title: Frustration–aggression hypothesis
context: Frustration–aggression hypothesis, otherwise known as the frustration–aggression–displacement theory, is a theory of aggression proposed by John Dollard, Neal Miller, Leonard Doob, Orval Mowrer, and Robert Sears in 1939,[1] and further developed by Neal Miller in 1941[2] and Leonard Berkowitz in 1969.[3] The theory says that aggression is the result of blocking, or frustrating, a person's efforts to attain a goal.[4]
question: When did John Dollard propose the frustration–aggression–displacement theory?
answers: in 1939