What is a neutral stimulus?

A neutral stimulus is defined as a stimulus that initially has no effect on an organism's behavior. In classical conditioning, this type of stimulus can, through learning, become associated with an unconditioned stimulus to eventually elicit a conditioned response. For example, in Pavlov's famous experiment, the sound of a bell was initially a neutral stimulus that did not produce salivation in dogs until it was paired with food (the unconditioned stimulus). After repeated pairings, the bell alone could elicit salivation, demonstrating how a neutral stimulus can become significant through association.

The other descriptions do not accurately capture the essence of a neutral stimulus. A stimulus that always elicits a response is indicative of an unconditioned stimulus rather than a neutral one. A conditioned stimulus is one that has been learned to elicit a response after being paired with an unconditioned stimulus, so it is not simply neutral. An innate trigger for behavioral response refers to unconditioned stimuli, which evoke reflexive responses without prior learning, while a neutral stimulus does not trigger any response initially.