effect this would have on aggression - breaks protection from harm
  • HOWEVER difficult to generalise findings to humans as our biology is much more complex & we have different intellectual/social/emotional experiences that affect behaviour
  • so cannot say that having higher level of testosterone in humans will cause aggression same as mice
• X biologically deterministic?

  • pro: cause & effect so empirical & used to develop practical applications to treat agg
  • allows us predict & prevent future behaviour eg identify whos at risk look at levels of hormone & meds to prevent imbalance
  • con: implies that agg caused by biochem - out of our control/not in free will
  • potential socially sensitive - criminals absolved - less responsible - biochem/hormone
  • may upset/offend victims/families
  • feel removal of blame minimises significance of trauma
  • excuse/normalise agg in others
  • males naturally have more testos -lead to negative stereotyping