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Hormones in Context:
Testosterone and Aggression - Crimes of violence


Among tests with humans, several groups of normal men were given psychological tests to measure hostile or aggressive feelings. The possible link with aggression is defined in various ways, in different studies, from verbal abuse upwards.

In one test, there was correlation between the younger men but not the older ones. In another group there was no correlation at all. In another study, measurements taken over two days produced no consistent results.

The biological argument makes much of the fact that many more men than women are convicted of violent crimes. Therefore, other studies have focused on violent male criminals and psychiatric patients.

It has been found that men convicted of violent crimes have higher levels of testosterone than average men with no convictions, and that men convicted of violent crime have higher levels than men convicted of other crimes. However, there was no difference between non-criminals and men with convictions for non-violent crimes.

While there may be a consistent pattern, it does not, in fact, say anything about how it arose. Finding a high correlation between violent men in prison, does not distinguish between cause and effect. Prison, after all, is not the safest place to be, so raised testosterone might have been an effect of being in prison.

It is equally likely that a violent lifestyle leads to high testosterone level. If testosterone has some effect on criminality then reduction should reduce the crime rate. However, when drugs are used to reduce the level in criminals there is little effect on their rate of re-offending. In fact, in a study(1) of men castrated to calm them down, nine out of sixteen died as a result of aggressive encounters. Perhaps the loss of testosterone did not reduce their tendency to fight, but affected their ability to win.

In general the studies on testosterone and human aggression reach the conclusion that testosterone is involved but is not a prime factor. It would appear that humans are continually aggressive if they already have a violent personality, and psychologists differ about the interaction of biology and socialisation on personality. If the evidence is that an aggressive approach to life is learnt, it is assumed that hormone levels are set by an individual's innate biology. Is it possible that a particular hormonal milieu can develop during the plasticity of childhood?

Next Page: Childhood.

Bibliography and good reading.

  1. Fausto Sterling, A., (1992) Myths of Gender, Biological Theories about Women and Men, (p126) New York: Basic Books
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Bland, J.,(2002) About Gender: Testosterone and Aggression - Crimes of violence.
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Web page copyright Derby TV/TS Group. Text copyright Jed Bland.
06.05.98 Last amended 12.03.02