Ivan Pavlov was a Russian physiologist best known for his work in classical conditioning, a learning process that occurs through associations between an environmental stimulus and a naturally occurring stimulus. His famous experiments with dogs demonstrated how a neutral stimulus, like the sound of a bell, could elicit a conditioned response, such as salivation, when paired repeatedly with food. This foundational concept is crucial for understanding behaviorist approaches to classroom management, which focus on observable behaviors and the influence of the environment on learning.