Ego Depletion: Is the Active Self a Limited Resource?
Roy E Baumeister, Ellen Bratslavsky, Mark Muraven, and Dianne M. Tice
Case Western Reserve University
Choice, active response, self-regulation, and other volition may all draw on a common inner resource.
In Experiment 1, people who forced themselves to eat radishes instead of tempting chocolates
subsequently quit faster on unsolvable puzzles than people who had not had to exert self-control
over eating. In Experiment 2, making a meaningful personal choice to perform attitude-relevant
behavior caused a similar decrement in persistence. In Experiment 3, suppressing emotion led to a
subsequent drop in performance of solvable anagrams. In Experiment 4, an initial task requiring
high self-regulationmade people more passive (i.e., more prone to favor the passive-response option).
These results suggest that the self's capacity for active volition is limited and that a range of
seemingly different, unrelated acts share a common resource.
Many crucial functions of the self involve volition: making
choices and decisions, taking responsibility, initiating and inhibiting
behavior, and making plans of action and carrying out
those plans. The self exerts control over itself and over the
external world. To be sure, not all human behavior involves
planful or deliberate control by the self, and, in fact, recent work
has shown that a great deal of human behavior is influenced by
automatic or nonconscious processes (see Bargh, 1994, 1997).
But undoubtedly some portion involves deliberate, conscious,
controlled responses by the self, and that portion may be dispro-'
portionately important to the long-term health, happiness, and
success of the individual. Even if it were shown that 95% of
behavior consisted of lawful, predictable responses to situational
stimuli by automatic processes, psychology could not
afford to ignore the remaining 5%. As an analogy, cars are
probably driven straight ahead at least 95% of the time, but
ignoring the other 5% (such as by building cars without steering
wheels) would seriously compromise the car's ability to reach
most destinations. By the same token, the relatively few active,
controlling choices by the self greatly increase the self's
chances of achieving its goals. And if those few "steering"
choices by the self are important, then so is whatever internal
structure of the self is responsible for it.
In the present investigation we were concerned with this controlling
aspect of the self. Specifically, we tested hypotheses of
ego depletion, as a way of learning about the self's executive
function. The core idea behind ego depletion is that the self's
acts of volition draw on some limited resource, akin to strength
or energy and that, therefore, one act of volition will have a
detrimental impact on subsequent volition. We sought to show
that a preliminary act of self-control in the form of resisting
temptation (Experiment 1) or a preliminary act of choice and
responsibility (Experiment 2) would undermine self-regulation
in a subsequent, unrelated domain, namely persistence at a difficult
and frustrating task. We then sought to verify that the
effects of ego depletion are indeed maladaptive and detrimental
to performance (Experiment 3). Last, we undertook to show
that ego depletion resulting from acts of self-control would
interfere with subsequent decision making by making people
more passive (Experiment 4).
Our research strategy was to look at effects that would carry
over across wide gaps of seeming irrelevance. If resisting the
temptation to eat chocolate can leave a person prone to give up
faster on a difficult, frustrating puzzle, that would suggest that
those two very different acts of self-control draw on the same
limited resource. And if making a choice about whether to make
a speech contrary to one's opinions were to have the same
effect, it would suggest that that very same resource is also the
one used in general for deliberate, responsible decision making.
That resource would presumably be one of the most important
features of the self.
Roy E Baumeister, Ellen Bratslavsky, Mark Muraven, and Dianne M.
Tice, Department of Psychology, Case Western Reserve University.
This research was supported by National Institute of Health Grants
MH-51482 and MH-57039. Experiment 1 was the master's thesis of
Ellen Bratslavsky, directed by Roy E Baumeister. Some of these findings
have been presented orally at several conferences.
Correspondence concerning this article should be addressed to Roy E
Baumeister, Department of Psychology, Case Western Reserve University,
10900 Euclid Avenue, Cleveland, Ohio 44106-7123. Electronic mail may
be sent to rfb2@po.cwru.edu.
Executive Function
The term agency has been used by various writers to refer to
the self's exertion of volition, but this term has misleading
connotations: An agent is quintessentially someone who acts on
behalf of someone else, whereas the phenomenon under discussion
involves the self acting autonomously on its own behalf.
