operant conditioning

Meaning: Operant conditioning grew from Thorndike's law of effect and is tied to Skinner. The learner acts, and the consequence shapes future behavior. Reinforcement increases a behavior; punishment decreases it. "Positive" means a stimulus is added and "negative" means one is removed. So positive reinforcement adds something pleasant, negative reinforcement removes something aversive, positive punishment adds something aversive, and negative punishment removes something pleasant. Shaping reinforces successive approximations of a target behavior.

On the MCAT: A passage describes an animal or person and a consequence, and you classify it into one of the four categories. Other questions use reinforcement schedules: fixed-ratio, variable-ratio, fixed-interval and variable-interval. Variable-ratio typically produces a high, steady response rate and is most resistant to extinction, the fading of a behavior once reinforcement stops. You may also read a cumulative response graph, where a steeper slope means a faster response rate.

Common confusion: Negative reinforcement is not punishment. It strengthens a behavior by removing something unpleasant, such as pressing a lever to stop a shock. Ask two questions: did the behavior increase or decrease, and was a stimulus added or removed? Operant conditioning also differs from classical conditioning, which pairs stimuli to produce involuntary responses.