Pavlov's dogs exhibited stimulus discrimination when they

• A. did not demonstrate a conditioned response upon hearing ticking sounds similar to the metronome.
• B. stopped experiencing the conditioned response in the absence of the unconditioned stimulus.
• C. salivated at the sound of the metronome after a few weeks of not hearing it.
• D. initially began salivating to the metronome when presented with food.

Answer: (A)