How did Ivan Pavlov’s work differ from Edward L. Thorndike’s experiments with cats?

The primary difference between the work of Russian physiologist Ivan Pavlov and American psychologist Edward L. Thorndike lies in the type of conditioning they studied and the nature of the responses elicited.12

• Classical Conditioning (Pavlov): Pavlov’s experiments focused on classical conditioning, where subjects develop involuntary, reflexive responses to stimuli. In his classic study, a dog was conditioned to salivate—an involuntary biological reaction—at the sound of a metronome that had been repeatedly associated with the presentation of food.132
• Instrumental Conditioning (Thorndike): Thorndike initiated the study of instrumental conditioning, which involves voluntary behaviors. In his "puzzle box" experiments, a cat had to perform a specific action, such as pressing a lever or pulling a loop, to escape and obtain a food reward. According to his law of effect, the probability of repeating these voluntary behaviors depended on the consequences (the reward of escape and food) that followed them.1245

In short, Pavlov’s work demonstrated how organisms learn involuntary associations, while Thorndike’s work showed how organisms modify voluntary behavior based on the results of their actions.1