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Psychological Science
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DOI: 10.1177/0956797612438733
2012 23: 1123 originally published online 28 August 2012Psychological Science
Tali Sharot, Stephen M. Fleming, Xiaoyu Yu, Raphael Koster and Raymond J. Dolan
Is Choice-Induced Preference Change Long Lasting?
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DOI: 10.1177/0956797612438733
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The idea that choice shapes preferences has implications for
many domains, from marketing to health and relationships
(Ariely & Norton, 2008). After choosing between options,
including presidential candidates (Beasley & Joslyn, 2001),
household objects (Brehm, 1956), and medical conditions
(Sharot, Shiner, & Dolan, 2010), people tend to value the cho-
sen alternative more and the rejected alternative less. One
explanation for this effect is that selecting between two simi-
larly valued options creates dissonance that is resolved by
reevaluating the options after the selection is made (Festinger,
1957; for an alternative account, see Bem, 1967, 1972; Sharot,
De Martino, & Dolan, 2009).
An unresolved question concerns how stable these choice-
induced changes are. Although numerous studies have demon-
strated postchoice changes in preferences (for a review, see
Harmon-Jones & Mills, 1999), all of these studies have exam-
ined such changes shortly after a decision is made (with one
exception noted in the following paragraph; see Vroom &
Deci, 1971). It is therefore difficult to answer the question of
whether choice-induced modulations of value are stable and
long lasting or evanescent, fading away quickly after a deci-
sion is made. If the latter is true, it could be argued that the
phenomenon has attracted more attention than it deserves.
Studies examining other forms of cognitive dissonance
that are not triggered by choice have often found long-term
behavioral change (Freedman, 1965; but see Aronson &
Carlsmith, 1963; for a review, see Walster & Berscheid, 1968).
For example, Higgins, Rhodewalt, and Zanna (1979) reported
attitudinal changes that persisted for 2 weeks following coun-
terattitudinal behavior. However, some researchers have sug-
gested that the choice-induced reevaluation of options is a
fleeting phenomenon. Recently, it has been shown that post-
choice changes in preference can be eliminated simply by
washing one’s hands (Lee & Schwarz, 2010). The preferred
explanation for this finding is that physical cleanliness serves
as a metaphor for psychological purity and removes choice-
evoked cognitive dissonance, obviating the need for reevalua-
tion. The implication here is that postchoice changes in
preference are highly unstable and might be affected by appar-
ently minor everyday behaviors. Moreover, experiencing a
selected option reduces its choice-induced overvaluation,
Corresponding Author:
Tali Sharot, University College London, 26 Bedford Way, London WC1H 0AP,
England
E-mail: t.sharot@ucl.ac.uk
Is Choice-Induced Preference Change
Long Lasting?
Tali Sharot
1
, Stephen M. Fleming
2,3
, Xiaoyu Yu
4
,
Raphael Koster
4,5
, and Raymond J. Dolan
4
1
Department of Cognitive, Perceptual and Brain Sciences, University College London;
2
Centre for
Neuroscience, New York University;
3
Department of Experimental Psychology, University of
Oxford;
4
Wellcome Trust Centre for Neuroimaging, Institute of Neurology, University College
London; and
5
Institute of Cognitive Neuroscience, University College London
Abstract
The idea that decisions alter preferences has had a considerable influence on the field of psychology and underpins cognitive
dissonance theory. Yet it is unknown whether choice-induced changes in preferences are long lasting or are transient
manifestations seen in the immediate aftermath of decisions. In the research reported here, we investigated whether these
changes in preferences are fleeting or stable. Participants rated vacation destinations before making hypothetical choices
between destinations, immediately afterward, and 2.5 to 3 years later. We found that choices altered preferences both
immediately after being made and after the delay. These changes could not be accounted for by participants’ preexisting
preferences, and they occurred only when participants made the choices themselves. Our findings provide evidence that
making a decision can lead to enduring change in preferences.
Keywords
decision making, cognitive dissonance, preferences, social cognition
Received 7/18/11; Revision accepted 1/11/12
Research Article
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1124 Sharot et al.
despite persistent devaluation of the rejected option (Vroom &
Deci, 1971). This finding suggests that when people sample
their selected option, the experience itself alters their prefer-
ence, diluting the impact of their initial decision.
Thus, there is little consensus as to the temporal profile of
choice-induced change in preference. In the research reported
here, we examined whether making a hypothetical choice can
induce changes in preference that are stable over long inter-
vals. We asked participants to rate vacation destinations, make
hypothetical choices between destinations, and then rate these
destinations again immediately after the choices and 2.5 to
3 years later. To test whether the long-term choice-induced
reevaluation of options requires a sense of agency over the
decision, we examined preferences both when the participants
made decisions themselves and when a computer made deci-
sions for them.
