Invitation to Psychology

Chapter 7 Thinking and Intelligence 239

“noise” in the information. But it also leads us to

see meaningful patterns even when they do not

exist. For example, many people with arthritis

think that their symptoms follow a pattern dic-

tated by the weather. They suffer more, they say,

when the barometric pressure changes or when

the weather is damp or humid. Yet when research-

ers followed 18 arthritis patients for 15 months,

no association whatsoever emerged between

weather conditions and the patients’ self-reported

pain levels, their ability to function in daily life,

or a doctor’s evaluation of their joint tenderness

(Redelmeier & Tversky, 1996). Of course, because

of the confirmation bias, the patients refused to

believe the results.

The Need for Cognitive

Consistency LO 7.8, LO 7.9, LO 7.10

Mental sets and the confirmation bias cause us

to avoid evidence that contradicts our beliefs.

But what happens when disconfirming evi-

dence finally smacks us in the face, and we can-

not ignore or discount it any longer? Consider

doomsday predictions, which have been made

throughout history. When these predictions fail,

how come we never hear believers say, “Boy, what

a fool I was”?

According to the theory of cognitive disso-

nance, people will resolve such conflicts in predict-

able, though not always obvious, ways (Festinger,

1957 ; see Chapter 10). Dissonance, the opposite

of consistency (consonance), is a state of tension

that occurs when you hold either two cognitions

(beliefs, thoughts, attitudes) that are psychologi-

cally inconsistent with one another or a belief

that is incongruent with your behavior. This ten-

sion is psychologically uncomfortable, so you will

be motivated to reduce it. You may do this by

cognitive dissonance

A state of tension that

occurs when a person

holds two cognitions

that are psychologically

inconsistent, or when a

person’s belief is incon-

gruent with his or her

behavior.

biased or unimportant. Police officers who are
convinced of a suspect’s guilt take anything the
suspect says or does as evidence that confirms
it, including the suspect’s claims of innocence
(Davis, 2010). Many jury members, instead of
weighing possible verdicts against the evidence,
quickly construct a story about what happened at
the start of the trial and then consider only the
evidence that supports it (Kuhn, Weinstock, &
Flaton, 1994). We bet you can see the confirma-
tion bias in your own reactions to what you are
learning in psychology. In thinking critically,
most of us apply a double standard; we think
most critically about results we dislike. That is
why the scientific method can be so difficult: It
forces us to consider evidence that disconfirms
our beliefs.

Mental Sets

Another barrier to rational thinking is the devel-
opment of a mental set, a tendency to try to solve
new problems by using the same heuristics, strate-
gies, and rules that worked in the past on similar
problems. Mental sets make human learning and
problem solving efficient; because of them, we
do not have to keep reinventing the wheel. But
mental sets are not helpful when a problem calls
for fresh insights and methods. They cause us
to cling rigidly to the same old assumptions and
approaches, blinding us to better or more rapid
solutions.
One general mental set is the tendency to find
patterns in events or data (“when it’s hot, earth-
quakes occur”; “I see signs of a conspiracy”). This
tendency helps us understand and exert some con-
trol over what happens in our lives, and indeed the
first step in forensic and scientific investigations of
a problem is to find meaningful patterns despite

mental set A ten-

dency to solve problems

using procedures that

worked before on similar

problems.

Get Involved! Connect the Dots

Copy this figure, and try to connect the dots by using no more than four straight lines without lifting your

pencil or pen. A line must pass through each point. Can you do it?

Most people have difficulty with this problem because they have a mental set to interpret the arrangement

of dots as a square. They then assume that they can’t extend a line beyond the apparent boundaries of

the square. Now that you know this, you might try again if you haven’t yet solved the puzzle. Some solu-

tions are given at the end of this chapter.