What characterizes positive punishment?

Positive punishment is characterized by the presentation of an aversive stimulus following a behavior in order to decrease the likelihood of that behavior occurring in the future. This approach relies on adding something undesirable after an action, which creates a consequence that aims to discourage the behavior.

For example, if a child touches a hot stove and subsequently feels pain, that pain acts as a positive punishment that teaches them to avoid that behavior in the future.

The other choices describe different concepts in behavior modification. The removal of a reinforcing stimulus pertains to negative punishment, where something desirable is taken away to reduce a behavior. The introduction of a pleasant stimulus would be associated with reinforcement, aiming to increase a behavior rather than decrease it. Lastly, the removal of an aversive stimulus describes negative reinforcement, which increases the likelihood of a behavior by taking away an unpleasant condition. Thus, the defining feature of positive punishment is the presentation of an undesirable stimulus after a behavior, which is precisely reflected in the correct answer.