An Urchin in the Storm: Essays about Books and Ideas by Stephen Jay Gould

Author:Stephen Jay Gould [Gould, Stephen Jay]
Language: eng
Format: epub
Publisher: W. W. Norton & Company
Published: 2010-11-29T08:00:00+00:00

Jensen devotes most of his book to showing that S-bias does not affect mental tests (or that S-bias can be corrected when it does exist). Yet I found nothing surprising in his densely documented demonstration that tests are unbiased in this sense. It would be a poor reflection indeed on the technical competence of psychometricians if, after nearly a century of effort, they had found no way to eliminate such an elementary and undesirable effect.

Thus, in saying that the tests are unbiased, Jensen has only managed to show that the lower black and higher white average scores lie on the same line (see Figure 2). And this unsurprising demonstration says nothing at all about the vernacular charge of bias: Does the lower black mean reflect environmental deprivation rather than inherent ability (V-bias)?

Of course, Jensen admits this. He distinguishes his notion of bias (S-bias) from our vernacular idea of fairness to all cultures. He also admits that such fairness cannot be defined objectively and thus undermines his own larger case: “One can determine with objective statistical precision how and to what degree a test is biased with respect to members of particular subpopulations. But no such objective determination can be made of the degree of culture-loadedness of a test. That attribute remains a subjective and, hence, fallible judgment…. The term ‘bias’ is to be kept distinct from the concept of fairness-unfairness.”

Yet these brave words are obfuscated or diluted throughout the book for three reasons. First, although he makes the distinctions fairly and forthrightly, he buries them on two pages in the middle of a lengthy work, and does not emphasize them thereafter. Second, Jensen correctly points out that some kinds of S-bias may have an environmental source. (The higher y-intercept of whites in Figure 1, leading to higher school grades among whites than blacks for the same test score, may reflect environmental advantages not measured by the test.) Thus, the concepts of S-bias and environmental difference become subtly conflated (and one easily slips into the false conclusion that tests without S-bias cannot record differences of environment)—even though the existence of S-bias is irrelevant to the key question about environment that has sparked the whole debate: does the lower black mean reflect environmental disadvantages? Indeed, Jensen’s 1969 article argued that the mean differences could not be attributed to V-bias because they are primarily genetic in origin.

Third, and most importantly (and annoyingly), Jensen, after making clear distinctions between S-bias and “culture fairness,” then proceeds to confuse the issue completely by using “bias” in its ordinary vernacular sense over and over again. He speaks, for example, of “the hypothesis that, when the Stanford-Binet is administered to any population other than the original normative sample, the different population should score lower than the normative sample because of cultural biases.” In another place he speaks of two tests that were “culturally biased” to award rural or urban children the higher score. These passages speak of mean differences between groups that may lie on the same line in plots of test scores versus criterion.

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