Critically, we controlled for the possibility that any post-
choice changes in ratings were merely reflections of partici-
pants’ preexisting preferences rather than changes induced by
the decisions themselves (Chen & Risen, 2010). People’s pref-
erences are subject to rating noise, but as participants gain
experience in using a rating scale, their ratings become less
noisy. Consequently, postchoice shifts in ratings might simply
reflect participants’ true initial preferences (which can be pre-
dicted by participants’ choices) rather than changes in prefer-
ences induced by choice.
To examine whether changes in preferences could be
explained solely by preexisting preferences, we adopted a par-
adigm used recently by Izuma et al. (2010). Participants rated
all stimuli and then either made free choices between stimuli
(experimental condition) or had decisions made for them by a
computer (control condition). They then rated all stimuli again
immediately after the decision-making task and 2.5 to 3 years
later. In the control condition, they then freely chose between
stimuli. The inclusion of this task made the control condition
analogous to the “rate rate choose” condition used by Chen
and Risen (2010). Because participants in the control condi-
tion had not been responsible for the first set of choices during
the computer-choice trials, their final choices provide infor-
mation about their true preferences and are informative about
the extent of rating change that can be expected in the absence
of choice.
Finally, according to cognitive dissonance theory, choice-
induced changes in preferences should occur when people
make difficult decisions between two similarly desirable alter-
natives. Such changes in preferences presumably arise because
making a difficult choice engenders psychological discomfort,
given that the decision conflicts with the desirable aspects of
the rejected alternative and with the undesirable aspects of the
selected alternative (Festinger, 1957). According to this the-
ory, psychological tension is reduced through a reevaluation of
the options after the choice is made (for an alternative account,
see Bem, 1967). To test whether long-term choice-induced
changes in preferences are specific to cases involving difficult
decisions, we compared the change between prechoice and
postchoice ratings for cases in which choices were between
equally rated destinations (difficult choices) with the change
in ratings for cases in which choices were between unequally
rated destinations (easy choices).
Method
Participants
The study comprised two phases. Forty-five University Col-
lege London undergraduates (age range: 19–35 years; 7 males,
38 females) took part in Phase 1. One participant began the
experiment but did not complete it. Five participants were
eliminated because they failed to respond on an excessive
number of trials (> 25%; this level of performance is an a pri-
ori cutoff used in previous research; Sharot, De Martino, &
Dolan, 2009; Sharot, Shiner, Brown, Fan, & Dolan, 2009;
Sharot, Shiner, & Dolan, 2010; Sharot, Velasquez, & Dolan,
2010). Our final sample comprised 39 participants (experi-
mental condition: 19 participants; control condition: 20 par-
ticipants). (Partial data for control participants’ immediate
postchoice ratings have been published previously, in Sharot,
Velasquez, & Dolan, 2010). Between 2.5 and 3 years later, 18
of the participants completed Phase 2 of the study (experimen-
tal condition: 9 participants; control condition: 9 participants).
All participants gave informed consent and were compensated
for their participation.
Stimuli
Stimuli consisted of 80 names of vacation destinations adapted
from a previous study (Sharot, De Martino, & Dolan, 2009;
Sharot, Shiner, et al., 2009; Sharot, Shiner, & Dolan, 2010;
Sharot, Velasquez, & Dolan, 2010). The order of stimulus pre-
sentation was random.
Conditions
Experimental condition. In Phase 1, participants in the
experimental condition completed prechoice ratings, a free-
choice decision task, and immediate postchoice ratings a few
minutes after the decision task. Phase 2 was conducted approx-
imately 3 years after Phase 1 and consisted of delayed post-
choice ratings. Five participants who were no longer living in
London completed the delayed postchoice ratings from home
via e-mail.
Control condition. In Phase 1, participants in the control con-
dition completed prechoice ratings, a computer-choice decision
task, and immediate postchoice ratings a few minutes after the
decision task. Phase 2 was conducted between 2.5 and 3 years
after Phase 1 and consisted of two stages. In the first stage (2.5
years after Phase 1), participants made delayed postchoice rat-
ings. In the second stage (approximately 6 months later), par-
ticipants completed a postexperimental free-choice decision
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Is Choice-Induced Preference Change Long Lasting? 1125
task, in which they were asked to choose between vacation des-
tinations that had been presented during the computer-choice
task in Phase 1. Because participants in this condition were not
responsible for the decisions made during the computer-choice
task, responses in the free-choice task provided information
about these participants’ true underlying preferences and about
the extent to which ratings can be expected to change in the
absence of choice. This task design was adopted from a recent
study (Izuma et al., 2010) and was analogous to the design used
by Chen and Risen (2010). Four participants who were no lon-
ger living in London completed the delayed postchoice ratings
from home via e-mail.
