Batrinos (2012) is a paper titled Testosterone and Aggressive Behavior in Man. Section 2 reviews studies on prisoners. Small ns, no controls, prison isn’t a natural environment. Similar data was reported, but it has the same problems as above. Studies of sexual offenders are contradictory, with blood T not being associated, then being associated with aggression. An investigation of veterans showed T to raise aggression, again, non-representative sample (and you also have to think of PTSD and other illnesses). Then the money quote:
It is of interest, however, that supraphysiological doses of testosterone in the order of 200 mg weekly (20), or even 600 mg weekly (21), which were administered to normal men had no effect on their aggression or anger levels.
Dominance is related to testosterone increases, and dominance can lead to aggressive behavior then to violent acts, but this is not always true. Mazur and Booth’s (1997) reciprocal model shows a feedback loop on dominance and testosterone:
Ehrenkranz et al. (1974) showed that socially dominant but unaggressive prisoners had relatively high T, not significantly different from the T levels of aggressive prisoners (who may have been dominant too). Nearly all primate studies that have been interpreted as linking T to aggression (Dixson 1980) may as easily be interpreted as liking T with dominance (Mazur 1976). Recent reviewers have questioned whether, among humans, T is related to aggressiveness per se (Archer 1991; Albert et al. 1994).
Heightened testosterone is not a direct cause of male violence.
(Much more on this paper soon.)
Small studies have shown that T increases during sports (duh because it’s competition) and that watching your favorite sports team win a game increases T (has been replicated).
Batrinos then cites a study talking about circadian rhythm and testosterone/aggression here:
Interestingly enough, Brown et al (2007) lends credence to my hypothesis that I have discussed in the past. Testosterone decreases at 8pm (most crime is comitted at 10 pm for adults) with increases in testosterone at night:
It is not surprising that T levels at 2000 h and 0800 h would be important for TS-IAB relationships because the 2000 h and 0800 h values represent the evening nadir and morning zenith.
But most crime is not comitted in the morning, for both adults and children (as seen below):
Now, anyone who has read my article on why testosterone doesn’t cause crime knows where I’m going with this:
Look at the times most crimes are committed then think about when T levels are highest (8 am).
This does seem to show a relationship with when most crimes are comitted, a sharp decrease in crime occurs as testosterone levels hit their highest in the day, which is evidence against the testosterone-causes-crime hypothesis.
In regard to the crime chart from the OJJDP, they write:
- In general, the number of violent crimes committed by adults increases hourly from 6 a.m. through the afternoon and evening hours, peaks at 10 p.m., and then drops to a low point at 6 a.m. In contrast, violent crimes by juveniles peak in the afternoon between 3 p.m. and 4 p.m., the hour at the end of the school day.
Using what I gave, what do you draw from the line graph? It’s clear that, since testosterone is highest in the morning aand at its lowest at 8 pm (when most violent crime is being comitted) that testosterone is not directly related to crime, since, as evidenced by Brown et al (2007), testosterone levels are lowest at 8 am with a sharp rise as the night/ morning progresses. Looking at their testosterone chart for the hours between 8 pm and 8 am, testosterone did increase at 8pm and into the night. However, as testosterone levels continued increasing into the night, crime does not linearly increase with the rise in testosterone (see fig. 3 in Brown et al, 2007).
Now, finally, in regards to the claim about “locally produced testosterone”, it is true that the brain can produce testosterone de novo from cholesterol; but wait! Luteinizing hormone signaling in the neurons promotes the secretion and production of steroids (Liu et al, 2007), along with the de novo production of testosterone through cholesterol (literally the only way testosterone can be produced).
Good paper, shaky claims (the prisoner claims suck, circadian rhythm claims suck). The only novel thing in this paper is saying how the brain can produce testosterone de novo from cholesterol (though luteinizing hormones are still involved, see above cite). Injecting a man with supraphysiologic doses of testosterone does not increase aggression nor anger levels. It’s definitive that testosterone does not directly cause crime, as evidenced by the low correlation between testosterone and aggression. Numerous other studies (which I have reviewed in the past), however, show that aggression precedes the testosterone increase which is only seen in certain social situations. These specific situations, by themselves, drive the production of the hormone.