<P> A neutral stimulus is a stimulus which initially produces no specific response other than focusing attention . In classical conditioning, when used together with an unconditioned stimulus, the neutral stimulus becomes a conditioned stimulus . With repeated presentations of both the neutral stimulus and the unconditioned stimulus, the neutral stimulus will elicit a response as well, known as a conditioned response . Once the neutral stimulus elicits a conditioned response, the neutral stimulus becomes known as a conditioned stimulus . The conditioned response is the same as the unconditioned response, but occurs in the presence of the conditioned stimulus rather than the unconditioned stimulus . </P> <P> Ivan Pavlov conducted multiple experiments investigating digestion in dogs in which neutral, unconditioned, and conditioned stimuli were used . In these experiments, the neutral stimulus was the sound of a bell ringing . This sound was presented to the dogs along with food, which acted as an unconditioned stimulus . The presentation of a neutral stimulus does not result in any particular response, but the presentation of an unconditioned stimulus results in an unconditioned response, which was the dogs salivating in Pavlov's experiments . After conditioning, the bell ringing became a conditioned stimulus . Pavlov later used the sound of a metronome as a neutral stimulus in studies on cerebral cortex activity . </P>

In classical conditioning the term neutral stimulus is used to indicate that a stimulus