Dr. meyer is known for his difficult pop quizzes. immediately before he springs a pop quiz on his students, he typically goes to the classroom door and closes it. students soon learn to anticipate a pop quiz whenever dr. meyer closes the classroom door. closing the door has become a(n)

stimulus

The students reaction is explained by the theory of classical conditioning first coined by Ivan Pavlov. The students are conditioned to associate the doer closing with the pop quiz and respond accordingly. Pavlov used dogs and their response to ringing a bell every time their food was served, after a some conditioning the dogs would salivate at the sound of the bell regardless of whether or not food was present. The bell was the stimulus.