(a) In classical conditioning, the organism associates one stimulus with another stimulus because the two stimuli occur closely together in time. In operant conditioning, the organism associates a...

(a) In classical conditioning, the organism associates one stimulus with another stimulus because the two stimuli occur closely together in time. In operant conditioning, the organism associates a response with its consequences. A response that is reinforced is strengthened (more likely to recur), whereas a response that is not reinforced is weakened (less likely to recur). In operant conditioning, the organism must make the correct response to receive reinforcement, (b) Negative reinforcement strengthens a response by removing something undesirable. If you have a headache and take Tylenol, and your headache goes away, this desirable consequence will make you more likely to take Tylenol the next time you have a headache. (If instead Tylenol does not cure your headache, the lack of reinforcement will weaken this response and make you more likely to select a different medication in the future.) Punishment is the opposite: it weakens a response by presenting something undesirable (or by removing something desirable), as when a child does something wrong and the parents respond with disapproval or a spanking. (c) Freud argues that the ego prevents undesirable id impulses from reaching consciousness. Skinner contends that removing unpleasant (aversive) thoughts is negatively reinforcing.