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Christopher D. Green
York University, Toronto, Ontario
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CHAPTER 7: THE METHODS OF EXPERIMENTAL PSYCHOLOGY
We now see clearly the psychotechnical problem. We have to analyze definite economic tasks with reference to the mental qualities which are necessary or desirable for them, and we have to find methods by which these mental qualities can be tested. We must, indeed, insist on it that the interests of commerce and industry can be helped only when both sides, the vocational demands and the personal function, are examined with equal scientific thoroughness. One aspect alone is unsatisfactory. It would of course be possible to confine the examination to the individual mental traits, and then theoretically to determine for which economic tasks the presence of these qualities would be useful and for which tasks their absence or their deficiency would be fatal. Common sense may be sufficient to lead us a few steps in that direction. For instance, if we find by psychological examination that an individual is color-blind for red and green sensations, we may at once conclude, without any real psychological analysis of the vocations, that he would be unfit [p. 58] for the railroad service or the naval service, in which red and green signals are of importance. We may also decide at once that such a boy would be useless for all artistic work in which the nuances of colors are of consequence, or as a laborer in certain departments of a dyeing establishment, and that such a color-blind girl, would not do at a dressmaker's or in a millinery store. But if we come to the question whether such a color-blind individual may enter into the business of gardening, in spite of the inability to distinguish the strawberries in the bed or the red flowers among the green leaves, the first necessity, after all, would be to find out how far the particular demands of this vocation make the ability to discriminate color a prerequisite, and how far psychical substitutions, such as a recognition of the forms and of differences in the light intensity, may be sufficient for the practical task. Moreover, where not merely such mental defects, but more subtly shaded variations within normal limits are involved, it would be superficial, if only the mental states were examined and not at the same time the mental requirements of the vocations themselves. The vocation should rather remain the starting-point. We must at first find out what demands on the mental system are made by it, and we must grade these demands in order to recognize [p. 59] the more or less important ones, and, especially for the important ones, we must then seek exact standards with experimental methods.
Such an experimental investigation may proceed according to either of two different principles. One way is to take the mental process which is demanded by the industrial work as an undivided whole. In this case we have to construct experimental conditions under which this total activity can be performed in a gradual, measurable way. The psychical part of the vocational work thus becomes schematized, and is simply rendered experimentally on a reduced scale. The other way is to resolve the mental process into its components and to test every single elementary function in its isolated form. In this latter case the examination has the advantage of having at its disposal all the familiar methods of experimental psychology, while in the first case for every special vocational situation perfectly new experimental tests must be devised.
Whether the one or the other method is to be preferred must depend upon the nature of the particular commercial or industrial calling, and accordingly presupposes a careful analysis of the special economical processes. It is, indeed, easy to recognize that in certain industrial activities re series of psychical functions is in question which [p. 60] all lie side by side and which do not fuse into one united total process, however much they may influence one another. But for many industrial tasks just this unity is the essential condition. The testing of the mental elements would be in such cases as insufficient as if we were to test a machine with reference to its parts only and not with reference to its total united performance. Even in this latter case this unified function does not represent the total personality: it is always merely a segment of the whole mental life. We may examine with psychological methods, for instance, the fitness of an employee for a technical vocation and may test the particular complex unified combination of attention, imagination and intelligence, will and memory, which is essential for that special kind of labor. We may be able to reconstruct the conditions so completely that we would feel justified in predicting whether the individual can fulfill that technical task or not; and yet we may disregard entirely the question whether that man is honest or dishonest, whether he is pacific or quarrelsome; in short, whether his mental disposition makes him a desirable member of that industrial concern under other aspects.
We best recognize the significance of these various methods by selecting a few concrete cases as illustrations and analzying them in detail. But a [p. 61] word of warning may be given beforehand so as to avoid misunderstandings. These examples do not stand here as reports of completed investigations, the results of which ought to be accepted as conclusive parts of the new psychotechnical science; they are not presented as if the results were to be recommended like a well-tested machine for practical purposes. Such really completed investigations do not as yet exist in this held. All that can be offered is modest pioneer work, and just these inquiries into the mental qualities and their relations to the industrial vocations have attracted my attention only very recently, and therefore certainly still demand long continuations of the experiments in every direction. But we may hope for satisfactory results the earlier, the more coöperators are entering the field, and the more such researches are started in other places and in other institutions. I therefore offer these early reports at the first stage of my research merely as stimulations, so as to demonstrate the possibilities.
As an illustration of the method of examining the mental process as a whole, I propose to discuss the case of the motormen in the electric railways. As an illustration of the other type, namely, of analyzing the activity and testing the elementary functions, I shall discuss the case of the employees [p .62] in the telephone service. I select these two functions, as both play a practically important rôle in the technique of modern economic life and as in both occupations very large numbers of individuals are engaged in the work.