Dr. higgs exposes rats to a vanilla scent prior to receiving a food pellet in the left corner of their cage, but provides no food after exposure to a lemon scent. after several trials, upon smelling a vanilla scent, the rats wait at the far left corner of the cage regardless of whether a food pellet is present. however, they do not wait in the far left corner when exposed to the lemon scent. what is the unconditioned stimulus in the experiment?

food pellet

Explanation:

Unconditioned stimulation is a stimulus that causes an automatic and natural response to a specific situation. In the case of the situation shown in the question, the unconditioned stimulus is the food pellet, because the rats when they smelled vanilla knew they would get a food pellet in the left corner of the cage, so when the rats felt the vanilla smell automatically shifted to the left corner of the cage, even if they didn't receive the food pellet.