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.

    164/474 page 152
    ensuing correlations were found not to satisfy the criterion then used. But, doubtless, both the teachers and the fellow- pupils were acquainted with the school success, and in large measure based their estimates upon this; for this reason the (3) and the (4) did not supply independently obtained data.1 Some special cases. Rather an exceptional case, but still of considerable interest, is afforded by the following corre¬ lations which Baldwin found between six successive appli¬ cations of the Binet test-series at intervals of six months. 1 2 3 4 5 6 I — •85 73 •77 •8l •8l 2 •85 — •84 •80 •8l 75 3 - 73 •84 — 91 •83 79 4 - 77 •80 •91 — •9r •86 5 - •81 •81 ■83 •91 — •94 6 - •81 75 •79 •86 1 *94 — Here, a rash reasoner might jump to the conclusion that he had before him the very model case of the two factors, one always constant (“ intelligence ”), and the other varying each time independently (the errors of the successive measure¬ ments). In point of fact, however, the median of the observed tetrad differences comes to *072, which is far greater than their probable error, -016, and therefore cannot be ascribed merely to sampling.2 Any surprise at such a result is dissipated by recalling that the Binet tests continu¬ ally change in nature as the age of the testee increases (see ch. v. pp. 68-69). Consequently, the tests for any two neighbouring ages will have much in common that does not extend to ages farther apart.3 1 Am. J. Psych. 1909, xx. 2 It should be noted that the only probable error so far determined is for any single tetrad difference. The probable error for the median (or average) must certainly be much smaller, but we do not yet know how much smaller. 3 For a very elaborate and exact investigation of this matter, see The Constancy of “ G ” by Slocombe, Brit. J. Psych. 1926.
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