How did Ivan Pavlov condition dogs to salivate when they heard a sound?

To condition a dog to salivate in response to a sound, Ivan Pavlov utilized a systematic procedure now known as classical conditioning.12

In his experiments, Pavlov restrained a hungry dog and presented it with an arbitrary stimulus, such as the ticking of a metronome or a buzzer, immediately before delivering food (meat powder).31

The process functioned as follows:
* Unconditioned Stimulus: The food, which naturally and invariably elicits salivation.1
* Unconditioned Response: The dog’s natural salivation in response to the food.1
* Conditioned Stimulus: The sound (e.g., the metronome), which initially does not trigger salivation.1

By consistently pairing the sound with the delivery of food, the dog learned to associate the two events. Eventually, the sound alone became a conditioned stimulus capable of eliciting salivation, which then became a conditioned response. If the sound was presented repeatedly without the food, the response would gradually undergo extinction.14