The term executive function has been used in various contexts
to refer to this aspect of self and hence may be preferable (e.g.,
Journal of Personality and Social Psychology, 1998, Vol. 74, No. 5, 1252-1265
Copyright 1998 by the American Psychological Association, Inc. 0022-3514/98/$3.00
1252
EGO DEPLETION 1253
Epstein, 1973; see Baumeister, 1998). Meanwhile, we use the
term ego depletion to refer to a temporary reduction in the
self's capacity or willingness to engage in volitional action
(including controlling the environment, controlling the self,
making choices, and initiating action) caused by prior exercise
of volition.
The psychological theory that volition is one of the self's
crucial functions can be traced back at least to Freud (1923/
1961a, 1933/1961b), who described the ego as the part of the
psyche that must deal with the reality of the external world by
mediating between conflicting inner and outer pressures. In his
scheme, for example, a Victorian gentleman standing on the
street might feel urged by his id to head for the brothel and by
his superego to go to church, but it is ultimately left up to his
ego to start his feet walking in one direction or the other. Freud
also seems to have believed that the ego needed to use some
energy in making such a decision.
Recent research has convincingly illuminated the self's
nearly relentless quest for control (Brehm, 1966; Burger, 1989;
DeCharms, 1968; Deci & Ryan, 1991, 1995; Langer, 1975;
Rothbaum, Weisz, & Snyder, 1982; Taylor, 1983, 1989; White,
1959). It is also known that when the self feels highly responsible
(accountable) for its actions, its cognitive and behavioral
processes change (Cooper & Scher, 1994; Linder, Cooper, &
Jones, 1967; Tetlock, 1983, 1985; Tetlock & Boettger, 1989).
Active responses also have more powerful effects on the self
and its subsequent responses than do passive ones (Allison &
Messick, 1988; Cioffi & Garner, 1996; Fazio, Sherman, & Herr,
1982). The processes by which the self monitors itself in order
to approach standards of desired behavior have also been studied
(Carver & Scheier, 1981; Duval & Wicklund, 1972; Wegner,
1994; Wegner & Pennebaker, 1993).
Despite these efforts, it is hard to dispute that understanding
of the executive function remains far more vague and rudimentary
than other aspects of self-theory. Researchers investigating
cognitive representations of self have made enormous progress
in recent decades (for reviews, see Banaji & Prentice, 1994;
Fiske & Taylor, 1991). Likewise, there has been considerable
progress on interpersonal aspects of selfhood (e.g., Leary, 1995;
Leary & Kowalski, 1990; Schlenker, 1980; Tesser, 1988). In
comparison, understanding of the self's executive function lags
behind at a fairly primitive level.
power be revived for self-regulation theory, and a literature review
by Baumeister, Heatherton, and Tice (1994) concluded
that much evidence about self-regulatory failure fits a model of
strength depletion.
An important early study by Glass, Singer, and Friedman
(1969) found that participants exposed to unpredictable noise
stress subsequently showed decrements in frustration tolerance,
as measured by persistence on unsolvable problems,t Glass et
al. concluded that adapting to unpredictable stress involves a
"psychic cost," which implies an expenditure or depletion of
some valuable resource. They left the nature of this resource to
future research, which has not made much further progress.
Additional evidence for a strength model was provided by
Muraven, Tice, and Baumeister (1998), whose research strategy
influenced the present investigation. Muraven et al. sought to
show that consecutive exertions of self-regulation were characterized
by deteriorating performance, even though the exertions
involved seemingly unrelated spheres. In one study, they showed
that trying not to think about a white bear (a thought-control
task borrowed from Wegner, 1989; Wegner, Schneider, Carter, &
White, 1987) caused people to give up more quickly on a subsequent
anagram task. In another study, an affect-regulation exercise
caused subsequent decrements in endurance at squeezing a
handgrip. These findings suggest that exertions of self-control
do carry a psychic cost and deplete some scarce resource.
To integrate these scattered findings and implications, we suggest
the following. One important part of the self is a limited
resource that is used for all acts of volition, such as controlled
(as opposed to automatic) processing, active (as opposed to
passive) choice, initiating behavior, and overriding responses.
Because much of self-regulation involves resisting temptation
and hence overriding motivated responses, this self-resource
must be able to affect behavior in the same fashion that motivation
does. Motivations can be strong or weak, and stronger impulses
are presumably more difficult to restrain; therefore, the
executive function of the self presumably also operates in a
strong or weak fashion, which implies that it has a dimension
of strength. An exertion of this strength in self-control draws
on this strength and temporarily exhausts it (Muraven et al.,
1998), but it also presumably recovers after a period of rest.
Other acts of volition should have similar effects, and that is
the hypothesis of the present investigation.
