George W. Ainslie is an American psychiatrist, psychologist and behavioral economist. Unusual for a psychiatrist, Ainslie undertook experimental animal research in operant conditioning, under the guidance of Howard Rachlin. He investigated inter-temporal choice in pigeons, and was the first to demonstrate experimentally the phenomenon of preference reversal in favor of the more immediate outcomes as the choice point between two options, one delivered sooner than the other, is moved forward in time. He explained this in terms of hyperbolic discounting of future rewards, derived from ideas that Rachlin and others had developed from Richard Herrnstein's matching law. Ainslie then integrated these ideas with earlier experimental and theoretical work on inter-temporal choice, for example the st