Operant conditioning (also called instrumental conditioning) is the process by which voluntary behavior is shaped by its consequences. Actions followed by favorable outcomes (reinforcement) become more likely, while actions followed by unfavorable outcomes (punishment) become less likely. B. F. Skinner systematized this form of learning, developing the Skinner box (operant chamber) and demonstrating that complex behaviors could be built through the systematic application of reinforcement contingencies.
Reinforcement and Punishment
Four consequence types are defined by two dimensions: whether the consequence is added or removed, and whether behavior increases or decreases. Positive reinforcement adds a pleasant stimulus (food reward → behavior increases). Negative reinforcement removes an aversive stimulus (pain relief → behavior increases). Positive punishment adds an aversive stimulus (shock → behavior decreases). Negative punishment removes a pleasant stimulus (loss of privileges → behavior decreases).
Shaping and Chaining
Complex behaviors that would never occur spontaneously can be established through shaping — reinforcing successive approximations to the target behavior. Skinner shaped pigeons to turn in circles, play ping-pong, and guide missiles by reinforcing each small step toward the desired behavior. Chaining links a series of simple behaviors into a complex sequence, with each behavior serving as a discriminative stimulus for the next.
Edward Thorndike's Law of Effect (1898) was the precursor to operant conditioning: "responses followed by satisfying consequences are strengthened, while responses followed by annoying consequences are weakened." Thorndike observed cats in puzzle boxes gradually learning to escape, with successful responses becoming more frequent over trials. His work established the experimental study of instrumental learning and the principle that consequences select behavior.
Cognitive Aspects
Modern understanding recognizes cognitive dimensions of operant conditioning. Tolman's latent learning experiments showed that rats learned maze layouts even without reinforcement, demonstrating that learning and performance are separable. Expectancy theories propose that animals learn outcome expectations rather than simple stimulus-response habits. The role of prediction error (the discrepancy between expected and actual outcomes) parallels findings in classical conditioning and connects to dopamine-based reinforcement learning in the brain.
Applications
Operant conditioning principles underlie behavior modification, token economies, applied behavior analysis for autism, animal training, gamification, and many educational practices. Understanding reinforcement schedules, the timing of consequences, and the role of discrimination and generalization allows practitioners to design effective interventions for behavior change in clinical, educational, and organizational settings.