Questions of the Day and of the Fray number 9: Pearson, Karl. 1914. Mendelism and the Problem of Mental Defect. III. On the Graduated Character of Mental Defect and on the need for Standardizing Judgments as to the Grade of Social Inefficiency Which Shall Involve Segregation (London: Dulau and Co.). 51 pp.
Summary
Questions number 7-9 comprise a sustained critique, primarily by the Galton Laboratory, against the American Eugenics Record Office (E.R.O.) and its dogmatic application of Mendelian theory to human mental defect. See Questions number 7, Questions number 8, and Questions number 9.
Pearson continues the case developed in Questions number 7 and 8, emphasizing that mental defect is a continuously varying character, necessitating standardized judgment for segregation.
Pearson argues against the genetic advice to let “Weakness marry strength” by showing that this practice would still leave a latent taint well above the general population level for generations. He highlights the contradiction in Davenport’s work, where the same men are arbitrarily classified as normal, latent, or patent defectives to justify Mendelian rules.
The paper reiterates that physical stigmata cannot easily differentiate the large majority (87% to 90%) of non-specific mentally defective children. Drawing on Jaederholm’s data (Questions 08), Pearson concludes that only the extreme “tail” of the distribution (10% to 20%, or those with four years or more of mental defect) can be safely differentiated purely by intelligence testing. Since the boundary is ambiguous, Pearson urges that the decision to segregate must be based on formalized standards of social inefficiency and require development of accurate “tests of self-control” and “moral judgment” by psychologists, rather than relying on the vague “personal equation” of authorities.
Questions of the Day and of the Fray number 9:
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