or professional school, whereas D- individuals are rarely able to pass beyond the third or fourth grade of an elementary school, however long they may attend. The methods developed for the classification of personnel under the Adjutant General of the Army and for the solution of special problems are entirely too varied for description here. In the first instance they are primarily adaptations of business methods, many of which were improved and supplemented by the application of psychological knowledge and experience. In the case of special psychological problems it was usually a matter of analyzing the military situation carefully and of drawing upon the resources of psychological laboratories, or more often of psychological skill, for the particular variety of apparatus or technique which promised to solve the problem. Ingenuity was at a premium, but it could not be used successfully until the military situation had been skilfully analyzed and its important factors or requirements brought into clear light. Several psychologists were eminently successful both in analysis and in devising or adapting methods to cover the results of analysis. WITH the preceding chapter on methods as an introduc tion, an attempt will be made in the present chapter to state very briefly what psychology accomplished during the war. It is impossible to give a complete account of the work, but results and practical applications may be sampled in such a way as to give the reader a fair idea of the nature and significance of this new kind of military service. ILLITERATE FIG. 1.-DISTRIBUTION OF INTELLIGENCE RATINGS IN TYPICAL ARMY GROUPS, SHOWING VALUE OF TESTS IN IDENTIFICATION OF OFFICER MATERIAL. GROUP GIVEN beta; otheR GROUPS, ALPHA. Figure 1. Distribution of intelligence grades for typical army groups. The first thing which appeared in the results of the psychological examination of soldiers was remarkable difference in the intelligence of individuals and of army groups. This fact was no surprise to psychologists, but it created a profoundly important impression in the minds of military officers who were relatively unfamiliar with methods and results of mental measurement. The two figures, 1 and 2, will suffice to indicate the extent of these differences. The one of these figures, I represents the distribution of the various grades of intelligence in such important military groups as enlisted men, non-commissioned officers (corporals and sergeants), students in officers' training camps (O. T. C.), and officers. The letter grades, as has already been stated in the previous chapter, designate from A to D degrees of intelligence which range all the way from very superior (A) to very inferior (D-). Commissioned officers of the United States Army,with few exceptions, possess superior or very superior intelligence. A few of the good officers fall in the C+ class and a still smaller number, almost invariably unsatisfactory to the service, possess only average intelligence, designated by the letter C. By contrast with the officers, illiterate enlisted men usually possess inferior intelligence. Many of them are very inferior and relatively few rise above the high average represented by C+. The average literate enlisted man possesses that middle grade ability which is designated by C. Another method of representing differences in intelligence between important military groups is used in Fig. 2. In this case the several grades are thrown into three groups which may be designated conveniently high, medium, and low. It is noteworthy that commissioned officers are found only in the medium and high groups, that students in officers' training camps, who by virtue of this fact are candidates for appointment as officers, occasionally fall in the low intelligence groups. White recruits are rather more frequently found in the low than in the high groups, although the great majority of them are of medium intelligence. Those soldiers who are least satisfactory for military service and most expensive are more often than not found to have low intelligence. The figure in question roughly represents the results for four such groups: disciplinary cases, men ranked by their officers as poorest in their company, men of low military value as judged by their officers, and unteachable men. The results of psychological examination as sampled by these two figures indicate the distribution of intelligence which existed when psychological work was undertaken. The meaning of this distribution is that by various selectional processes, more or less cumbersome, time-consuming, and expensive, highly intelligent men become commissioned officers, somewhat less able A and B D.D-,E C+,C,C- 8819 O.T. S.Students 9240 Sergeants 3393 Corporals 4093 "Ten Best Privates 606 White Recruits Disciplinary Cases "Ten Poorest"Privates "Men of Low Military Value" "Unteachable Men" 255 Camp Hancock Figure 2. The proportions of low, average, and high grade men in typical army groups. men become sergeants or corporals or excellent privates, while the least intelligent of all worry along as poor privates or as relatively unteachable. Army officers to whom such results as these were presented saw the point immediately and, admitting marked differences in intelligence among men, they went right to the practical point by asking the psychologist what relation intelligence has to the ways of using men in the army and to general military value. Luckily it was not difficult to answer this question definitely and satisfactorily and that not by the statement of some psychologist's opinion but by the presentation of results of measurements made in the army itself and exhibited in their relations to the judgments of experienced officers. A number of pictures of these results will enable the reader to grasp quickly the significant points. Figure 5. The relation of intelligence to success and failure in officers' training schools. Figures 5 and 6 indicate the relation of intelligence to success and failure in officers' training camps and in noncommissioned officers' training camps. Again, it should be emphasized that the students in these camps had been admitted prior to psychological examination and practically without reference to their intelligence. The psychological ratings were obtained and subsequently were compared with the records of success and failure in the schools. It is notable that in both types of school, the proportion of failures increases steadily |