The two main enemies of evolutionary ideas are the culturalists (within academia) and the creationists (outside). They are two arms of a pincer squeezing and marginalizing evolutionary ideas from the social sciences.
One such pincer movement occurred in the 1920s.
The culturalist arm within academia was led in the ’20s by Franz Boas, a leading anthropologist, who insisted that anthropology and the human sciences generally are simply about “culture” (and did not involve biology in any way).
The creationist arm was also particularly energetic in the 1920s. William Bryan Jennings was railing against “Social Darwinism,” that universal bugbear. Religious activists turned their attention not just to biologists but also to social scientists. They castigated all forms of evolutionism, including the social evolution idea that contemporary societies had evolved from primitive ones over long timescales.
Michael Liensch shows that in response to their campaigns social science textbooks were censored, removed, and rewritten. American social science deleted Darwinism and de-evolutionized itself.
The most troubling response, however, came in the form of self-censorship, as social scientists began recasting, rephrasing, and in some cases simply removing references to evolution from their classrooms and textbooks. Here they followed a strategy similar to that used by authors of some of the most popular biology texts of the 1920s, who were at this time systematically replacing references to evolution with terms such as “change,” “development,” or “growth,” removing charts or diagrams that showed humans as part of the evolutionary process, and relegating discussions of evolutionary theory to the end of the book, or simply removing them altogether.
The author of one introductory sociology book responded to attacks by in later editions
deleting all discussions of human origins, playing down the importance of the fossil record, and describing primitive man as “essentially as he is to-day.”
Another author renamed a textbook from Social Evolution to Cultural Change and also responded by
deleting chapters on heredity, the struggle for existence, and natural selection; removing diagrams of Haeckel’s evolutionary embryos and photos comparing the hands of humans and chimpanzees; and adding a discussion of the differences between biological, psychological, and cultural development in which he made it clear that “each follows different laws of change.”
In general
over the course of the decade many of the most popular social science textbooks … would all see similar revisions.
That is how Darwin was deleted, and evolution was eased out. Darwinism was censored.
Reference
Michael Lienesch, Abandoning Evolution: The Forgotten History of Antievolution Activism and the Transformation of American Social Science Isis 103.4 (2012) pp. 687-709 DOI: 10.1086/668963 Stable URL: http://www.jstor.org/stable/10.1086/668963 (Ungated version here)