Questions of the Day and of the Fray number 7: Heron, David. 1913. Mendelism and the Problem of Mental Defect. I. A Criticism of Recent American Work (London: Dulau and Co.). 62 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.
This paper argues that the E.R.O. work, particularly by Dr. C. B. Davenport, is detrimental to the true progress of Eugenics due to “fallacious methods of reasoning”.
Heron targets the dangerous eugenic rule “Weakness should marry strength”. This rule, based on the assumption that mental defect (RR) is a simple recessive, would result in seemingly normal offspring (DR hybrids), thereby hiding the latent defect for generations.
The paper alleges serious flaws in the E.R.O. research methods:
- Bias in Collection: Field-workers were instructed to specifically seek out individuals necessary to support Mendelian expectations (“make a special search”).
- Lack of Accuracy: Heron cites numerous contradictions and errors within Davenport and Weeks’s own published tables regarding the same individuals (e.g., individuals reported as having “died early” also recorded as having married and produced 12 children).
- Refuting Mendelian Rules: Most critically, the E.R.O.’s data fails the core Mendelian test: when two defective parents (RR x RR) mated, they still produced a substantial number of normal or “tainted” offspring (e.g., 10 exceptions out of 112 cases, and 15 exceptions out of 22 cases), contrary to the expected 100% defective outcome. Davenport attempted to dismiss these exceptions with arbitrary, non-scientific explanations. Heron also notes that Davenport continually changed his definition of alcoholism (labelling it normal, latent, or patent defect as needed) to fit his shifting theories.
Questions of the Day and of the Fray number 7
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