Testosterone - The Aggressive Hormone?

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Testestorone - The Aggressive Hormone?

• Rats are more aggressive when exposed to testosterone prenatally
• Rats will bite and attack more
• When you castrate male rates the aggression is reduced
• Castrated males lose social dominance (Albert et al., 1986)
• There is also a link between testosterone and aggression in primates (Higley et al., 1966)

Testosterone and Criminal Males (Dabbs et al., 1995)

• Aim: Is testosterone related to the type of violent crimes males commit?
• Method: Measured testosterone in the saliva of 692 male prisoners
  
  • Looked at the criminal records of the prisoners for violent and non-violent crimes
• Results: Found that testosterone levels predicted violent crimes like homicide and rape
• Conclusion: Testosterone levels may affect the types of violent crimes criminals commit
• Evaluation: What about testosterone and violent crimes in females?
  
  • What about effects of environment like upbringing by parents?
  • There is a confounding variable of motivation for committing crimes: senseless violence or acts of vengeance. It is arguably more horrific if someone goes around murdering for fun rather than to right a wrong they feel was done to them
  • This study had a huge sample size which is a strength
  • It is a correlational study and therefore cannot imply causation

Testosterone and Criminal Females (Dabbs and Hargrove, 1997)

• Aim: Is testosterone related to the type of violent crimes females commit and their behavior in prison?
• Method: Measured testosterone in the saliva of 87 female prisoners
  
  • Looked at the criminal records of the prisoners for violent and non-violent crimes
  • Added an extra category of defensive violent which they defined as females being violent towards a perpetrator had abused them in the past
• Results: Found that testosterone levels predicted violent crimes
  
  • Found that testosterone levels were related to their aggressive behavior in prison
• Conclusion: Testosterone levels may affect the violent behavior in and out of prison
• Evaluation: Considering females is a strength
  
  • What about effects of environment like upbringing by parents?
  • They fixed the confounding variable of motivation for committing crimes by adding the defensive violence category
    
    • Why didn't they use this category for the men in the 1995 study? Possible gender bias

Testosterone and Aggression Evaluation Studies

Testosterone and Wrestlers (Fry et al., 2011)

• Aim: Do testosterone levels change when you win a wrestling match?
• Method: Measure blood in testsoterone of 12 collegiate wrestlers before and after their match
• Results: Testosterone increased for both winners and losers but the winners had higher increases than the losers
• Conclusion: Suggests that winning increases your testosterone more so than losing does
• Evaluation: Is the testosterone related to how aggressive they were? Or is the testosterone only related to winning the match?
  
  • What about females? Only male wrestlers were used
  • This study supports the challenge hypothesis of testosterone which is explained later

Testosterone and Chess Players (Mazur et al., 1992)

• Aim: Do testosterone levels change when you win a chess match?
• Method: Measure testosterone in chess players
• Results: Chess players who won had higher testosterone than players who lost
• Conclusion: Chess is non-violent yet testosterone increased which suggests testosterone may be related to winning and gaining social status rather than just being more aggressive
• Evaluation: What about other non-violent games in other cultures?

Testosterone and Fairness (Eisenegger et al., 2010)

• Folk hypothesis of testosterone is that is it linked to aggression
• Aim: Can testosterone lead to fair behavior? Does the belief in the folk hypothesis affect behavior?
• Method: Human females received either testosterone or a placebo
  
  • They played an ultimatum game where participants had to choose how to divide money
  • The proposer could be fair or unfair (the dependent variable)
• Results: Females who received testosterone made fair offers
  
  • Females who received placebo made unfair offers
  • Females who believed they received testosterone made unfair offers
  • Femals who believed they received placebo made fair offers
• Conclusion: There is a social and biological factor at play in terms of testesterone and fairness
  
  • The biological factor of receiving testosterone increases fairness
  • The social factor of believing the folk hypothesis of testosterone affects fairness

Testosterone Overall Evaluation

• Testosterone has been linked to aggressive behavior in both animals and humans
  
  • Problem of causality in testosterone and aggression studies
  • Does having high testosterone cause you to be violent or does being violent raise your testosterone levels?
• The recent evidence favors a social status function of testosterone related to winning and losing rather than purely aggression