In classical conditioning, a conditioned stimulus (CS) is a previously neutral stimulus that has been associated with an unconditioned stimulus. A neutral stimulus is a stimulus that does not elicit a response on its own, but that becomes able to elicit a response through classical conditioning. For example, in Pavlov’s experiment with dogs, the bell was the conditioned stimulus because it did not initially elicit a salivatory response in the dogs, but became able to do so after being paired with the food (the unconditioned stimulus). A conditioned stimulus is a stimulus that has been associated with an unconditioned stimulus through classical conditioning. It is contrasted with an unconditioned stimulus, which is a stimulus that naturally elicits a response without any previous conditioning.
