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

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