Pavlov's experiment on dogs shows

In classical conditioning, the conditioned stimulus (which usually does not produce the response), when paired with the unconditioned stimulus (stimulus which usually produces a response), directly produces a response,  The typical example of classical conditioning is Pavlov's experiment.  Normally food produces salivation in a dog. Therefore salivation in response to food is called the unconditioned response and the stimulus, i.e., food is called the unconditioned stimulus. Under normal circumstances, a dog does not salivate at the sound of a bell. However, if the sound of the bell is paired consistently with the presentation of food, the dog begins to salivate to the sound of the bell even if the food is not presented. This learned response, i.e., salivation to a sound of the bell without food, is called conditioned response and the stimulus (sound of a bell) is called a conditioned stimulus. Before conditioning  Unconditioned stimulus (food) → Unconditioned response (salivation)  Unconditioned stimulus (food) + Conditioned stimulus (Bell) → Unconditioned response Q (salivation) After conditioning  Conditioned stimulus (Bell) → Conditioned response (salivation)