(b. April 15, 1880, Prague, Czech.
d. Oct. 12, 1943, New Rochelle, N.Y., U.S.) German psychologist.
He taught at the Universities of Frankfurt and Berlin (1916–29) before immigrating to the U.S. to teach at the New School for Social Research (1933–43). With Wolfgang Köhler and Kurt Koffka (1886–1941), he was instrumental in establishing Gestalt psychology. Much of his work dealt with perception, though he also explored thinking and problem solving. His Productive Thinking was published posthumously in 1945.