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Researchers Identify Cognitive Process That Contributes To Gambling Behavior

June 4, 1997
American Psychological Asssociation
"Selective Hyposthesis Testing" -- the failure to consider more than one possible outcome when making decisions -- has been identified as one of the thinking processes that results in billions in gambling losses annually.

Date: June 2, 1997
Contact: Doug Fizel
Public Affairs Office (202) 336-5706 (email)


Also Suggest Strategy for Counteracting It That Could Be Useful For Both Treatment and Prevention of Problem Gambling

WASHINGTON -- Gambling has always been a big business and as
more states adopt lotteries and permit casino gambling it gets even
bigger every year. From 1993 to 1994, the number of casino visits
in the United States rose 35 percent to 125 million and those
casino visitors left behind $16.5 billion in losses, more than
twice as much as they lost in 1990. But if gambling is, overall,
a losing proposition for the gambler, why do so many people do it?

Over the years, psychological researchers have identified
several thinking processes that contribute to gambling behavior. These include biased evaluations of past gambling results
(explaining away losses and viewing wins as evidence of gambling
ability), the illusion of control (overestimating the influence one
wields over outcomes and the probability of personal success) and
the "gambler's fallacy" (the mistaken belief that over time,
chance-determined outcomes will even out).

In the June issue of the American Psychological Association's
(APA) journal Experimental Psychology: Applied, researchers from
Central Michigan University and the University of Utah add another
cognitive process to that list: selective hypothesis testing, that
is, considering only one possible outcome when making decisions.

The researchers conducted a series of three experiments, in
the first of which participants were asked to estimate the
probability that a specific National Basketball Association team
(one of four) would win the NBA championship and explain how. In
the second experiment they were also asked to estimate the
probability that a specific NBA team beat the point spread in an
earlier game. In the third they were asked to estimate the
probability that an NCAA basketball team (one of four) had won a
computer-simulated playoff. In each experiment, participants were
invited to place bets on the team they thought would win, had
beaten the point spread or had won.

In each experiment participants who focused (as instructed) on
a single team (as opposed to estimating the probability of winning
for all four teams they were considering) consistently
overestimated the probability of that team winning. In addition,
study participants who overestimated that probability were more
likely to place bets and larger bets than those who were not
focused on a single team.

This overestimation of probability, the authors say, "could
influence gambling decisions in any domain in which the potential
gambler may focus on one possible outcome to the exclusion of
others. Thus the blackjack player may be particularly interested
in the likelihood of receiving a 10 after her or his first two
cards sum to 11, the poker player may be particularly interested in
the probability of making a straight on her or his next card, and
the sports gambler may be particularly interested in the likelihood
that the home team may win the league championship."

But, the authors note, selective hypothesis testing is
avoidable. In one of the experiments, some participants (the
control group) had to estimate the probability of each of four
teams winning a computer-simulated championship. Under that
condition, the participants overestimated the probability of
winning for all four teams, indicating that they may have
considered each team a viable contender. But these participants
were less likely to gamble than those who had focused on only one
team. "By encouraging potential gamblers to consider a wide number
of potential outcomes, the appeal of any specific outcome is
lessened and the likelihood that a bet will be placed is reduced,"
the authors write. "Thus, this specific cognitive strategy may
counteract the influence of the selective hypothesis-testing

Not only might this strategy be useful in the treatment of
problem gamblers, the authors suggest it might be useful in
preventing gambling problems from developing. Training in abstract
reasoning skills in secondary schools or college courses "could
include a specific component that addresses the necessity of
considering numerous potential outcomes when attempting to predict
future events. This research suggests that such training could be
relatively general in nature and still be readily applied by
students to gambling and other risky choice situations."

Article: "The Effects of Selective Hypothesis Testing on
Gambling," by Bryan Gibson, Ph.D., Central Michigan University, and
David M. Sanbonmatsu, Ph.D., and Steven S. Posavac, Ph.D.,
University of Utah, in the Journal of Experimental Psychology:
Applied, Vol. 3 No. 2.

(Full text available from the APA Public Affairs Office.)

Bryan Gibson, Ph.D. can be reached at (517) 774-4404 or at

The American Psychological Association (APA), in Washington,
DC, is the largest scientific and professional organization
representing psychology in the United States and is the world's
largest association of psychologists. APA's membership includes
more than 151,000 researchers, educators, clinicians, consultants
and students. Through its divisions in 50 subfields of psychology
and affiliations with 58 state, territorial and Canadian provincial
associations, APA works to advance psychology as a science, as a
profession and as a means of promoting human welfare.

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American Psychological Asssociation. "Researchers Identify Cognitive Process That Contributes To Gambling Behavior." ScienceDaily. ScienceDaily, 4 June 1997. <>.
American Psychological Asssociation. (1997, June 4). Researchers Identify Cognitive Process That Contributes To Gambling Behavior. ScienceDaily. Retrieved August 29, 2016 from
American Psychological Asssociation. "Researchers Identify Cognitive Process That Contributes To Gambling Behavior." ScienceDaily. (accessed August 29, 2016).