reinforcement

Meaning: In operant conditioning, reinforcement is a consequence that makes the behavior before it more likely to recur. Positive reinforcement adds a stimulus (a treat after a lever press). Negative reinforcement removes an aversive stimulus (a buckled seat belt stops the alarm). Primary reinforcers meet biological needs, like food; conditioned reinforcers, like money, gain value by association.

On the MCAT: Passages give a schedule of reinforcement and ask for the response pattern. Ratio schedules depend on number of responses, interval schedules on elapsed time. Variable ratio gives a high, steady rate and the greatest resistance to extinction (gambling). Fixed ratio gives a high rate with pauses after rewards; fixed interval gives rising responding near the expected reward; variable interval gives a slow, steady rate. Partial reinforcement is learned more slowly than continuous reinforcement but extinguishes more slowly.

Common confusion: Negative reinforcement is not punishment. Negative means a stimulus is removed; reinforcement means the behavior increases. Punishment decreases behavior, whether it adds a stimulus or removes one.