Questions: No matter the type of punishment involved, the primary purpose of punishment is to increase the probability of a behavior, decrease the likelihood of a behavior, shape desired behavior, or control the consequences of desired behavior.

The answer is: decrease the likelihood of a behavior.

Explanation for each option:

1. Increase the probability of a behavior: This is incorrect. Increasing the probability of a behavior is typically the goal of reinforcement, not punishment. Reinforcement is used to encourage a behavior to occur more frequently.

2. Decrease the likelihood of a behavior: This is correct. The primary purpose of punishment is to reduce or eliminate undesirable behavior. Punishment is intended to make a behavior less likely to occur in the future by introducing an unpleasant consequence or removing a pleasant stimulus following the behavior.

3. Shape desired behavior: This is incorrect. Shaping desired behavior is more closely associated with reinforcement strategies, particularly positive reinforcement, where successive approximations of a desired behavior are rewarded until the final behavior is achieved.

4. Control the consequences of desired behavior: This is incorrect. Controlling the consequences of desired behavior is not the primary purpose of punishment. Instead, it is more related to reinforcement, where the consequences are managed to encourage the desired behavior.