Unknown author · Public domain

Stanley Milgram, shaped by the Holocaust and the trial of Adolf Eichmann, designed an experiment at Yale in 1961 to test how far ordinary people would go in obeying an authority figure's instructions to harm someone else — and found, to his own unease, that most would comply. He described the results in a 1963 paper and his 1974 book, Obedience to Authority, work that remains among the most cited, and most ethically debated, in the history of social psychology. He also originated the "small-world" research, at the University of Iowa, that gave rise to the idea of six degrees of separation.