Which statement describes a conditioned stimulus?

• A. Starts out as a neutral stimulus & becomes repeatedly paired with an unconditioned stimulus.
• B. An unlearned response that occurs naturally in reaction to the unconditioned stimulus.
• C. The association makes the neutral stimulus a conditioned stimulus, which eventually comes to trigger a conditioned response.
• D. A behavior to be reinforced.

Answer: (C)

In classical conditioning, a conditioned stimulus is a neutral signal that becomes meaningful after it’s paired with an unconditioned stimulus. Through repeated pairings, this neutral stimulus gains the power to elicit a response on its own, which is the conditioned response. The statement that best describes this is that the association makes the neutral stimulus a conditioned stimulus, which eventually comes to trigger a conditioned response. For example, a bell that initially doesn’t provoke a reaction becomes a conditioned stimulus after being paired with food; over time, the bell alone can make the dog salivate, which is the conditioned response. The other descriptions either talk about turning a neutral stimulus into a CS without mentioning the learned response, or describe the unconditioned stimulus/response, or refer to reinforcement concepts from operant conditioning rather than classical conditioning.