Range of Pavlovian Conditioning

Pavlovian phenomena have been demonstrated with different kinds of organisms
and a wide variety of stimuli and responses far beyond those studied
by Pavlov. Stimuli that precede such unconditioned stimuli as sudden loud
noises (leading to rapid heart rate), a puff of air delivered to the eye (evoking
blinking), or a large temperature increase (eliciting sweating) may become
conditioned stimuli, capable of eliciting conditioned responses on
their own. The idea of second-order (higher-order) conditioning is profoundly
important because it suggests how rewards such as money or words
of praise are established apart from primary (biologically necessary) rewards,
such as food and water. It also may, in part, explain the power of films,
plays, novels, and advertisements to evoke strong emotion in the absence
of direct experience with primary (unconditioned) stimuli. Studies concerned with conditioned emotional reactions (CER), especially fear and
anxiety in people—a subject much more complex than simple reflexes—
have been of special interest to researchers and therapists for many years.