70 Scientific American, February 2022
H
ow much time do you spend doing research before you make
a big decision? The answer for many of us, it turns out, is hardly any.
Before buying a car, for instance, most people make two or fewer trips
to a dealership. And when picking a doctor, many individuals simply
use recommendations from friends and family rather than consulting
medical professionals or sources such as health-care Web sites or arti-
cles on good physicians, according to an analysis published in the jour-
nal Health Services Research.
Carmen Sanchez is an assistant professor at the University
of Illinois at Urbana-Champaign’s Gies College of Business.
She studies the development of misbeliefs, decision-making
and overconfidence.
We are not necessarily conserving our mental
resources to spend them on even weightier decisions.
One in five Americans spends more time planning
their upcoming vacation than they do on their finan-
cial future. There are people who go over every detail
exhaustively before making a choice, and it is cer-
tainly possible to overthink things. But a fair number
of individuals are quick to jump to conclusions. Psy-
chologists call this way of thinking a cognitive bias,
a tendency toward a specific mental mistake. In this
case, the error is making a call based on the sparsest
of evidence.
In our own research, we have found that hasty
judgments are often just one part of larger error-
prone patterns in behavior and thinking. These pat-
terns have costs. People who tend to make such jumps
in their reasoning often choose a bet in which they
have low chances of winning instead of one where
their chances are much better.
To study jumping, we examined decision-making
patterns among more than 600 people from the gen-
eral population. Because much of the work on this
type of bias comes from studies of schizophrenia
( jumping to conclusions is common among people
with the condition), we borrowed a thinking game
used in that area of research.
In this game, players encountered someone who
was fishing from one of two lakes: in one lake, most
of the fish were red; in the other, most were gray. The
fisher would catch one fish at a time and stop only
when players thought they could say which lake was
being fished. Some players had to see many fish
before making a decision. Others—the jumpers—
stopped after only one or two.
We also asked participants questions to learn more
about their thought patterns. We found that the fewer
fish a player waited to see, the more errors that indi-
vidual made in other types of beliefs, reasoning
and decisions.
For instance, the earlier people jumped, the more
likely they were to endorse conspiracy theories, such
as the idea that the Apollo moon landings had been
faked. Such individuals were also more likely to
believe in paranormal phenomena and medical
myths, such as the idea that health officials are
actively hiding a link between cell phones and cancer.
Jumpers made more errors than nonjumpers on
problems that require thoughtful analysis. Consider
this brainteaser: “A baseball bat and ball cost $1.10
together. The bat costs $1 more than the ball. How
much does the ball cost?” Many respondents leaped
to the conclusion of 10 cents, but a little thought
David Dunning is a social psychologist and a professor of psych-
ology at the University of Michigan. His research focuses on
the psychology of human misbelief, particularly false beliefs people
hold about themselves.
