After establishing a classically conditioned response to a tone, the experimenter then set up a second trial using a new conditioned stimulus, a red light. He repeatedly paired the new conditioned stimulus (the red light) with the conditioned stimulus from the first trial (the tone). This procedure resulted in the conditioned response being elicited by the red light alone (the new conditioned stimulus), even though it had never been paired with the unconditioned stimulus. The experimenter has demonstrated: