This essay examines the reception by the medical and eugenic communities of Lionel Penrose’s research on “mental deficiency” in the 1930s. In 1928 Lionel Penrose began work at the Royal Eastern Counties Institution in Colchester, employed by the Medical Research Council to investigate the causes of “mental deficiency”.  The final Colchester report, of which I was able to obtain an early draft, was published in 1938. Penrose’s work at Colchester contributed to the publication of two books: Mental Defect (1933) and The Influence of Heredity on Disease (1934). The Colchester report, entitled “A Clinical and Genetic Study of 1280 Cases of Mental Defect,” argued for a combination of genetic and environmental causes behind various mental disabilities. It proved hugely influential on later developments in the genetical study of mental disorders.
Tessa Mair wrote this post. It was first submitted in 2019 as part of a postgraduate degree qualification in UCL Department of Science and Technology Studies (STS). It appears here in edited form, with the permission of the author.Citation: Tessa Mair (2022). Reception of Lionel Penrose’s Study on “Mental Deficiency” in 1930s Britain. Legacies-of-Eugenics.org. Published 15 January 2022.
Before outlining the structure of the essay, I want to offer a brief note on the terminology used in this paper. The analysis will employ terms that were considered correct and scientific in the context of 1930s Britain. This terminology is no longer appropriate and rightfully deemed unscientific. However, this paper will employ the contemporary language from primary sources. The following terms will be referred to, in quotation marks: “mental deficiency or mentally defective,” “mongol(ism)” (i.e. Down’s Syndrome), “feeble-minded(ness),” “sub-cultural amentia,” “dull,” “simple(ton(s)),” “imbecile(s),” “cretin(ism)” (i.e., thyroid hormone imbalance) and “idiot(s).”
This essay will begin with an overview of Penrose’s work at the Colchester institute and the conclusions he reached about “mental deficiency” as outlined in his published works. Second, the reception of Penrose’s work from the scientific community will be examined. Lastly, the reception of Penrose’s work by the Eugenics Society will be presented as an analysis of discourse at the annual Galton dinners, before coming to a conclusion.
Penrose on Heredity and “Mental Defect”
Penrose stressed that the patients at the Colchester institute “do not form a homogeneous group”.  Penrose pointed out the importance of intelligence and performance testing in certifying an individual as “mentally deficient,” as it was “possible for a person to be certified feeble-minded on account of social insufficiency although his mental ratio may be within normal limits”.  Penrose’s report included three main sections: “Family History Investigation”, “Analysis by Clinical Classification”, and “Genetic Comparisons”. 
Penrose investigated family histories, recording the occurrence and type of “mental deficiency” in family members of individuals at the institute, as well as whether paternal occupation and conditions of the home played a role in the occurrence of disorders.  Investigation into family histories revealed that the percentage of “mental defect” among parents and siblings of patients was estimated as only 7-8%. Moreover, “deficient” family members were more frequent when concerning patients of a higher intelligence grade. 
Penrose classified patients based on clinical assessment and stressed that the groups be treated distinctly. He also emphasised distinguishing between physical and psychological disorders.  Penrose provided two key findings in this section. Firstly, he associated “mongolism” with increasing maternal age.  Secondly, consanguinity, i.e., being blood-related, was common in the parents of diplegic patients.  Moreover, Penrose revealed the link between endocrine imbalances, such as, for example, hyperthyroidism, leading to types of psychopathy. Eugenicists often linked “feeble-mindedness” to societal issues such as crime and theft.  In contrast, Penrose chose to not include “social errors, like disobedience, promiscuity and occasional theft” in his analysis of psychopathy. 
The portion of the report relating to genetics outlined several key points. Firstly, it argued familial incidences of disorders suggested the involvement of genetic factors.  Secondly, by correlating consanguinity with certain disorders, Penrose deduced which disorders were likely determined by recessive genes.  Thirdly, Penrose associated certain disorders with dominant genes.  Lastly, Penrose discussed the importance of environmental factors in determining disorders, pointing out that identical twins could have different mental grades, and that “deficient” parents could give birth to unaffected children. 
