Rationality, American Politics, and the Science of Human Nature

This paper examines the interaction of the sciences of human nature and post-World War II American politics. In the 1950s and 1960s, cognitive scientists depicted humans as rational, autonomous, creative, and flexible thinkers. However, within two decades they had reversed course and begun to emphasize human irrationality. In the postwar period, these sciences portrayed humans as open-minded thinkers. This vision of human nature was used to show that the Soviet system was not only immoral, but also unnatural. At home, this account of rationality provided a nominally objective grounding for centrist politics. The new field of cognitive science helped to make the politics of open-mindedness invisible by contending that open-mindedness served as the essential criterion of universal human nature. This scientific vision of rationality was deployed to marginalize political protest and to inoculate Americans against McCarthyism by making them more open-minded and more “human.” By the late 1960s, the politics of open-mindedness shifted. Feminists and the members of New Left managed to claim that they best represented humanity, successfully appropriating the virtues of the open mind for themselves. Conversely, in the early 1970s, a newly energized right wing attacked social science for its “anti-American” focus on human creativity, autonomy, and equality. Responding to these challenges, cognitive scientists reversed course and began to emphasize that humans were naturally irrational. Led by Daniel Kahneman and Amos Tversky, social scientists shifted from looking at human capability to exploring how humans are, by nature, irrational. Starting in the late 1960s, a coalition of cognitive scientists and economists challenged the picture, previously advanced by their own fields, of humans as rational beings. This work formed the basis of behavioral economics, once the economics profession became more open to empirical evidence that “rational economic man” does not exist.