Punishment is effective only when it wea­kens: Options Undesirable response Desirable response Positive response Negative response

To determine the effectiveness of punishment in relation to different responses, we need to understand the underlying principles of behavioral psychology.

Analyzing the Options

1. Undesirable response: This option suggests that punishment should weaken behaviors that are not desired or appropriate. In behavioral psychology, this aligns with the goal of punishment, which is to reduce specific negative behaviors.

2. Desirable response: Punishment should not weaken desirable responses, as this would be counterproductive to the goal of encouraging positive behaviors.

3. Positive response: This term could be interpreted as a favorable reaction or behavior. Punishment should ideally not affect positive responses negatively, as that could result in the extinction of useful behavior.

4. Negative response: This term usually refers to undesirable behaviors or responses, akin to undesirable responses. However, it may imply a broader set of negative behaviors rather than specifically the responses we aim to control.

Conclusion

Punishment is most effective when it weakens the undesirable response, as this is the primary intent of applying punishment within behavior modification frameworks. Thus, the correct answer is:

Final Answer: Undesirable response.