Testosterone, Aggression, and Violent Crime

Testosterone, Aggression, and Violent Crime
Michael Bell, B.S.
University of Pittsburgh

Is it purely testosterone that causes aggression or is it a person’s background, genetic predisposition, or learned behaviors that cause the aggression?  
I looked at two different studies, one done on male inmates and one done on female inmates, and both studies showed a definite link between testosterone levels and violence.
In a study done in 1987, free testosterone was measured in the saliva of 89 male prison inmates. Inmates with higher testosterone concentrations had more often been convicted of violent crimes. The relationship between testosterone and violence was most obvious at the extremes of the testosterone distribution, where 9 out of 11 inmates with the lowest testosterone concentrations had committed nonviolent crimes, and 10 out of 11 inmates with the highest testosterone concentrations had committed violent crimes. Among the inmates convicted of nonviolent crimes, those higher in testosterone received longer times to serve before parole and longer punishments for disciplinary infractions in prison. In the housing unit where peer ratings were most reliable, inmates rated as tougher by their peers were higher in testosterone (Dabs, H.M. et al, 1987).
In another study done at Georgia State University, with the objective of determining how testosterone levels, both alone and interacting with age, were correlated with criminal behavior and institutional behavior among female inmates, a similar result was found to the male study. 
Eighty seven female inmates had their saliva sampled to test for levels of testosterone and their criminal behavior was scored from court records.  Their behavior while incarcerated was scored from prison records and interviews with staff members.
The results showed a definite causal relationship between testosterone levels in women and violence, both in committing a violent crime and also continued violent behavior while imprisoned.  The study also showed a causal relationship between age, reduction in testosterone levels, and reduction in violent behavior.  Older women showed lower serum levels of testosterone, and also exhibited less violent behavior.  Younger women showed higher serum levels, committed more violent crimes, and exhibited violent behavior while incarcerated (Dabbs, H. M. et al, 1997).
Socialization theories suggest that violence is not only hormonal but also a learned behavior. Children coming from an “inadequate” background learn violent behavior, while children from an “adequate” environment learn prosocial behavior.  Prosocial behavior is defined as “helping” behavior versus aggressive behavior.  A third study done by Cambridge, claims that children who don’t learn to suppress innate violent behaviors are excluded by peers and are rewarded for positive behavior.  The study postulates that violence may be genetically predisposed, but it is developed during childhood from environmental factors (Cambridge, 2007).

Works Cited
"Aggressive and Prosocial Behavior." Cambridge Encyclopedia of Child Development. Cambridge: Cambridge UP, 2005. Credo Reference. 20 Sept. 2007.
Dabbs JM Jr, Frady RL, Carr TS, Besch NF. Saliva testosterone and criminal violence in young adult prison inmates. Psychosom Med. 1987 Mar-Apr;49(2):174-82.
Dabbs JM Jr, Hargrove MF., Age, testosterone, and behavior among female prison inmates. Psychosom Med. 1997 Sep-Oct;59(5):477-80.

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