CHAPTER 14. 



RELATION OF INTELLIGENCE EATINGS TO AGE. 



The dependence of intelligence upon age of adults is a theoretical problem of great interest 

 upon which, however, the results of psychological examining in the Army can throw little 

 light. It is possible to draw up tables of intelligence ratings and age as reported on the 

 examination blank, to compute the regressions, and thus to determine the relation between 

 age of officers or of men in the Army and their intelligence; but with the relationship once 

 determined there is still no way of saying to what extent it reflects a fundamental dependence 

 of intelligence upon age or to what extent it may be caused by the selective processes always 

 at work in separating the Army from the total population of the country. If among the older 

 men only the more intelligent sought to be officers or were so well established in life that they 

 could afford to be officers, or if, on the contrary, among the older men only the poorer 

 professional men could leave their businesses to enter the Army or were industrially unessential 

 so that they were forced into the Army, then we should find a very positive relation of the one 

 sort or the other between intelligence and age in the Army — a relation which would arise 

 entirely as a result of selection in the Army and be utterly factitious as an indicator of a 

 dependence of intelligence on adult age in general. Similar selective factors might work 

 equally well in the case of drafted men. At best, then, we can not expect much from a study 

 of age and intelligence ratings in military records, and for this reason, under the pressure of 

 time and insufficient clerical personnel, the Hollerith sortings between age and intelligence 

 ratings of the white and the negro drafts as originally planned for the principal sample were 

 abandoned. The sortings were carried out for officers because the greater range of ages made 

 some sort of a positive relationship, whatever its interpretation, likely. 



These figures are avadable and to them may be added the results of studies on either 

 examination a or alpha from six camps. The results are for the most part self-consistent 

 in that they show a slight but persistent tendency for decrease of mean intelligence rating 

 with age — at least in the higher age groups which range above the upper limit of the draft. 

 They are presented in order that the facts may be at hand. In view of our ignorance of the 

 operation of the selective forces in the Army it is unsafe for us to assert that the apparent 

 relation is not spurious. The most reasonable surmise is that older officers are selected more 

 on the basis of their specific experience and training, professional or military, and less on 

 native intelligence than are younger officers who have as yet little valuable experience. Given 

 time for it to accrue, it may be that experience offsets intelligence in the requisites for an 

 Army officer. The Medical Corps, for example, is distinctly a professional corps and its officers 

 are consequently on the average much older than any other group of officers (see below). 

 The low level of the intelligence ratings in this corps may be in part due to the selection of 

 officers on the basis of professional experience and availibility rather than on general mental 

 ability. 1 



It has been argued that older officers are at an unfair disadvantage in the alpha examina- 

 tion in that they have the kind of intelligence that works surely but slowly — that alpha is a 

 "speed test." 2 It was never clear in practice, however, that the older officers actually did 

 do more poorly than the younger; it appeared as if it might be that the older officers who 

 made poor ratings simply attracted to themselves more attention than did the young officers 



1 But it is not probable that the intelligence level of the Medical Department is entirely to be explained in this manner. The younger officers 

 of the Dental and Veterinary Corps score lower on tho average than the officers of the Medical Corps. 



2 Seo the discussion of alpha as a "speed test" in the chapter on the Effect of Doubling the Time Limits in the Alpha and Beta Examina- 

 tions, chapter, 9, Part II, pages 415 to 420. 



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