Ratings of vacation destinations
All vacation-destination ratings (prechoice, immediate post-
choice, and delayed postchoice) were carried out in an identi-
cal manner. The rating task consisted of eighty 11-s trials. On
each trial, the name of a vacation destination appeared on a
computer screen for 6 s. Participants were instructed to imag-
ine themselves spending the next year’s vacation at that loca-
tion. They then had 2 s to rate how happy they would be if they
were to vacation at that location (1 = unhappy, 2 = a bit
unhappy, 3 = neutral, 4 = happy, 5 = very happy, 6 = extremely
happy). Ratings were made using the computer keyboard.
After each rating was made, a fixation cross was presented for
3 s. If a participant did not respond on a trial, data for that trial
were excluded from the final analysis.
Decision task
Free choice. On each trial of the free-choice task, two names of
vacation destinations participants had rated earlier appeared
side by side on the computer screen for 4 s. The word “CHOOSE”
then appeared above the two options for 2 additional seconds.
Participants were instructed to indicate which location they
would hypothetically prefer to vacation at the next year by
pressing one of two buttons when the word “CHOOSE”
appeared. After a response had been made, an asterisk appeared
next to the name of the chosen location. Finally, a fixation cross
was presented for 3 s.
As in previous work (Sharot, De Martino, & Dolan, 2009;
Sharot, Shiner, et al., 2009; Sharot, Shiner, & Dolan, 2010;
Sharot, Velasquez, & Dolan, 2010), stimulus pairs were deter-
mined using a custom routine written in MATLAB (The Math-
Works, Natick, MA). Stimuli on 70% of the trials were pairs of
vacation destinations the participant had rated equally in the
prechoice rating task (difficult-choice trials). On the remaining
30% of trials, stimuli consisted of pairs of vacation destina-
tions that the participant had rated unequally in the prechoice
rating task (easy-choice trials).
Computer choice. In the computer-choice task, participants
were told that the computer would choose which vacation des-
tinations they would vacation at the next year. (Choices were
hypothetical.) On each trial, names of two vacation destina-
tions participants had rated in the prechoice rating task
appeared on-screen for 4 s. The word “CHOOSE” then
appeared above the two options, and an asterisk appeared for
2 s next to the stimulus the computer had randomly chosen. To
ensure that the participants attended to the task and to equate
the action requirements in the free-choice and computer-
choice decision tasks, we instructed participants to indicate
which stimulus the computer had chosen for them on each
trial by pressing one of two buttons (corresponding to the
option on the right and the option on the left) once they saw
the asterisk. A fixation cross was then presented for 3 s. Pairs
of vacation destinations were determined as they were in the
free-choice task.
Data analysis
Creating difference scores. Mean-corrected scores were
computed as in our previous studies (Sharot, De Martino, &
Dolan, 2009; Sharot, Shiner, et al., 2009; Sharot, Shiner, &
Dolan, 2010; Sharot, Velasquez, & Dolan, 2010). The mean-
corrected score (xi − µ) is the distance of a participant’s rating
of a particular stimulus from the average rating for that partici-
pant and rating session. The mean-corrected score indicates
the value of the stimulus relative to that of all other stimuli in
a particular rating session (prechoice, immediate postchoice,
or delayed postchoice). For each participant, stimulus, and
postchoice phase, we calculated the postchoice shift in prefer-
ence by subtracting the mean-corrected prechoice rating from
the mean-corrected postchoice rating. This procedure created
two difference scores per stimulus: an immediate-change dif-
ference score (immediate-postchoice mean-corrected score
minus prechoice mean-corrected score) and a delayed-change
difference score (delayed-postchoice mean-corrected score
minus prechoice mean-corrected score).
Dividing stimuli into rejected and selected options. For
each participant in the experimental condition, stimuli were
categorized as rejected or selected on the basis of the decisions
the participant had made during the free-choice decision task
that occurred between the two rating tasks in Phase 1.