Ego Depletion
The notion that volition depends on the self's expenditure of
some limited resource was anticipated by Freud (1923/1961a,
1933/1961b). He thought the ego needed to have some form
of energy to accomplish its tasks and to resist the energetic
promptings of id and superego. Freud was fond of the analogy
of horse and rider, because as he said the rider (analogous to
the ego) is generally in charge of steering but is sometimes
unable to prevent the horse from going where it wants to go.
Freud was rather vague and inconsistent about where the ego's
energy came from, but he recognized the conceptual value of
postulating that the ego operated on an energy model.
Several modern research findings suggest that some form of
energy or strength may be involved in acts of volition. Most of
these have been concerned with self-regulation. Indeed, Mischel
(1996) has recently proposed that the colloquial notion of willExperiment
1
Experiment 1 provided evidence for ego depletion by examining
consecutive acts of self-control. The study was originally
designed to test competing hypotheses about the nature of selfcontrol,
also known as self-regulation. Clearly the control over
self is one of the most important and adaptive applications of
the self's executive function. Research on monitoring processes
and feedback loops has illuminated the cognitive structure that
1These researchers also showed that an illusion of controllability
eliminated this effect. From our perspective, this impliesthat part of the
stress involves the threat or anticipation of continued aversive stimulation,
which the illusion of controllability dispelled. In any case, it is
plausible that the psychic cost was paid in terms of affect regulation,
that is, making oneself submit and accept the aversive, unpredictable
stimulation.
1254 BAUMEISTER, BRATSLAVSKY, MURAVEN, AND TICE
processes relevant information (e.g., Carver & Scheier, 1981;
Wegner, 1994), but the actual process by which an organism
alters its own responses or subjective states is far less well
understood. At least three different models of the nature of selfregulation
can be proposed. Moreover, these three models make
quite different predictions about the effectiveness of self-control
immediately after an exertion of self-control in some unrelated
sphere. Experiment 1 provided a test of these three competing
predictions by requiring participants to engage in two seemingly
unrelated acts of self-control.
One model views self-regulation as essentially a skill. In this
model, people gradually develop the skill to regulate themselves
over long periods of time. On any given occasion, however, skill
remains roughly constant across repeated trials (except for small
and gradual learning effects), so there should be little or no
change in effectiveness of self-control on two successive exertions
within a short time.
Another model portrays self-regulation as essentially a
knowledge structure. In this view, self-control operates like a
master schema that makes use of information about how to alter
one's own responses or states. On the basis of this model, an
initial act of self-regulation should prime the schema, thereby
facilitating subsequent self-control. Another version of this view
would be that the self-regulatory system is normally in a standby
or depowered mode until it is pressed into action by one act of
self-control. Once activated, the system would remain in operation
( "on" ) for a time, making further acts of self-control easier.
A third model states that self-regulation resembles energy. In
this view, acts of self-regulation involve some kind of exertion
that expends energy and therefore depletes the supply available.
Unless the supply is very large, initial acts of self-regulation
should deplete it, thereby impairing subsequent self-control.
Thus, the three models respectively predict no change, an
increase, or a decrease in effectiveness of self-control following
an initial act of self-control. Other models are possible, such as
the possibility that self-regulation involves a collection of domain-specific
but unrelated knowledge structures, so that an
initial act of self-control should prime and therefore facilitate
self-control in the same sphere but produce no change in other,
unrelated spheres. Still, these three models provide sufficiently
conflicting predictions about the sequence of unrelated acts of
self-control to make it worth conducting an initial test.
In the present research, we used impulse control, which to
many people is the classic or paradigmatic form of self-control.
More precisely, we manipulated self-control by instructing some
hungry individuals to eat only radishes while they were faced
with the tempting sight and aroma of chocolate. Thus, they had
to resist the temptation to perform one action while making
themselves perform a similar but much less desirable action.
We then sought to measure self-control in an unrelated sphere,
by persistence at a frustrating puzzle-solving task. A series of
frustrating failures may often make people want to stop doing
the task, and, so, self-control is needed to force oneself to continue
working.
If resisting temptation depends on skill, then this skill would
predict no change in persistence under frustration. If resisting
temptation involves activating a knowledge structure or master
schema, then priming this schema should facilitate self-control,
and people should persist longer on the puzzles. Finally, if resisting
temptation uses some kind of strength or energy, then this
will be depleted afterward, and subsequent persistence should
decrease.
Method
Participants. Data were collected in individual sessions from 67
introductory psychology students (31 male, 36 female) who received
course credit for taking part.
