Hormonal Mechanisms

Question 1

Androgen Definition

Answer 1

• Controls development of male characteristics

Question 2

Why has androgen been linked with aggression?

Answer 2

• Many people have observed that men are generally more aggressive than women
• Men become more aggressive towards other men at a time in development (after 20 years) when testosterone levels are highest (Daly and Wilson in 1998)
• Testosterone has a role in regulating social behaviour via its influence on certain areas of the brain implicated in aggression

Question 3

Giammanco et al (2005)

Answer 3

• Castration studies of animals show that removing the testes (source of testosterone) reduces aggression in the males of many species – giving injections of testosterone to the same animals restores aggressive behaviour

Question 4

Dolan et al (2001)

Answer 4

• Found a positive correlation between testosterone levels and aggressive behaviours in a sample of 60 offenders (men) in UK maximum security hospitals – these men mostly had personality disorders (like psychopathy) and histories of impulsively violent behaviour

Question 5

Nelson (1995)

Answer 5

• Reviewed research into how hormones influence aggressive behaviour
• There does seem to be a positive correlation between the levels of androgens circulating in the body and aggressive behaviour in male and female prisoners – this supports hormonal theory of aggression as it suggests that specific hormones (testosterone) are implicated in aggressive behaviour
• However, it is unclear whether the androgen level was caused the aggression as it was not measured at the precise point when the aggressive act was being produced – it could be that aggression causes an increase in testosterone levels rather than the other way round

Question 6

Cortisol

Answer 6

• Low levels occur due to low autonomic nervous system (ANS) arousal
• People with low levels may seek behaviours that arouse their ANS
• Another hypothesis is that cortisol and feelings of stress mediate the acts people carry out, but that some people produce less cortisol and therefore feel less stressed when committing acts of violence

Question 7

Evidence Which Suggests Other Hormones Are Involved In Aggression

Answer 7

• Care and Mehta’s dual hormone hypothesis explains that high levels of testosterone leads to aggressive behaviour only when levels of cortisol are low – when cortisol is high, testosterones influence on aggression
• Popma et al (2007) studied adolescent males and confirmed support for this hypothesis in relation to direct physical aggression
• We can conclude that the combined activity of testosterone and cortisol may be a better predictor of human aggression than either hormone alone

Question 8

Research With Animals

Answer 8

• Giammanco et al’s (2005) review of studies confirms the role of testosterone
• In male rhesus macaque monkeys, there was an increase in both testosterone levels and aggressive behaviour during the mating season
• In rats, castration of males reduces testosterone and mouse-killing behaviour; injecting female rats with testosterone increase mouse-killing
• These findings show the role of testosterone in a range of animal studies

Question 9

Mixed Evidence Of The Link Between Testosterone & Aggression

Answer 9

• Carré and Mehta’s (2011) dual-hormone hypothesis (high levels of testosterone lead to aggressive behaviour but only when cortisol (hormone that plays a role in the body’s response to chronic stress) levels are low – when cortisol is high, testosterone’s influence on aggression is blocked) can be argued when considering that the combined activity of testosterone and cortisol may be a better predictor than either hormone alone