The abilities of man : their nature and measurement / by C. Spearman.

  • Charles Spearman
Date:
1927
Catalogue details

Licence: In copyright

Credit: The abilities of man : their nature and measurement / by C. Spearman. Source: Wellcome Collection.

    89/474 page 77
    came into sharp conflict with the most authoritative psy¬ chology then prevailing, the latter being at that time wedded to the doctrine of independence.1 Utility of the doctrine in practical testing. The preceding doctrine—as we shall see later—admits of usage throughout almost every kind and description of problem within the whole domain of individual differences of ability. For the present, however, we will only allude to two of the most obvious of these applications. The one consists in the power conferred of measuring any individual in a genuine manner (instead of giving a pseudo¬ average or level, see ch. v.). We can determine the magnitude of his g, which will tell us nearly everything about some of his abilities and something about nearly all of them (see p. 75). And then we can do the same as regards any of his s’s, one for each distinct kind of performance : this supplements and completes the information supplied by his g. For the details of calculating g and s, see the appendix, pp. xvii-xviii. The other immediate application of the doctrine is in the construction of mental tests. We are enabled to ascertain just the degree of accuracy with which any given test, or series of them, will measure either a person’s g or any of his s’s. Further, we learn how this degree of accuracy may be raised to its maximum. Procedures for both purposes are given and explained in the appendix, pp. xviii-xix. We can already see, too, that some crude approach to¬ wards measuring g can be obtained by the seemingly un¬ scientific course of throwing very miscellaneous tests into a common hotchpot. So doing does not indeed supply an average, or even a representative sample, of the person’s abilities ; anything of the sort seems to be for ever pre¬ cluded by the impossibility of fulfilling the necessary pos¬ tulates (see ch. v. pp. 62-64). What the pooling does effect is to make the influences of the many specific factors more or 1 Partridge, for instance, wrote about that time as follows : “ If now Spearman's method be valid, there is decided correlation among mental abilities, and the conclusion of many, especially among American investi¬ gators, are wrong.” Outline of Individual Study, 1909, p. 34.
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