In studies on stress and immune function, rats that received electric shocks were unlikely to develop ulcers if the

• A. shocks were paired with loud noises
• B. rats had control over the shocks
• C. shocks were unpredictable
• D. rats were isolated from other rats

Answer: (B)

Verified step by step guidance

1. Step 1: Understand the context of the problem, which involves the relationship between stress (electric shocks) and immune function (development of ulcers) in rats.
2. Step 2: Recognize that the key variable affecting ulcer development is the rats' perception of control or predictability over the stressor (electric shocks).
3. Step 3: Analyze the options given: whether rats had control over shocks, whether shocks were unpredictable, or whether rats were isolated, and consider how each factor influences stress response and immune function.
4. Step 4: Recall psychological research findings that show when animals have control over a stressor, their stress response is reduced, leading to fewer negative health outcomes like ulcers.
5. Step 5: Conclude that the correct explanation is that rats were unlikely to develop ulcers because they had control over the shocks, which mitigated the stress impact on their immune function.