How do negative reinforcement and punishment differ in their effects on behavior?

Negative reinforcement and punishment indeed have opposite effects on behavior, which is why this answer is correct.

Negative reinforcement involves the removal of an unpleasant stimulus to increase the likelihood of a behavior being repeated. For example, if a student studies hard to avoid the anxiety of failing a test, the removal of that anxiety serves as a negative reinforcer, thereby encouraging the behavior of studying. The focus here is on increasing desired behaviors by taking away negative outcomes.

On the other hand, punishment is designed to decrease a behavior by introducing an unpleasant consequence or removing a pleasant stimulus. For instance, if a child touches a hot stove and experiences pain, that painful consequence serves to reduce the likelihood of the child touching the stove again. In this case, the focus is on discouraging undesirable behaviors.

Thus, negative reinforcement strengthens behavior by alleviating negative conditions, while punishment weakens behavior through the introduction of unwanted outcomes or the removal of positive situations. This clear distinction in their effects substantiates why they are described as having opposite effects on behavior.