Normal human psychology has tended more and more in recent years to recognize human behavior as its appropriate subject of study. Students of animal psychology had perforce to deal with behavior, since the only way in which we can get at the animal mind is by the observation of animal behavior. In the course of this study they found that it was extremely difficult, if not impossible, to infer from an animal's actions what he might perhaps be thinking or feeling under a given set of circumstances. The important question is: What does he do? Students of human psychology have been coming, many of them, to much the same standpoint. The human being is a constantly active unit. He has certain regular ways of acting under given circumstances, and in certain ascertainable ways his behavior can be modified. As far as other people are concerned he just is the sum total of his activities. What we are is what we do.

It is necessary to distinguish between such an activity as the functioning of the gland and such another one as carrying on a conversation. The functioning of a gland is just a part process in a larger whole. It is a part of the individual acting. In the case of the conversation the individual is acting as a unit. All those cases in which a human being acts as a whole, responding as a unit to a situation, are designated by the general term human behavior.

A person's behavior, then, is everything that he as an individual does. What he does is determined partly by heredity and partly by environment. At birth the human infant exhibits certain regular ways of acting which it could not have learned, and later on in life other ways of acting, equally unlearned, make their appearance. These are called instincts, and they are inherited. These instinctive ways of acting may be, and normally are, modified to a greater or less degree by the influence of the environment, an influence which in most cases includes education as one of its most important components.

The instincts are changed to such an extent by experience that in the human adult it is always very difficult, if not impossible to determine how much of his behavior is instinctive and how much determined by experience.

It is normal for the human being to live as a member of a group. Most of the instincts, to be sure, are of a self‐seeking character, and the younger the child the more notoriously self‐centered he is. For the most part he has to learn to be a social being with a regard for the rights of others, but even some of the instincts are of a social sort, and these, where they are strong, naturally facilitate greatly the process of learning how to get along with others.

Everyone is in one way or another a student of behavior. This is indicated by the existence and more or less common use of such words as impulsive, affectionate, stupid, reckless, mean, persevering. These words indicate human ways of acting which we have all observed and are able to recognize. Some individuals become very adept in the observation and interpretation of behavior in others. Their ability is always of value to them, and frequently they make it of great value to society. It is in no way belittling their accomplishments to indicate that scientific methods will in the end accomplish more.

Science leaves as little as possible to personal judgment; by its systematic procedure it achieves a high degree of accuracy; and its results, once obtained, are in a form which makes them universally available. Suppose that we are dealing with a child that is unable to get along in school, and are called upon to face the question of whether it has sufficient intelligence to do the work required of it. We may look the child over, talk to it, ask it questions, and then on the basis of the impression the child has made conclude whether or not it has the requisite intellectual qualities. Anyone who has had experience with mental tests knows how untrustworthy such personal impressions are. If the child has bright eyes, a ready sympathetic smile, and a sprightly way of talking, and all of these characteristics are sometimes found in the feeble‐minded ‐‐ its intelligence is likely to be overestimated; and similarly because of the presence or lack of other characteristic errors equally great may be made in the opposite direction. However, supposing that our estimate is substantially correct, how are we going to express it? Such terms as 'dull' or 'bright'; or even the more specific term 'moderately dull' having little meaning for another person who may not know what our standard of dullness is. Never‐the‐less let us suppose that our impression is correct and that we are able to say, “This child is so dull that it can't do work higher than that of the third grade," and let us further suppose that we can judge children in this way with a high degree of accuracy. We then have an art of great value, but one which would die with us unless we could reduce it to a science and thus make it available to others.

Now consider the method which science has worked out to deal with cases like the one just considered. We give the child an intelligence test. This is really just taking a sample of the child's behavior. We put the child into a number of standard situations by asking it questions and giving it tasks or problems, and then we note just what the child does under the standard conditions. Our personal judgment does not enter. Then, when the tests have been given and the results added up, we have an exact expression of the child's intelligence in terms of years of mental age, or in the Intelligence Quotient, which is the child's mental age divided by his chronological age. This definitely places the child. We know exactly how he stands in the matter of intelligence as compared with normal children. Of course in any individual case other factors in the child's make‐up besides those measured by the intelligence test may be significant in determining school success or failure. Hence it is necessary that in cases of this sort the result of the intelligence test should be interpreted by a specialist of thorough training and experience who can take the other non‐intellectual factors into account. As yet we have no standard tests for these latter factors, though a promising beginning toward the development of such tests has been made.

We can understand the anomalous, the unusual, the abnormal, only by comparing it with the normal. The establishment of norms, therefore, is one of the first and most important steps in the study of anything in which there is the possibility of a wide range of variation. In the field of intelligence this has been accomplished. We have a way of measuring intelligence and an established norm with which to compare the various grades of mental deficiency or of mental superiority. In the case of intelligence, as in that of other human characteristics, it is found that the majority of people fall closely around the normal. As we go down to the lower grades of intelligence the farther we go from the normal the smaller the number of cases we find. Similarly, as we go up from the normal we find the number of cases decreasing in the same way. Just as we have a relatively small group of individuals very defective in intelligence, so also just as far on the other side of the normal we have a small group of individuals of very superior intelligence. The former are mainly the individuals who present the Social problem of feeble‐mindedness, the latter mainly the most valuable members of society. This does not, of course, hold invariably; for an individual who rates low in intelligence may, because of the possession of desirable traits, be a valuable member of society, while an individual who rates as very superior in intelligence may have undesirable traits which make him a menace to society. Such cases, however, are the exception rather than the rule.

