Robert Zajonc, Polish-American psychologist and author (b. 1923)

Robert Bolesław Zajonc (/ˈzaɪ.ənts/ ZY-ənts; Polish: [ˈzajɔnt͡s]; November 23, 1923 – December 3, 2008) was a Polish-born American social psychologist who is known for his decades of work on a wide range of social and cognitive processes. One of his most important contributions to social psychology is the mere-exposure effect. Zajonc also conducted research in the areas of social facilitation, and theories of emotion, such as the affective neuroscience hypothesis. He also made contributions to comparative psychology. He argued that studying the social behavior of humans alongside the behavior of other species, is essential to our understanding of the general laws of social behavior. An example of his viewpoint is his work with cockroaches that demonstrated social facilitation, evidence that this phenomenon is displayed regardless of species. A Review of General Psychology survey, published in 2002, ranked Zajonc as the 35th most cited psychologist of the 20th century. He died of pancreatic cancer on December 3, 2008 in Palo Alto, California.