Extinction occurs when a behavior that was previously reinforced is no longer reinforced, resulting in the behavior decreasing.

• A. The behavior is no longer reinforced, causing it to diminish.
• B. The behavior is reinforced to increase it.
• C. The behavior is punished to stop it.
• D. The behavior is rewarded to encourage repetition.

Answer: (A)

Extinction happens when the reinforcement that previously followed a behavior is withdrawn, so the behavior loses its payoff and tends to decrease. The driving idea is that reinforcement keeps a behavior going; without it, the behavior becomes less likely over time, and you may even see a brief spike right at first (an extinction burst) before it drops. In this scenario, the description matches extinction exactly: the behavior is no longer reinforced, causing it to diminish. The other options describe increasing reinforcement, using punishment, or rewarding to encourage repetition, which would not produce extinction.