What year did BF Skinner develop the incentive theory?

B.F. Skinner did not specifically develop the incentive theory; rather, he is known for his work in behaviorism and operant conditioning. His research, particularly in the 1930s and 1940s, focused on how behaviors can be shaped by reinforcement and punishment. The concept of incentive theory, which emphasizes the role of external rewards in motivating behavior, is more broadly associated with various psychological theories rather than a single year or individual.