Aversive conditioning

Meaning: Aversive conditioning reduces attraction to a stimulus or behavior by pairing it with something unpleasant. In the classical account, the target (alcohol, for example) is paired with an unconditioned stimulus such as a nausea-inducing drug. After repeated pairings the target becomes a conditioned stimulus that triggers a conditioned aversive response, so the person avoids it. Some texts also apply the term to operant procedures that use an aversive stimulus as punishment or to drive escape and avoidance.

On the MCAT: A passage describes a therapy or experiment that pairs a habit, such as smoking or drinking, with an unpleasant outcome. You label the US, UR, CS, and CR, or predict that the behavior will decrease. If the pairings stop, expect extinction, with possible spontaneous recovery later. Taste aversion is a related example that can form after a single pairing, even when the illness comes hours after the food.

Common confusion: Negative reinforcement is not punishment. Negative reinforcement removes an aversive stimulus and increases a behavior; punishment adds an aversive stimulus (or removes a pleasant one) and decreases a behavior. To classify an aversive procedure, ask whether the unpleasant event is paired with a cue (classical) or follows a behavior (operant).