Invitation to Psychology

316 Chapter 9 Learning and Conditioning

2012). But behaviorists emphasize conditioning:

A doctor’s white coat, the doctor’s office, and pills

or injections all become conditioned stimuli for re-

lief from symptoms because these stimuli have been

associated in the past with real drugs (Ader, 2000).

The real drugs are the unconditioned stimuli, and

the relief they bring is the unconditioned response.

Placebos acquire the ability to elicit similar reac-

tions, thereby becoming conditioned stimuli.

The expectancy explanation of placebo ef-

fects and the classical-conditioning explanation

are not mutually exclusive (Kirsch, 2004; Stewart-

Williams & Podd, 2004). As we saw previously,

many researchers now accept the view that clas-

sical conditioning itself involves the expectation

that the CS will be followed by the US. Thus, at

least some classically conditioned placebo effects

may involve the patient’s expectations. In fact, the

patient’s previous conditioning history may be

what created those expectations to begin with.

Some cancer patients also acquire a classically

conditioned anxiety response to anything associated

with their chemotherapy (Jacobsen et al., 1995).

Conversely, patients may have reduced pain and anxi-

ety when they receive placebos, pills and injections that

have no active ingredients or treatments that have no

direct physical effect on the problem. Placebos can

be amazingly powerful, especially when they take the

form of an injection, a large pill, or a pill with a brand

name (Benedetti & Levi-Montalcini, 2001). Placebos

can actually act on the same neural pathways in

the brain that real medicines do (Price, Finniss, &

Benedetti, 2008; see also Chapter 6).

Why do placebos work? Cognitive psycholo-

gists emphasize the role of expectations, at least in

humans: Expectations of getting better may reduce

anxiety, and that reduction may have a positive ef-

fect on the immune system. Such expectations may

also cause patients to act in ways that produce the

outcome they hope for (Michael, Garry, & Kirsch,

Neutral

stimulus

CS

CR

US

UR (nausea)

US

UR

CLINIC CLINIC

Recite & Review

Recite: Say aloud everything you know about the classical conditionig of positive emotions, pho-

bias, and tastes; counterconditioning; conditioned reactions to medical treatments; and behavioral

explanations of placebo effects.

Review: Next, read this section again and notice anything that you didn’t catch the first time.

Now take this Quick Quiz:

A. See whether you can supply the correct term to describe the outcome in each of these

situations.

1. After Jeff learns to fear spiders, he also responds with fear to ants, beetles, and other
   crawling bugs.


2. Little Erin is afraid of the bath, so her father puts just a little water in the tub and gives her a
   lollipop to suck on while she is being washed. Soon Erin loses her fear of the bath.


3. A factory worker’s mouth waters whenever a noontime bell signals the beginning of his
   lunch break. One day, the bell goes haywire and rings every half hour. By the end of the
   day, the worker has stopped salivating to the bell.
   B. A boy who gets weekly allergy shots starts to feel anxious as soon as he enters the doctor’s
   waiting room. What is the behavioral explanation?
   Answers:

Study and Review at MyPsychLab

The sight and smells of the waiting room have B. extinction3. counterconditioning2. stimulus generalization1. A.

become conditioned stimuli for the anxiety and discomfort provoked by the shots.