Jim goes to the dentist to have a cavity filled. He hears the shrill sound of the drill, his muscles tense and he experiences pain as the dentist works on his teeth. After that experience, whenever Jim hears the sound of the drill, his muscles tense and he becomes anxious. What is the conditioned stimulus?

Sound of the drill

Explanation:

The Conditioned stimulus is the occurrence that has been associated with the Unconditioned stimulus to bring out a conditioned reaction.

The Unconditioned stimulus in this scenario is the pain that was experienced when the dentist worked on the teeth. This has now been associated with the sound of a drill such that whenever Jill hears this sound, he associates it with Pain and becomes anxious.