Pavlov was interested in the sources of salivation in dogs. He developed a way to measure salivation and found that different foods elicited different levels of salivation. However, he noticed that the dogs would also salivate when he or his assistant entered the room. Through experiments using a metronome and food, he discovered that a neutral stimulus like the metronome could elicit salivation after being paired with food enough times. Pavlov concluded that reflexes can be conditioned to respond to new stimuli, laying the foundation for his theory of classical conditioning.