Penrose’s book, Mental Defect was intended to be a guide for doctors and lay persons on the problems involved in studying “mental deficiency”. He noted the field is “held up to…preconceived dogmas,” and complained about it being “coupled with the ideas of sterilisation and the lethal chamber”.  Here ,Penrose was alluding to his belief that scientific progress was being impaired by eugenic ideas.  Moreover, Penrose rejected beliefs that heredity was the sole cause of “feeble-minded” individuals, referring to this line of thinking as a “cloak for ignorance”.  Penrose also criticised the UK Mental Deficiency Act of 1913, pointing out that its definitions of “mental deficiency” “make no pretence as scientific usefulness”.  Indeed, Penrose noted an “increasing tendency to regard criminal offences… as indicators of mental disorder”.  This suggests that Penrose viewed education and further research as the solution: tackling the subject requires “throw(ing) aside all social and moral prejudices”. 
Penrose further emphasised the role of environment in Mental Defect, pointing out that children with “sub-cultural amentia,” i.e., “feeble-mindedness,” were also born to “parents of the highest social standing”.  This challenged the eugenic view that “feeble-mindedness” was inherent to lower social classes. With reference to data that suggested more “sub-cultural amentia” among lower social classes, Penrose proposed this might be environmentally driven.  When discussing the treatment of “mental deficiency,” Penrose recommended improvements in education, psychotherapy and socialisation.  In disorders affecting physical well being, Penrose recommended thyroid gland extract for “cretinism,” and glasses for affected eyesight in “mongolism”.  Penrose’s suggestions were focused on treating the symptoms. This is summed up nicely in Penrose’s conclusion, where he wrote that sterilisation as a treatment was “subject to a great number of fallacies which are sufficient to invalidate it”. 
Penrose employed his own scientific research at Colchester to contradict existing eugenic solutions. In The Influence of Heredity on Disease, Penrose attributed decreasing incidences of diseases such as smallpox by the “application of scientific discoveries in medicine”.  Referring to sterilisation as a “treatment” that hastens human progress, he writes, “if natural selection had worked rapidly we should have had no…diseases to combat”.  Moreover, regarding the eugenic aim to “breed the best possible race”, he wrote we “cannot foresee the future environment of the human race and…cannot be certain what characters to breed for” and that “a stock which is entirely homogeneous may be ill-adapted to environmental changes”.  Penrose’s consistent application of modern evolutionary and genetic theory speak to the progressive nature of his work, and the influence it had on his own eugenic thought is exemplified by his quote: “generally speaking, it is unwise to be unduly optimistic about the results of eugenic measures in medicine”. 
Reception from the medical and scientific community
Considering that Penrose’s work on “mental deficiency” was formative in its field, it is crucial to understand how the medical and scientific community responded. In order to understand the reception, I will analyse reviews of Penrose’s books Mental Defect (1932) and The Influence of Heredity on Disease (1934) from contemporary medical and scientific journals.
The reactions to Mental Defect were overwhelmingly positive. A review from The British Journal of Inebriety described the work as “informing, suggestive and provocative…will certainly arouse discussion among all the classes” – revealing the radical nature of the book was well-received by the journal.  In a similar way, The Cambridge Review commented that Penrose was “not averse from making challenging statements”.  Clearly, the scientific community acknowledged the controversial, yet important, nature of Penrose’s work. Indeed, the same review also noted, with regards to Mental Defect, that there was “no better book on the subject in the English language”.  Penrose’s criticisms of sterilisation were also received exceedingly well. A review from Nature remarked, “It is gratifying to read a sane account of sterilisation.” Moreover, the same review acknowledged the “extreme importance of educating public opinion (on “mental deficiency”)”.  Not only was Penrose’s book commended, it was also regarded as necessary by the scientific community. Similarly, commenting on sterilisation as a “cure”, The Medical Officer noted that “Dr Penrose exposes the fallacies which invalidate this simple view”.  This review acknowledges the role of Penrose’s work on modern genetics and heredity, and that scientific advancement was crucial to contradict sterilisation.
