How is classical conditioning different from instrumental conditioning?

Classical and instrumental conditioning are both forms of associative learning, but they differ significantly in their experimental procedures and the role of the learner's behavior.12

Classical Conditioning

Pioneered by Ivan Pavlov, this process involves pairing a neutral stimulus (such as a metronome) with an unconditioned stimulus (such as food) that naturally elicits a response. Over time, the neutral stimulus becomes a conditional stimulus, capable of triggering a conditional response on its own. In this technique, the reinforcement (food) is provided regardless of the animal's behavior.123

Instrumental Conditioning

Also known as operant conditioning, this method—developed by researchers like Edward L. Thorndike and B.F. Skinner—requires the learner to perform a specific action to receive a reward or avoid a negative stimulus. Here, reinforcement is contingent upon the organism executing a predesignated behavioral act. While classical conditioning is often associated with involuntary responses, instrumental conditioning typically involves voluntary behaviors that the animal learns to repeat because they are "instrumental" in obtaining a desired outcome.123