More on the Biology of Crime

This subject is absolutely deadly for progressives because there is a fear that an examination into the biology of crime will tend to focus on race. As is, in the US, Blacks, Hispanics, Amerindians and Polynesians have crime rates, 8, 3, 2 and 2 times higher than Whites, respectively. Asians have crime rates 5 times lower than Whites.

Leaving aside race for a moment, it is reasonable to pry into the extra-racial aspects of crime. For the moment, let us look at testosterone and MAO-A levels.

MAO-A inhibits the production of catecholamines, in particular serotonin. Persons low in MAO-A tend to be low in serotonin.

Persons low in serotonin have elevated rates of impulsive violent behavior, including homicidal and suicidal attempts and successes. These studies have been done on successful suicides and impulsively violent criminals behind bars. Serotonin is an inhibitory chemical. It follows that low levels of an inhibitory chemical would make a person less inhibited in some ways.

A UK study on abused children found that those who had good MAO-A levels did not develop antisocial behavioral problems. Those who had low MAO-A levels did become antisocial. In this way, chemical levels in the brain interacted with negative environmental effects to either promote or inhibit antisocial behavior. It's clear that abuse alone is not enough to cause antisocial behavior de novo.

In Aggression: The Testosterone-Serotonin Link , Berger et al attempted to synthesize studies showing links between low serotonin and high testosterone to better explain the enigma of criminal behavior. With regard to testosterone, they noted that results indicated a positive correlation in boys between testosterone levels and serious aggression in social situations, but no correlation with playful aggression.

This is interesting. Boys with normative testosterone can be quite aggressive in play, but they are able to turn it off and keep from going over the edge into actual serious aggression. High-testosterone boys were aggressive in both play and in serious aggression.

A study of 4,462 men revealed that the overall picture among the high-testosterone men is one of delinquency, substance abuse and a tendency toward excess aggressive behavior. This is the classic picture of the teenage delinquent, gang member, etc.

These men have more trouble with people like teachers while they are growing up, have more sexual partners, are more likely to show disciplinary problems during their military service and to have used "hard'' drugs, particularly if they had a poor education and low incomes.

As we can see, poor educational outcome and low income serve as additive effects for high-testosterone men who display antisocial or sociopathic tendencies.

Measurements of testosterone saliva levels in 692 adult male prisoners showed that inmates who committed violent or sexual crimes had higher testosterone levels than inmates who were incarcerated for property crimes or drug abuse. Therefore, theft and drug abuse is not necessarily related to high testosterone. Anyone can be a thief or a doper, but not anyone can be a rapist or commit violent assaults.

This study also showed that inmates with higher testosterone levels violated more prison rules, especially those involving overt confrontation.

When salivary testosterone levels of young adult delinquents were compared with levels of a group of college students, matched for age, gender and race, the delinquent subjects had higher testosterone levels than the student controls, a finding that was true for both male and female subjects. It is interesting that even female young adult delinquents tend to have higher testosterone levels.

It can thus be concluded that high testosterone levels play a role in some criminal behavior.

In a previous post, I suggested that interventions to lower testosterone may be one avenue with which to attack testosterone-driven crime and antisocial behaviors.

These interventions would involve Black females taking a drug to lower the testosterone of their fetus 20%. Or giving the same drug to their young sons with the same effect. Or, offering it to young Black males who display repeated antisocial behavior, have gotten into serious trouble due to this behavior, want to change, but can't seem to. All of these interventions would have to be strictly voluntary.

Commenters have noted with horror the possibility of messing with the sex drives of Black males, but a 20% reduction would lower Black testosterone down only to the White male level. White males seem to be awfully horny last time I checked.

Now for the racial angle. Yes, Blacks do have higher testosterone than Whites. And Asians have the lowest levels of all. Precisely as we might expect from the crime findings.

Hmmm.

References

Birger M, Swartz M, Cohen D, Alesh Y, Grishpan C, Kotelr M. 2003. Aggression: the Testosterone-Serotonin Link. Israel Med Assoc J 5: 653-658.