According to classical conditioning, the previously neutral stimulus associated with an unconditioned stimulus will become a conditioned stimulus which will trigger a conditioned response after some time.
For example, at first salivation was produced by placing food on the dog's mouth but since the bell was used during the process of calling a dog for food , it's became a previously neutral stimulus . After a while the dog connects a bell with the food (unconditioned stimulus) as the bell becomes a conditioned stimulus it triggers the same response as does the unconditioned stimulus but since this response occurs due to a conditioned stimulus , it is a conditioned response.
