The Mismeasure of Man (Revised & Expanded) by Stephen Jay Gould

Author:Stephen Jay Gould [Gould, Stephen Jay]
Language: eng
Format: epub, pdf
Tags: science, Life Sciences, pol_guide, Biological Diversity
ISBN: 9780393340402
Google: RTjfmxTpsVsC
Amazon: 0393314251
Publisher: W. W. Norton & Company
Published: 1996-06-17T00:00:00+00:00

5.7a, 5.7b Zero was by far the most common value in several of the Alpha tests.

With all these acknowledgments, one might have anticipated Boring’s decision either to exclude zeros from the summary statistics or to correct for them by assuming that most recruits would have scored some points if they had understood what they were supposed to do. Instead, Boring “corrected” zero scores in the opposite way, and actually demoted many of them into a negative range.

Boring began with the same hereditarian assumption that invalidated all the results: that the tests, by definition, measure innate intelligence. The clump of zeros must therefore be made up of men who were too stupid to do any items. Is it fair to give them all zero? After all, some must have been just barely too stupid, and their zero is a fair score. But other dullards must have been rescued from an even worse fate by the minimum of zero. They would have done even more poorly if the test had included enough easy items to make distinctions among the zero scores. Boring distinguished between a true “mathematical zero,” an intrinsic minimum that cannot logically go lower, and a “psychological zero,” an arbitrary beginning defined by a particular test. (As a general statement, Boring makes a sound point. In the particular context of the army tests, it is absurd):

A score of zero, therefore, does not mean no ability at all; it does not mean the point of discontinuance of the thing measured; it means the point of discontinuance of the instrument of measurement, the test.… The individual who fails to earn a positive score and is marked zero is actually thereby given a bonus varying in value directly with his stupidity (p. 622).

Boring therefore “corrected” each zero score by calibrating it against other tests in the series on which the same man had scored some points. If he had scored well on other tests, he was not doubly penalized for his zeros; if he had done poorly, then his zeros were converted to negative scores.

By this method, a debilitating flaw in Yerkes’s basic procedure was accentuated by tacking an additional bias onto it. The zeros only indicated that, for a suite of reasons unrelated to intelligence, vast numbers of men did not understand what they were supposed to do. And Yerkes should have recognized this, for his own reports proved that, with reduced confusion and harassment, men who had scored zero on the group tests almost all managed to make points on the same or similar tests given in an individual examination. He writes (p. 406): “At Greenleaf it was found that the proportion of zero scores in the maze test was reduced from 28 percent in Beta to 2 percent in the performance scale, and that similarly zero scores in the digit-symbol test were reduced from 49 to 6 percent.”

Yet, when given an opportunity to correct this bias by ignoring or properly redistributing the zero scores, Yerkes’s statisticians did just the opposite. They exacted a double penalty by demoting most zero scores to a negative range.

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