Deficiency and Delinquency: An Interpretation of Mental Testing

by James Burt Miner

While there is always a possibility of finding some other factor closely related to delinquency and independent of capacity, nevertheless we should hardly urge this possibility at the present time as overweighing the accumulation of negative evidence which has been assembled in recent years, especially at the Galton Laboratory. We should remember that many so-called outer influences are, like the temptation to drink, related to the incapacity which precedes the temptations. There is also good reason to suppose that many bad environmental surroundings result from rather than cause deficiency. Even broken homes may be a result of incapacity, to which undoubtedly early death is related. The first essential for social philosophers is to recognize that so-called environmental factors may have their corresponding inborn correlates. This is almost invariable with home conditions. The problem is to weigh the relative importance of these outer and inner factors on the same individuals.

(c) Weighing heredity against environment.

Both subjective and objective methods have been used in trying to determine whether heredity or environment has the most influence upon criminality. The earlier and subjective method is one for which Gruhle is perhaps the leading advocate. By this method an expert with wide experience judges the relative effect of inner and outer causes of delinquency in particular cases. In his study of 105 minor delinquents in a German industrial school Gruhle, after a thorough and systematic clinical and sociological study of each person, gave his judgment whether heredity or environment was the main cause of delinquency in the case. In his summary he concluded that in 9 cases the fundamental cause was found in the environment, in 8 cases in environment plus a subordinate influence of heredity, in 41 environment and heredity were balanced, in 20 cases heredity was the main influence but environment was a subordinate factor and in 21 heredity was considered the causal factor. This shows that, when each case was estimated separately, in his opinion heredity on the whole turned out to be more important than environment for this group. By the same subjective method Gruhle weighs the influence of family taints such as mental abnormalities, deficiency, and drunkenness as against the hereditary influence in crime, and comes to the surprising result that in 9 cases where both parents were abnormal mentally or drunken in only two cases was heredity the predominant cause of the delinquency, while in 7 cases where neither parent showed these taints the delinquency was invariably explained by heredity. The group whose delinquencies were in his opinion mainly due to heredity showed, curiously enough, less family taints from nearly every point of view. He concludes:

“The knowledge that so many of the criminal youths are abnormal is indeed very significant for the therapeutic treatment of the social offenders, for the choice of the ways which should be used to improve the youths; but this knowledge has no significance for establishing the causes of delinquency.... The abnormal parents really have more children who are abnormal and under the average in capacity, but their children are actually more seldom delinquent because of the natural tendencies than the children of normal parents” ([121]).

Healy has followed a similar plan in subjectively weighing the influence of various factors as causes of the delinquency of 823 recidivists before the Psychopathic Institute at the Chicago Juvenile Court. Although he does not directly estimate hereditary and environmental factors as such, his summary of these estimates of separate cases shows the main cause of delinquency in 455 of these cases to be some form of mental abnormality or peculiarity. Abnormal physical conditions, including excessive sex development accounted for 40 more. His other causes, which embraced only 26% of the cases, might possibly be regarded as directly environmental. They included defective home conditions, including alcoholism, bad companions, mental conflicts, improper sex experience and habits, etc.

Thus we find that the two most important expert estimates of individual cases after exhaustive study apparently agree in placing the main causal influence on factors which are predominately inner rather than outer. The most serious objection to this method of approaching the problem is that we have no way of determining how far such a result is the effect of the expert's unintentional bias. Gruhle's analysis of his delinquent group, however, raises very clearly the question whether the total influence of heredity may not be markedly greater in the production of delinquency than merely the heredity influence through mental deficiency and abnormalities in the families.

A better method of evaluating the relative influence of heredity and environment would avoid the danger of subjective bias by studying objectively measured factors. With either the subjective or objective method correlation affords a better way of statistically handling the results. The best approach to an objective study of the inner and outer causes of delinquency by the correlation methods is furnished by Goring. The ingenuity of the biometrical procedure in applying correlation to resolving this perennial question of heredity and environment must be recognized by all who take the time to understand its methods. We can only briefly consider the results of Goring's chapter on “The Relative Influence of 'Inheritance' and 'Contagion' upon the Occurrence of Crime and the Production of Criminals.”

This work conclusively demonstrates that crime runs in families. The probable value of the correlation between conviction for crime on the part of the father and son was found to be .60, while the correlation between mother and son was only slightly less. The tendency to resemble brothers in criminality was shown by the probable fraternal correlations of .45. Whether this family resemblance is mainly through nature or nurture is the problem.

In analyzing the influence of the home he uses partial correlation and finds that the correlation between age at first conviction and the number of convictions for a constant period of time after the first conviction is -.243. “From the value and sign of this coefficient, we see that the earlier in life a child commits a criminal offence, and is consequently removed from his home, the worse criminal does he become; and, accordingly, we conclude that criminal proclivities are more bred in the home than inoculated there” (119, p. 368). This argues against the predominant influence of the home training or example as explaining family resemblance in criminality. Nevertheless, it would seem that the result might also be interpreted as meaning that the contact with other delinquents and official discipline outside the home at a more impressionable age notably increases the tendency to recidivism.

Besides the argument as to the earlier removal from home, we have a test of the question whether those kinds of crime that are most influenced by contagion show closer correlation within the family. His statement of the results is as follows: