ABSTRACT
50Ivan Pavlov developed classical conditioning procedures to study animals under conditions where an event can be predicted but not controlled. Anticipation, blank trials, and sign-tracking procedures are used to directly measure the timing, magnitude, and frequency of conditioned predictive responses. The conditioned suppression procedure indirectly measures the strength of a predictive stimulus from the extent to which it reduces operant responding.
Pavlov demonstrated that if one stimulus preceded another, a new response would be acquired to the first stimulus. He also demonstrated that if the second stimulus stopped following the first, the learned response would also stop, which he named extinction. These phenomena fulfill the operational definition of learning as behavior changes resulting from experience.
Pavlov demonstrated that animals not only could learn that one event would be followed by another (i.e., excitatory learning), but also that one event would not be followed by another (i.e., inhibitory learning). The sequencing, timing, intensity, and scheduling of stimulus events were found to influence the course of learning and strength of the learned response. Other phenomena described, included spontaneous recovery, external inhibition, disinhibition, renewal, stimulus generalization, discrimination, and occasion-setting.
