One of the many arguments for colorism runs: Darker African-Americans have been found to receive longer prison terms than lighter African Americans. Ergo.. Yes, that’s the argument — with the implicit premise being: And there are no plausible causes, besides anti-dark skin bias, for the correlation between color and length of sentence. Commenting on findings, one science blogger noted:
This proven correlation between skin tone and judicial outcomes doesn’t absolutely prove that skin tone directly causes shorter sentences and earlier release for recent black female prison convicts in North Carolina (“correlation is not the same as causation”). However, it’s hard for me to envision what these intervening factors may be, and there’s clearly a strong link between the two.
And yet new research sheds light on the mechanisms of one probable intervening factor:
Turning to the findings from the IQ Model, three points deserve attention. First, individual-level IQ differences were significantly related to violent misconduct. Inmates with above average IQ scores (relative to other inmates housed in the same facility) were at decreased risk of being involved in a violent incident. A one standard deviation increase in IQ score (as compared to other inmates within the same prison unit) was associated with a ten percent reduction in the odds of committing violent misconduct. The second finding of interest was that the introduction of the IQ variables led to a slight attenuation of the relationship between race/ ethnicity and misconduct. Finally, the average IQ of the prisoners within each of the 30 different prison units was found to have a significant effect on the likelihood of an inmate committing violent misconduct. Simply stated, individuals housed in a unit with a higher average IQ score were significantly less likely to engage in violent misconduct. (Diamond et al., 2012. Individual and group IQ predict inmate violence)
Since the darkest African Americans are only 0.5 SD less intelligent than the lightest, other pathways than color-> IQ-> inmate violence-> increased sentence length must account for some of the 12% of sentencing differences found (as there would only be a 5% difference in immate violence rate, as conditioned by IQ). As IQ has consistently been found to be associated with impulsivity, other pathways may lead from IQ differences to sentence length differences. Alternatively, since in large multicultural samples criminality has been found to be modestly heritable, the causal pathways may be more direct.