For each participant in the control condition, stimuli were
categorized as rejected or selected in two ways. First, to exam-
ine whether changes in preferences occurred when decisions
were not made by the participants themselves, we divided
stimuli into the two categories on the basis of whether the
stimuli had been rejected or selected by the computer during
the computer-choice decision task that occurred between the
two rating tasks in Phase 1. Second, to examine whether
changes in preferences could be accounted for by preexisting
preferences (i.e., to examine whether choices simply reflected,
rather than altered, preferences), we divided stimuli into the
two categories on the basis of whether they had been rejected
or selected by participants during the free-choice decision task
that occurred at the end of the study, after all rating tasks.
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1126 Sharot et al.
Statistical analysis. Difference scores were entered into
a mixed linear model with decision task (experimental-
condition free choice, control-condition computer choice,
control-condition free choice), time of postchoice rating
(immediate, delayed), selection status (selected, rejected), and
difficulty of decision (difficult, easy) as fixed effects and par-
ticipants as random effects. This analysis was followed by
separate analyses of variance (ANOVAs) in each condition
and post hoc t tests.
Results
The differences between mean-corrected prechoice and mean-
corrected postchoice ratings for each group and condition are
shown in Figures 1 and 2. Results revealed that choice-induced
changes in preferences are long lasting and contingent on indi-
viduals making the choice themselves. Specifically, entering
difference scores into a mixed linear model revealed the criti-
cal three-way interaction of decision task, difficulty of deci-
sion, and selection status, F(2, 55) = 6.33, p < .005. There was
no main effect of time of postchoice rating, nor any significant
interaction of time of postchoice rating with any other factor.
No other main effects or interactions were significant.
Follow-up ANOVAs for each condition revealed that the
critical three-way interaction was due to a significant interac-
tion between difficulty of decision and selection status in the
experimental condition, F(2, 8) = 23.15, p < .001, η
p
2
= .743,
but not in the control condition (free choice: p = .38; computer
choice: p = .89). The critical interaction between difficulty of
decision and selection status in the experimental condition
was also significant when we examined the data separately for
the immediate ratings, F(1, 18) = 14.78, p < .001, η
p
2
= .45,
and the delayed ratings, F(1, 8) = 21.1, p < .002, η
p
2
= .725.
Follow-up t tests on data for the experimental condition
revealed that this critical two-way interaction was due to a
long-lasting alteration of preferences (i.e., both immediately
after the decision and 3 years later) when difficult decisions
between two equally rated items were made. In particular, rat-
ings for destinations participants had selected in difficult deci-
sions increased—immediate rating condition: t(18) = 5.2, p <
.0001, d = 1.64; delayed rating condition: t(8) = 2.8, p < .025,
d = 1.34. This increase was significantly greater than the non-
significant decrease in ratings of rejected stimuli—immediate
rating condition: t(18) = 5.3, p < .0001, r
2
= .6; delayed rating
condition: t(8) = 3.4, p < .01, r
2
= .59 (Fig. 1). In contrast,
when participants made easy decisions between unequally
rated items, changes in preferences were not observed imme-
diately afterward, but after 3 years, ratings of selected items
decreased, t(8) = 2.9, p < .02, d = 1.38, and ratings of rejected
items increased, t(8) = 2.3, p < .05, d = 0.97 (Fig. 2). These
unpredicted post hoc findings should be interpreted with cau-
tion, given that an ANOVA did not reveal an interaction of
decision task, selection status, and time of postchoice rating.
Follow-up t tests on data for control participants revealed
that their ratings were not affected by choices the computer
had made. However, dividing stimuli into selected and rejected
categories on the basis of the participants’ choices at the end of
the study revealed a significant increase in the immediate
–0.2
–0.1
0.1
0.2
0.3
0.4
Change in Rating
0
Experimental Group
(Free Choice)
Control Group
(Free Choice)
Control Group
(Computer Choice)
Experimental Group
(Free Choice)
Control Group
(Free Choice)
Control Group
(Computer Choice)
Immediate Delay
Selected
Rejected
Fig. 1. Preference changes induced by making difficult choices between two equally rated items. The graph shows the differences
between mean-corrected prechoice ratings and mean-corrected postchoice ratings, separately for selected and rejected vacation
destinations and for immediate and delayed rating conditions. For the experimental condition, vacation destinations were divided
into “selected” and “rejected” categories according to the choices participants had made between the two rating tasks in Phase 1.
For the control condition, vacation destinations were divided into “selected” and “rejected” categories in two ways: according to
the computer’s (random) choices, which were made between the two rating tasks in Phase 1, and according to free choices made by
participants in the free-choice task at the end of the study, after all rating tasks. Error bars represent standard errors of the mean.
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