Answer:
The answer is conditioned stimulus.
Explanation:
In classical conditioning, a conditioned stimulus (the sound of the door closing) is associated with an unrelated consequence, known as unconditioned stimulus (the pop quizzes). This produces a reaction known as conditioned response.
It's important to recognise that any neutral stimulus can become conditioned. In the example, instead of closing the door, Dr. Meyer could choose to slam his books on the desk. When paired with the quizzes, this would create the same response.
