Professor Kraig is known for his difficult quizzes, which automatically make the students anxious. Immediately before each quiz, he always turns off the projector. Students soon notice that they start to feel anxious when Professor Kraig turns off the projector. In terms of classical conditioning, Professor Kraig turning off the projector is a(n):

conditiond stimulus

Explanation:¨Professor Kariag is turning off the projector to signal that there will be a quiz, so he is making it the conditioned stimulus.

Students experienced it previously so many times that they became aware that the signal means that a hard quiz was to come thereafter.

The act of just turning off the projector could have occurred at random , and that originally was just another neutral stimulus. After a neutral stimulus is paired with the doing of a quiz, a conditioned response is formed as well:

Students begin already to feel anxious.