In classical conditioning, which of the following best describes an unconditioned stimulus (US)?

• A. A stimulus that is learned through repeated association with another stimulus
• B. A stimulus that naturally and automatically triggers a response without prior learning
• C. A neutral stimulus that does not elicit any response before conditioning
• D. A response that occurs after conditioning has taken place

Answer: (B)

Verified step by step guidance

1. Understand the concept of classical conditioning, which involves learning through association between stimuli.
2. Identify the role of the unconditioned stimulus (US) in classical conditioning: it is a stimulus that naturally and automatically triggers a response without any prior learning.
3. Compare the unconditioned stimulus to other types of stimuli, such as the neutral stimulus (which initially does not elicit a response) and the conditioned stimulus (which elicits a response after learning).
4. Recognize that the unconditioned stimulus is different from learned stimuli because it produces an unconditioned response naturally, without conditioning.
5. Conclude that the best description of an unconditioned stimulus is 'a stimulus that naturally and automatically triggers a response without prior learning.'