Discuss the role of testosterone in aggression (16 marks)

What is testosterone?

• sex hormone controlled by the pituitary gland

• mostly produced by men in higher quantities but still produced by women

• optimal levels are beneficial for supporting muscle mass, healthy heart, energy levels etc.

• peaks in the first 4 months of gestation and then picks back up in puberty causing big sex diff (7-8x)

Effects of testosterone?

Physical:

• growth of penis and testes

• deepening of the voice

• getting taller

• masculinises the foetus

Psychological:

• increased exposure in the womb causes male typical behaviour

• exposure for females in the womb causes more masculinisation of traits

• attention, spatial activity

• decreased levels = cognitive decline

effects of testosterone on aggression

increased levels cause more aggression

deceased levels cause less aggression

animal studies - Edwards (68)

• new born female mice given testosterone injections

• began to act more like males (more aggressive)

• However, the same effect did not exist if they were injected as adult mice

animal studies - Bermond et al

• testosterone affects certain types of aggression more (inter-male aggression as a defence to intruders)

animal studies - Wagner et al

• castrated mice were injected with testosterone

• aggression levels dropped when castrated and rose again to pre-castrated levels when testosterone was injected

human studies - Dabbs et al

• found testosterone levels were higher in those convicted of a violent crime

• those with higher testosterone levels were rated higher by other prisoners for being ‘rough’

Van Goozen (97)

• natural experiment on sex-change patients

• questionnaire before either being given testosterone or testosterone suppressants

• M-F were less aggressive

• F-M became more aggressive

Olweus et al

• +ve correlation between testosterone and the likelihood of responding aggressively to provocation

• NOT ACTUAL VIOLENCE

AO3 - mixed evidence

• there is a body of evidence to support

• BUT

• Harrison et al → only some Ps → individual differences

• correlation is not causation

• no correlation with actual violence

• testosterone is involved…

AO3 - what’s missing? and extrapolation from animals

• cant look at testosterone in isolation (not only genetic influence)

• socio-legal context and culture

• humans can suppress aggression

• evidence is clearer for animals

AO3 - issues and debates

• biological reductionism → hormones are not the only influencing force

• bio determinism → not all men commit crimes, violent offenders can be rehabilitated, genes don’t determine a trait, only influence it