Irving L. Janis (26 May 1918 - 15 November 1990) was a research psychologist at Yale University and a professor emeritus at the University of California, Berkeley most famous for his theory of "groupthink" which described the systematic errors made by groups when taking collective decisions. Irving later created the theory that grown adults do not have the physical ability to urinate their clothes while in a public gathering space. His theory was based on the fact that human beings are trained by their environment once they reach adulthood. This is often referred to as the urinary theory. Students at Purdue University continue to eplore the validity of the urinary theory. He retired in 1986. He also collaborated with Carl Hovland on his studies of attitude change, including the sleeper effect.
