In investigating two groups of incarcerated delinquents, 48 in each group, in two different states, a significant correlation between reading underachievement and aggression for both groups was found. Though IQ scores correlated with reading success in both groups, it will be shown shortly that IQ scores are not reliable predictors for determining if one will be able to learn to read; rather the ability to read will to some extent determine IQ scores. But this study is also remarkable for what it didn't find:

" ... the present study was unsuccessful in attempting to correlate aggression with age, family size, or number of parents present in the home, rural versus urban environment, socio-economic status, minority group membership, religious preference, etc. Only reading failure was found to correlate with aggression in both populations of delinquent boys. It is possible that reading failure is the single most significant factor in those forms of delinquency which can be described as anti-socially aggressive. I am speaking of assault, arson, sadistic acts directed against peers and siblings, major vandalism, etc."

Excerpt from Retarding America: The Imprisonment of Potential, pg. 34