Conditioned Stimulus

What is a Conditioned Stimulus?

In classical conditioning, a conditioned stimulus (CS) is a previously neutral stimulus that has been associated with an unconditioned stimulus. Here, neutral means it does not initially elicit the conditioned response being studied; it may elicit other responses.

A tone that comes to elicit salivation through its relationship with food illustrates a conditioned stimulus. Food is the unconditioned stimulus; salivation elicited by the learned tone is the conditioned response. The stimulus is the signal, while the response is what the organism does. It is contrasted with an unconditioned stimulus, which is a stimulus that naturally elicits a response without any previous conditioning.

Source: Pavlovian conditioning: It is not what you think it is.