The frequency of the use of deception in American psychological research was studied by reviewing articles from journals in personality and social psychology from 1921 to 1994. Deception was used rarely during the developmental years of social psychology into the 1930s, then grew gradually and irregularly until the 1950s. Between the 1950s and 1970s the use of deception increased significantly. This increase is attributed to changes in experimental methods, the popularity of realistic impact experiments, and the influence of cognitive dissonance theory. Since 1980 there appears to have been a decrease in the use of deception as compared to previous decades which is related to changes in theory, methods, ethical standards, and federal regulation of research.