The reception of The Influence of Heredity on Disease was equally optimistic. A review from the British Medical Journal called it an “important and valuable study” and commented how “extremely tempting it is to assume, when no cure for a disease is known, that its origins are hereditary”.  Here, the power of environment in both causing and providing amelioration of diseases, which Penrose stressed, is acknowledged. Various journals also comment on the role of eugenics in medicine. Indeed, the British Journal of Medical Psychology stated that Penrose’s work “should certainly make us cautious in promising this or that national benefit from eugenic reform”.  Similarly, the Liverpool Medico-Chirurgical Journal wrote that Penrose discusses “why most practical eugenist enterprise would be liable, in the existing state of knowledge, to defeat its own object, and possibly make matters worse”. 
In addition to reviews of Penrose’s books, a survey of articles published by The Lancet in the 1930s on Penrose’s work reveals that the scientific community supported his achievements. A 1934 article entitled “Mongolism and Maternal Age” supported Penrose’s suggestion that maternal age was a key environmental cause of Down’s Syndrome.  Another article entitled “Human Genetics”, which summarised the proceedings of the 7th International Genetics Congress in Edinburgh in 1939, described work on human genetics as of “greatest interest to our readers”.  This reveals the increasing interest in research in this particular field, in which Penrose was a forerunner. Lastly, a 1938 article entitled “The Familial Incidence of Mental Defect” agreed with Penrose’s criticisms of governmental treatment of “mental defect,” noting that “the legal definition of defect is clearly not very helpful, being necessarily framed for administrative purposes and equivalent to a diagnosis of social incompetence”.  We can clearly see, in the scientific community, a move away from the view of “mental defect” as purely a social problem.
Reception from the Eugenics Society
To elucidate the “mood” of the Eugenics Society during the 1930s – with specific attention paid to the development of attitudes towards “mental defect” – newspaper articles recounting discussions at the annual Galton Lectures were analysed. While no direct references to Penrose were identified in these articles, the Eugenics Society was certainly aware of Penrose’s achievements, and the Society’s official journal, Eugenics Review, frequently commented on his work. The Eugenic Society in interwar Britain aimed to promote the procreation of the “desirable class,” while limiting the procreation of the “social problem group”. Moreover, the “social problem group” was thought to consist primarily of “feeble-minded” individuals, a characteristic assumed to be solely hereditary. This left sterilisation as the solution to the “burden” of the “feeble-minded” on society. 
Before Penrose’s publications, the discourse at the 1932 Galton Lecture, reported by the Public Assistance Journal, focused on the “diseased” lower classes. Mr. E. J. Lidbetter, a member of the society, gave a lecture on the “social problem group”. During his lecture, Lidbetter used pedigree charts and tables to “scientifically” prove the “effects of diseased inheritance”.  Lidbetter stressed that “the defective person…left a trail on record behind him wherever he went…carrying the seeds of infection to the next generation”. These “seeds of infection” were recessive genes. His strong use of language impressed on the crowd the importance of controlling the reproduction of the “social problem group,” emphasising the need for “still more administrative machinery”. Moreover, improving the environment of the “social problem group” was not addressed.
By 1936, members of the Eugenics Society began to engage with Penrose’s research. Indeed, Julian Huxley, a British biologist and prominent member of the Eugenics Society, demonstrates the influence of Penrose’s work on eugenicist thought. At the 1936 annual dinner, Huxley gave a talk on the superiority of the higher classes. Interestingly, as an article in the Daily Telegraph documents, Huxley commented that the current eugenic effort was too focused on “palliative” measures such as sterilisation. Instead, he stated, the focus should be directed towards the “equalisation of social environment for different classes,” as this would be the only way to give a scientific basis to the supposed physical and mental superiority of higher classes.  While the aim here was still clearly to “prove” the eugenic idea that higher classes were biologically superior, Huxley does introduce the notion of environmental influence on heredity, an idea which Penrose established through his work.
Penrose’s research may have altered some people’s views about the legitimacy of eugenics, but his work proved no panacea. The Eugenics Society continued to propagate its long-held views about promoting the “best” individuals in society. Perhaps as a tweak, they tended to promote the view that only individuals of higher “fitness” could benefit from the environmental improvement efforts that Penrose suggested. For example, in response to a 1936 National Health Campaign recommending accessible physical exercise, Professor John Ryle, a British physician and eugenicist, stressed that individuals of a “poor pedigree” would not benefit from this proposal.  Undeniably, this contradicts Penrose’s suggestion that environment played a key role; instead, Ryle insisted that heredity played a dominating role in an individual’s “fitness.” The Journal of Education reported in 1938 that Sir Farquhar Buzzard (another member of the Eugenics Society), expressed similar sentiments. He commented on the degeneration of the population and argued that “every scientific means must be used to ensure high quality”. <
Penrose continued to be a critic of the Eugenics Society. For instance, when invited to deliver their annual Galton Lecture, he was scathing about the Society’s core aims and ambitions. 
