Eugenics Laboratory Lectures number 3: Elderton, Ethel M. 1909. The Relative Strength of Nurture and Nature (London: Dulau and Co.). 40 pp. Includes two Appendices: Appendix A, ‘Home Conditions and Eyesight’, by Karl Pearson (noted as reprinted from British Medical Journal), pp. 34–39, and Appendix B, ‘Cleanliness and Vision’, signed Karl Pearson, pp. 439–40.
Summary
The preface notes that this Lecture summarizes three Memoirs (V, VII, and VIII). Second edition is 1915, noted as ‘much enlarged edition’ of two parts (60 pp. in total): Part I. The Relative Strength of Nurture and Nature. Second edition, revised. By E. M. Elderton; and Part II. Some Recent Misinterpretations of the Problem of Nurture and Nature. First issue. By Karl Pearson.
The original 1909 lecture (Part I), authored by Ethel M. Elderton, uses quantitative data to argue that the influence of Nurture (environment) is insignificant compared to Nature (heredity). Drawing on extensive datasets from Edinburgh, Glasgow, and Manchester, the study examined the influence of factors like the mother’s employment, the father’s occupation, parental drinking habits, and overcrowding on children’s physical health (height, weight, eyesight) and intelligence.
Elderton demonstrates that correlation coefficients linking environmental measures to child characteristics are extremely small, often clustering near zero (e.g., $0.05$ to $0.14$) and sometimes even showing negative associations (worse environment associated with better condition). For instance, parental drinking had correlations ranging from $-0.03$ to $0.08$ with child intelligence, height, and weight. In contrast, internal Laboratory studies consistently showed the hereditary factor’s resemblance coefficients for close relatives ranged from 0.4 to 0.6. Elderton argues that social workers often mislead the public by citing raw figures (e.g., a percentage of children of drunkards who are tuberculous) without providing a comparative figure for the general population of the same class. Ultimately, the study asserts that environmental factors are ”practically negligible” compared with the direct effects of nature.
Changes Across Editions:
The lecture was transformed into a Second, Much Enlarged Edition published in 1915 (with an earlier issue around 1913/1914). This new edition retained Elderton’s data (Part I) while adding Part II: Some Recent Misinterpretations of the Problem of Nurture and Nature by Karl Pearson. Pearson’s addition was highly polemical, directly addressing critics (like Professor J. Arthur Thomson, Major Darwin, and Mr. A. M. Carr-Saunders) who misunderstood or misrepresented the Galton Laboratory’s findings. Pearson used tables (originally published in Lecture 6) to show the distribution of frequency for a long series of Nurture correlations (mean $\approx 0.03$) versus Nature correlations (mean $\approx 0.51$). He vehemently criticized critics for their lack of understanding of modern statistical methods, particularly multiple correlation, arguing that simply adding up environmental correlation coefficients (as proposed by critics) grossly misrepresents the true influence of Nurture. The inclusion of new data from Rochdale, Bradford, and Blackburn further enforced the conclusion that the environmental influence on infant welfare was statistically weak.
Eugenics Laboratory Lectures number 3
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