Explanation:In classical conditioning, learning occurs involuntary because we respond to stimuli automatically and naturally. We start to associate certain stimuli with each other and the first encountered stimulus is the one that triggers natural and automatic response from us, and this stimuli is referred to as unconditioned stimulus and it will yield an automatic response that we have not learned before. Like when someone soothes you with a hug after a stressful day , you feel that arousal which occurs automatic and it is an involuntary response.
In operant conditioning we actual embark on a journey to learn such as observational learning in which we study others behavior so that we can imitate it.