Chapter 9 Learning and Conditioning 309sometimes also called Pavlovian or respondent con-
ditioning. Pavlov and his students went on to
show that all sorts of things can become condi-
tioned stimuli for salivation if they are paired
with food: the ticking of a metronome, the musi-
cal tone of a bell, the vibrating sound of a buzzer,
a touch on the leg, even a pinprick or an electric
shock.
Watch the Video The Basics 1: Classical
Conditioning: An Involuntary Response at
MyPsychLabPrinciples of Classical
Conditioning LO 9.2
Classical conditioning occurs in all species, from
one-celled amoebas to Homo sapiens. In the labo-
ratory, many responses besides salivation have
been classically conditioned, including heartbeat,
stomach secretions, blood pressure, alertness,
hunger, and sexual arousal. The optimal interval
between the presentation of the neutral stimulus
and the presentation of the US is often quite
short, sometimes less than a second. Let us look
more closely at some of classical conditioning’s
other important features: extinction, higher-order
conditioning, and stimulus generalization and
discrimination.Extinction. Conditioned responses can persist
for months or years. But if a conditioned stimu-
lus is repeatedly presented without the uncon-
ditioned stimulus, the conditioned response will
weaken and may eventually disappear, a process
known as extinction (see Figure 9.2 on the next
page). Suppose that you train your dog Milo to
salivate to the sound of a bell, but then you ring
the bell every five minutes and do not follow it
with food. Milo will salivate less and less to the
bell and will soon stop salivating altogether; sali-
vation will have been extinguished. Extinction,
however, is not the same as unlearning or for-
getting. If you come back the next day and ring
the bell, Milo may salivate again for a few trials,
although the response will probably be weaker.
The reappearance of the response, called spon-
taneous recovery, explains why completely elimi-
nating a conditioned response often requires
more than one extinction session.
Simulate the Experiment Extinction and
Spontaneous Recovery at MyPsychLabHigher-Order Conditioning. Sometimes a neu-
tral stimulus can become a CS by being paired
with an already established CS, a procedureextinction The weaken-
ing and eventual disap-
pearance of a learned
response; in classical
conditioning, it occurs
when the conditioned
stimulus is no longer
paired with the uncondi-
tioned stimulus.spontaneous recovery
The reappearance of a
learned response after its
apparent extinction.stimulus, Pavlov meant a thing or event that al-
ready produces a certain response without addi-
tional learning. By an unconditioned response, he
meant the response that is produced:
URUSIn Pavlov’s lab, when some neutral stimulus
such as the dish—a stimulus that did not typically
cause the dog to salivate—was regularly paired
with food, the dog learned to associate the dish
and the food. As a result, the dish alone acquired
the power to make the dog salivate:
Neutral
stimulusUSURMore generally, as a neutral stimulus and
US become associated, the neutral stimulus be-
comes a conditioned stimulus (CS). The CS then
has the capacity to elicit a learned or conditioned
response (CR) that is usually similar or related to
the original, unlearned one. In Pavlov’s labora-
tory, the sight of the food dish, which had not
previously elicited salivation, became a CS for
salivation:
CSCRThe procedure by which a neutral stimu-
lus becomes a conditioned stimulus eventually
became known as classical conditioning, and is
conditioned stimulus
(CS) The classical-
conditioning term for an
initially neutral stimulus
that comes to elicit a
conditioned response
after being paired with an
unconditioned stimulus.conditioned response
(CR) The classical-
conditioning term for a
response that is elicited
by a conditioned stimu-
lus; it occurs after the
conditioned stimulus is
paired with an uncondi-
tioned stimulus.classical conditioning
The process by which
a previously neutral
stimulus is paired with
a stimulus that already
elicits a certain response
and, in turn, acquires the
capacity to elicit a similar
or related response. Also
called Pavlovian or re-
spondent conditioning.