Lionel Penrose’s research on the genetic and environmental causes of “mental deficiency” was seminal. Not only did Penrose provide a scientific differentiation of disorders and their causes, but he exposed the fallacy of sterilisation as a “cure” for the “social problem group” and how the strive for a “fitter” population clashed with emerging genetic and evolutionary theory. The reception of Penrose’s work was analysed in two groups: the scientific community and the Eugenics Society. In general, the scientific and medical community was highly supportive of Penrose’s conclusions. The Eugenics Society, however, remained primarily focused on the traditional eugenic goal of increasing population “fitness” through the reduction of the “social problem group,” despite Penrose’s contributions to scientific advancement.
1 D. C. Watt, “Lionel Penrose, F.R.S. (1898–1972) and Eugenics: Part One,” Notes and Records of the Royal Society of London 52 (1), (1998), 137-51.
2 Lionel S. Penrose, First Draft of Colchester Report, 21 April 1937, PENROSE/2/19/2, UCL SC, p. 9.
3 Ibid., p. 26.
4 Ibid., p. 5.
5 Ibid., p. 24.
6 Ibid., pp. 56-58.
7 Ibid., p. 65.
8 Ibid., p. 69.
9 Ibid., p. 84.
10 Michael Boulter, Bloomsbury Scientists: Science and Art in the Wake of Darwin (London: UCL Press, 2017).
11 Penrose, First Draft, p. 110.
12 Ibid., p. 124.
13 Ibid., p. 127.
14 Ibid., p. 130.
15 Ibid., p. 132, 194.
16 Lionel S. Penrose, Mental Defect (London: Sidgwick and Jackson, 1933), pp. 20, 29.
17 Boulter, Bloomsbury Scientists.
18 Penrose, Mental Defect, p. 36
19 Ibid., p. 41.
20 Ibid., pp. 43-44.
21 Ibid., p. 47.
22 Ibid., p. 323.
23 Ibid., p. 332.
24 Ibid., pp. 346-350.
25 Ibid., pp. 344, 356.
26 Ibid., p. 370.
27 Lionel S. Penrose, The Influence of Heredity on Disease (London: H. K. Lewis & Co, 1934), p. 74.
28 Ibid., p. 74.
29 Ibid., pp. 76-77.
30 Ibid., p. 75.
31 ‘Review of Mental Defect by Lionel S. Penrose’, The British Journal of Inebriety, PENROSE/2/18/5.
32 ‘Review of Mental Defect by Lionel S. Penrose’, The Cambridge Review (26 January 1934), PENROSE/2/18/5.
34 Review of Mental Defect by Lionel S. Penrose’, Nature (10 March 1934), pp. 373-4, PENROSE/2/18/5.
35 ‘Review of Mental Defect by Lionel S. Penrose’, The Medical Officer Vol. L, No. 16 (14 October 1933), p. 166, PENROSE/2/18/5.
36 ‘Review of Heredity and Disease’, The Medical Officer (14 April 1934), PENROSE/2/18/5.
37 ‘Review of The Influence of Heredity on Disease by Lionel S. Penrose’, The British Journal of Medical Psychology Vol. XIV, No. 3 (1934), p. 294, PENROSE/2/18/5.
38 Hughes, Edmunds, ‘Review of The Influence of Heredity on Disease’, The Liverpool Medico-Chirurgical Journal No. 10 (1934), PENROSE/2/18/5.
39 ‘Mongolism and Maternal Age’, The Lancet Vol. 2, No. 5795 (22 September 1934), p. 665.
40 ‘Human Genetics’, The Lancet Vol. 2, No. 6055 (16 September 1939), pp. 663-665
41 ‘The Familial Incidence of Mental Defect’, The Lancet Vol. 1, No. 5977 (19 March 1938), pp. 680-681.
