Final answer:
In classical conditioning, the unconditioned stimulus automatically elicits a reaction. It is something that naturally causes a response without any prior learning.
Step-by-step explanation:
In classical conditioning, the unconditioned stimulus is the component that automatically elicits a reaction. This stimulus is something that naturally causes a response without any prior learning.
For example, in Pavlov's experiment with dogs, the food was the unconditioned stimulus. When the dogs saw or smelled the food, they naturally salivated without any conditioning. On the other hand, the conditioned stimulus is a previously neutral stimulus that, through association with the unconditioned stimulus, elicits a conditioned response.