Final answer:
Initially, the clicker in operant learning is a neutral stimulus that does not elicit any response until it is classically conditioned by being paired with food, turning it into a conditioned stimulus and later a secondary reinforcer.
Step-by-step explanation:
Before being paired with food, the clicker used in operant learning is initially nothing more than a neutral stimulus. It does not elicit any particular response from the learner. However, through the process of classical conditioning, the clicker becomes associated with an unconditioned stimulus like food, which automatically elicits a response (the unconditioned response). Over time, the clicker, once a neutral stimulus, becomes a conditioned stimulus, triggering a conditioned response similar to that elicited by the unconditioned stimulus. After this association is well established, the clicker can then serve as a secondary reinforcer in operant conditioning, where it is used to reinforce a desired behavior without serving as an immediate reward itself.