A reader sent me a link to an MSNBC article about how a variant of the MAOA gene is correlated with aggressive and violent behavior. This proves that at least one significant aspect of personality varies between individuals because of genetic predisposition.
Searching the internet, I discovered a study from 2006 explaining that the Maori, the indigenous people of New Zealand, are approximately twice as likely as whites to have the bad variant of this gene. Thus we see that one racial group is, on average, genetically predisposed to anti-social behavior compared to another racial group.
HBD has been proven.
If you want to read about this topic in more detail, here's a link to a very big PDF file of the August 2008 issue of the American Sociological Review. It seems to me that the authors of that article are in possession of the information of whether or not the bad variant of that gene occurs more frequently in the American black population, but they declined to discuss that topic. I wonder why?
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As Peter pointed out in a comment below, according to Wikipedia, “Although Māori make up only 14% of the population [of New Zealand], they make up almost 50% of the total prison-population.”