In classical conditioning, when a stimulus delta (SΔ) is presented, a particular response is:

• A. reinforced immediately
• B. more likely to occur
• C. less likely to occur
• D. unaffected and occurs at the same rate

Answer: (C)

Verified step by step guidance

1. Understand the role of the stimulus delta (S\(\Delta\)) in classical conditioning. S\(\Delta\) is a discriminative stimulus that signals that a particular response will not be reinforced.
2. Recall that in classical conditioning, reinforcement increases the likelihood of a response, while the absence of reinforcement decreases it.
3. Recognize that when S\(\Delta\) is presented, it indicates that the conditioned stimulus will not be followed by the unconditioned stimulus, so the conditioned response is less likely to occur.
4. Compare the options: 'reinforced immediately' and 'more likely to occur' imply an increase in response frequency, which contradicts the function of S\(\Delta\).
5. Conclude that the correct interpretation is that the response is 'less likely to occur' when S\(\Delta\) is presented, because it signals no reinforcement.