42 Boulter, Bloomsbury Scientists.
43 ‘Mental Deficiency Problems’, Public Assistance Journal (18 February 1932), SAEUG/N/30/31.
44 ‘Super-Men of the Future’, Daily Telegraph (18 February 1936), SAEUG/N/30/31.
45 ‘Family Way to Health’, Daily Herald (14 February 1936), SAEUG/N/30/31.
46 Article from Journal of Education (April 1938), SAEUG/N/30/31.
47 Penrose, L. ‘The Galton Laboratory: Its Work and Aims’. Eugenics Review Vol. 41 (1949), pp. 17-27.
‘Family Way to Health’, Daily Herald (14 February 1936), SAEUG/N/30/31. ‘Human Genetics’, The Lancet Vol. 2, No. 6055 (16 September 1939), pp. 663-665
‘Mental Deficiency Problems’, Public Assistance Journal (18 February 1932), SAEUG/N/30/31, Wellcome Library.
‘Mongolism and Maternal Age’, The Lancet Vol. 2, No. 5795 (22 September 1934), p. 665.
‘Review of Heredity and Disease’, The Lancet Vol. 1, No. 5783 (30 June 1934), p. 1402, PENROSE/2/18/5, UCL Special Collections.
‘Review of Heredity and Disease’, The Medical Officer (14 April 1934), PENROSE/2/18/5, UCL Special Collections
‘Review of Mental Defect by Lionel S. Penrose’, Nature (10 March 1934), pp. 373-4, PENROSE/2/18/5, UCL Special Collections.
‘Review of Mental Defect by Lionel S. Penrose’, The British Journal of Inebriety, PENROSE/2/18/5, UCL Special Collections.
‘Review of Mental Defect by Lionel S. Penrose’, The Cambridge Review (26 January 1934), PENROSE/2/18/5, UCL Special Collections.
‘Review of Mental Defect by Lionel S. Penrose’, The Medical Officer Vol. L, No. 16 (14 October 1933), p. 166, PENROSE/2/18/5, UCL Special Collections.
‘Review of The Influence of Heredity on Disease by Lionel S. Penrose’, The British Journal of Medical Psychology Vol. XIV, No. 3 (1934), p. 294, PENROSE/2/18/5, UCL Special Collections.
‘Reviews: Disease and Heredity’, The British Medical Journal (19 May 1934), p. 896, PENROSE/2/18/5, UCL Special Collections.
‘Reviews: Mental Defect’, The British Medical Journal (10 February 1934), p. 238.
‘Super-Men of the Future’, Daily Telegraph (18 February 1936), SAEUG/N/30/31, Wellcome Library.
‘The Familial Incidence of Mental Defect’, The Lancet Vol. 1, No. 5977 (19 March 1938), pp. 680- 681.
Article from Journal of Education (April 1938), SAEUG/N/30/31.
Hughes, Edmunds, ‘Review of The Influence of Heredity on Disease’, The Liverpool Medico-Chirurgical Journal No. 10 (1934), PENROSE/2/18/5, UCL Special Collections.
Penrose, Lionel S., First Draft of Colchester Report, 21 April 1937, PENROSE/2/19/2, UCL Special Collections.
Penrose, Lionel S., Mental Defect (London: Sidgwick and Jackson, 1933).
Penrose, Lionel S., The Influence of Heredity on Disease (London: H. K. Lewis & Co, 1934).
Penrose, Lionel S., ‘The Galton Laboratory: Its Work and Aims’. Eugenics Review Vol. 41 (1949), pp. 17-27.
Boulter, Michael, Bloomsbury Scientists: Science and Art in the Wake of Darwin. London. UCL Press., (2017).
Watt, D. C.,“Lionel Penrose, F.R.S. (1898–1972) and Eugenics: Part One,” Notes and Records of the Royal Society of London 52 (1), (1998), 137-51.
Author: Tessa Mair.
Citation: Tessa Mair (2022). Reception of Lionel Penrose’s Study on “Mental Deficiency” in 1930s Britain. Legacies-of-Eugenics.org. Published 15 January 2022. URL: TBC.
This essay was first submitted in 2019 as part of a postgraduate degree qualification in UCL Department of Science and Technology Studies (STS). It appears here in edited form, with the permission of the author.