Biological and environmental factors

There had been little contact between criminological thinking and psychology until psychologists started to deal with the computation of "mental age" and of the I.Q. of delinquents and criminals. A number of psychologists applied their new and not yet sufficiently founded theories to the population of prisons and reformatories and thought that, with the discovery of a high correlation between feeble-mindedness and criminality, they had found the key for the definite solution of the problem of crime causation. The main error of these students of crime was made in the psychological field. Their criteria of "normal intelligence" were arbitrary because they were not based upon examination of a fair sample of the population.

 

The assumption that low intelligence was the main cause for crime has proven untenable. A number of investigations have shown that the correlation between feeble-mindedness and crime is so low that no significant inferences can be drawn. Considering the effort which has been put into collecting evidence for the assumption that criminality is mainly due to low mentality, we recognize one of the ideas which frequently has led students of crime astray. The law-abiding person, whether he be a social scientist or not, has had a desire to prove that the criminal is "abnormal" in one way or another. There has been a general, probably unconscious fear to realize that the criminal is as much a human being as the righteous citizen.