Final answer:
In Pavlov's conditioning experiment, the sound of a bell became associated with food, causing dogs to salivate when they heard the bell, even without the presence of food. This demonstrated the principle of classical conditioning and the conditioned response of salivation stimulated by a previously neutral stimulus.
Step-by-step explanation:
In the famous conditioning experiment conducted by Ivan Pavlov, he demonstrated how classical conditioning could be used to elicit a certain response from dogs using a stimulus that ordinarily would not produce such a response. In this case, the dogs were conditioned to start drooling, or salivate, in response to the sound of a bell. This phenomenon occurred because the sound of the bell was consistently paired with the presentation of food, which naturally stimulated salivation. Over time, the dogs learned to associate the bell with food, and thus the bell (a conditioned stimulus) alone was enough to trigger the response of salivation (now a conditioned response), even when food was not present.
This type of learning, which Pavlov initially called 'psychic secretions' before later defining as conditioned responses, was integral in showing how environmental cues could trigger certain responses in an organism. The experiments by Pavlov paved the way for further research into behavioral psychology and the understanding of conditioned reflexes and responses within the nervous system's role in digestion and other physiological processes.