Final answer:
Negative reinforcement involves the removal of an unpleasant stimulus to increase the likelihood of a behavior's occurrence.
Step-by-step explanation:
The removal of an unpleasant stimulus to increase the probability of a behavior's occurrence is known as negative reinforcement. An example of this is when you put on a sweater because you are cold; the unpleasant stimulus (cold) is removed, which increases the likelihood that you will put on a sweater when cold in the future. This is different than punishment, which seeks to decrease a behavior. Positive reinforcement, on the other hand, would involve adding a pleasant stimulus to increase a behavior, such as giving a treat to a dog for fetching a ball.