The idea that there are two kinds of thinking, one fast and intuitive, the other slow and reflective, has multiple origins in philosophy and psychology. It is found in ancient Greek philosophy and in Freudian theory, to name but two examples (Frankish & Evans, 2009, p. 24). So while a number of late 20th-century authors have proposed some form of dual-process theory as an apparently original idea, none can truly be attributed as the original source. However, several authors have proposed dual-process accounts that were original to themselves and their immediate research fields and which had distinctive features. This happened, for example, in the study of attention (Schneider & Shiffrin, 1977), reasoning (Sloman, 1996; Wason & Evans, 1975), learning (Reber, 1993) and social psychology (Chaiken, 1980; Epstein, 1994).