Who is best known for his theory of classical conditioning?

Ivan Pavlov is best known for his theory of classical conditioning, which he established through his experiments with dogs. In these experiments, Pavlov discovered that dogs would salivate not only in response to food but also when they heard a bell that had been associated with the presentation of food. This led to the insight that behavior can be modified through the association of stimuli.

Classical conditioning involves a learning process in which a neutral stimulus becomes associated with a meaningful stimulus, thereby eliciting a conditioned response. Pavlov's work laid the groundwork for behaviorism and greatly influenced both psychology and education by highlighting the ways in which behavior can be conditioned through external stimuli. His research demonstrated the importance of empirical observation and experimentation in studying behavior, a cornerstone of psychological science.

The other figures mentioned, while influential in their own rights, focused on different aspects of human behavior and development. Sigmund Freud concentrated on psychoanalysis and the unconscious mind, B.F. Skinner is renowned for his work in operant conditioning and behavior modification, and Jean Piaget studied cognitive development in children. Each of their contributions is significant, but they do not pertain to classical conditioning in the way Pavlov's work does.