I shall consider briefly three groups of individuals who by reason of their anomalous behavior constitute social problems. The groups are those of the feeble‐minded, the insane and the delinquent. Feeble‐mindedness has already been spoken of, and the use of intelligence tests in its diagnosis indicated. For the more serious cases the states have established institutions where the inmates are given custodial care and, through training and supervision suited to their level of intelligence, are enabled to contribute something to their own support. However significant and important the work of the institution is, I believe that a great deal of work is needed outside its walls. Consider, for example, the case of the feeble‐minded child in school ‐‐ a case not so obviously defective that he is readily identified. He enters school at about the age that other children do but does not progress. At first his defect is not noticed. Then, when he has had to repeat several grades, he is regarded as “ backward," and it may be that his mental defect is not recognized for some years if at all. There is the expense of education which has done no good, and the inevitable bad effect of the presence of the defective upon the work of the other children. If such a child could be examined by a specialist soon after the beginning of his school career his defect could be determined at the start and the bad result of his continuance in school avoided. Teachers can be taught to recognize mental defect well enough to pick out suspicious cases for examination by a specialist. The earlier in life, those who are in need of special treatment are recognized and taken care of the better.

In the field of psycho‐pathology systematic behavior study has been carried on for some time. Finding a bodily interpretation of insanity inadequate, students in this field classified their cases according to the forms of behavior they exhibited. Certain fairly definite forms of diseased personality appeared and it then became possible to work out the particular type of treatment best suited to the particular form of abnormality. Intelligence tests are of assistance in the diagnosis of some forms of insanity, but at best they are only a contributing factor. The specialist has to rely upon his personal judgment more in the case of insanity than in the case of feeble‐mindedness. Borderline cases of insanity outside of institutions, and, indeed, some cases beyond the border sometimes go unrecognized. Many of them, as also many cases of feeble‐minded persons, are taken care of by relatives and friends. As long as they remain under this care and in the environment to which they are accustomed, they may get on quite well. But if for any reason the oversight is removed or the environment changed the abnormal or the subnormal individual is likely to get into serious trouble. The conditions resulting from the war brought out many cases of this kind.

Just as the earlier students of insanity sought a bodily explanation for it, so the earlier criminologists looked for a bodily explanation for criminality. It was thought that criminals must have certain physical stigmata which could be determined by measurement. A large mass of data was assembled, but the hoped‐for explanations did not result. Physically criminals were found to be little if any different from honest men. So criminologists are now turning their attention to behavior study. Criminals are being sorted into classes according to their personality characteristics. In this process psychological tests play a part. It is recognized that there are a number of different types of criminal, and that treatment which may produce good results with one type may be the worst possible form for a different type. Here, as in the field of feeble‐mindedness the value of handling the case while it is still young has been recognized. This is evidenced by the establishment of juvenile courts, and in connection with them special institutions for dealing with youthful offenders. Without doubt methods will eventually be evolved which will make it possible to identify potential criminals in their earlier years and to control and correct their behavior as they grow older.

In closing I should like to emphasize a phase of the whole question that is, it seems to me, of cardinal importance. It has to do with the borderline case of anomalous behavior of what ever sort. There is no sharp dividing line between the normal and the abnormal. Normal intelligence, for example, shades imperceptibly through ever increasing degrees of dullness into feeblemindedness. The feeble‐minded are not a qualitatively different species to be set apart and contrasted with normal individuals. They are simply the members of the community who are least heavily endowed with intelligence. Indeed the worst cases of feeble‐mindedness are not the most serious social problem at the present time. They are easily recognized and readily dealt with by the method of custodial care. The individuals who present the more difficult problems are those who occupy the borderland. Their defect readily passes unnoticed and they are relatively more numerous than the more defective cases. A layman can usually pick out an idiot or an imbecile. It often takes a specialist of wide experience and the application of mental tests to identify a moron. And yet these individuals may be potential criminals. A general survey of the younger generation would make possible the registering of borderline cases. These individuals should be regarded as on probation, as individuals whose behavior must be carefully watched and if necessary controlled. The same applies, of course, to borderline cases of other kinds. Society must keep accurate account of its human liabilities.

Dr. C. F. Dalton spoke of the dangers involved when, as is frequently the case, subnormal children of fourteen or fifteen years of age associate in classes and on playgrounds with normal youngsters of seven or eight. This association of defective adolescents with younger children of impressionable age permits communication of evil suggestions, bad habits, etc. Possibly the use of Binet tests in the schools would help to weed out those children who may be a source of degrading suggestions.

Dr. Allen spoke of the value of industrial training for sub‐normal children.

Prof. Metcalf spoke of mental surveys which have been carried out in many states. Such a survey defines the problem to be attacked as it discovers the extent of feeble mindedness and the nature of the cases existing.