Procedure. Participants signed up for a study on taste perception.
Each participant was contacted to schedule an individual session, and
at that time the experimenter requested the participant to skip one meal
before the experiment and make sure not to have eaten anything for at
least 3 hr.
The laboratory room was carefully set up before participants in the
food conditions arrived. Chocolate chip cookies were baked in the room
in a small oven, and, as a result, the laboratory was filled with the
delicious aroma of fresh chocolate and baking. Two foods were displayed
on the table at which the participant was seated. One display consisted
of a stack of chocolate chip cookies augmented by some chocolate
candies. The other consisted of a bowl of red and white radishes.
The experimenter provided an overview of the procedures, secured
an informed consent, and then elaborated the cover story. She explained
that chocolates and radishes had been selected for the taste perception
study because they were highly distinctivefoods familiar to most people.
She said that there would be a follow-up measure for sensation memory
the next day, and so she asked the participant to agree not to eat any
chocolates or radishes (other than in the experiment) for 24 hr after the
session.
Participants in the chocolate and radish conditions were then asked
to take about 5 min to taste the assigned food while the experimenter
was out of the room. In the radish condition, the experimenter asked
the participant to eat at least two or three radishes, and in the chocolate
condition, the participant was asked to eat at least two or three cookies
or a handful of the small candies. Participants were reminded to eat only
the food that had been assigned to them. The experimenter left the room
and surreptitiously observed the participant through a one-way mirror,
recording the amount of food eaten and verifying that the participant
ate only the assigned food. (To minimize self-awareness, the mirror was
almost completely covered with a curtain.)
After about 5 min, the experimenter returned and asked the participant
to fill out two questionnaires. One was the Brief Mood Introspection
Scale (BMI; Mayer & Gaschke, 1988), and the other was the Restraint
Scale (Herman & Polivy, 1975). Then the experimenter said that it was
necessary to wait at least 15 min to allow the sensory memory of the
food to fade. During that time, she said, the participant would be asked
to provide some preliminary data that would help the researchers learn
whether college students differed from high school students in their
problem-solving ability. The experimenter said that the participant would
therefore be asked to work on a test of problem solving. The problem
solving was presented as if it were unrelated to the eating, but in fact
it constituted the main dependent measure.
There was also a no-food control condition. Participants assigned to
this condition skipped the food part of the experiment and went directly
to the problem-solving part.
The problem-solving task was adapted from a task used by Glass et
al. (1969), adapted from Feather ( 1961 ). The puzzle requires the person
to trace a geometric figure without retracing any lines and without lifting
his or her pencil from the paper. Multiple slips of paper were provided
for each figure, so the person could try over and over. Each participant
was initially given several practice figures to learn how the puzzles
worked and how to solve them, with the experimenter present to answer
any questions. After the practice period, the experimenter gave the participant
the two main test figures with the instructions
You can take as much time and as many trials as you want. You
will not be judged on the number of trials or the time you will take.
EGO DEPLETION 1255
You will be judged on whether or not you finish tracing the figure.
If you wish to stop before you finish [i.e., solve the puzzle], ring
the bell on the table.
Unbeknownstto the participant, both these test figures had beenprepared
so as to be impossible to solve.
The experimenter thenleft the room andtimedhow longthe participant
worked on the task before giving up (signified by ringing the bell).
Following an a priori decision, 30 rain was set as the maximum time,
and the 4 participants who were still working after 30 min were stopped
by the experimenter at that point. For the rest, when the experimenter
heard the bell, she reentered the room and administered a manipulation
check questionnaire. When the participants finished, the experimenter
debriefed, thanked, and dismissed them.
Results
Manipulation check. The experimenter surreptitiously observed
all participants during the eating phase to ascertain that
they ate the stipulated food and avoided the other. All participants
complied with the instructions. In particular, none of the
participants in the radish condition violated the rule against
eating chocolates. Several of them did exhibit clear interest in
the chocolates, to the point of looking longingly at the chocolate
display and in a few cases even picking up the cookies to sniff
at them. But no participant actually bit into the wrong food.
The difficulty of the eating task was assessed on the final
questionnaire. Participants in the radish condition said that they
forced themselves in an effortful fashion to eat the assigned
food more than participants in the chocolate condition, F(1,
44) = 16.10, p < .001. They also rated resisting the nonassigned
food as marginally significantly mdre difficult, F( 1, 44) = 3.41,
p < .07. During the debriefing, many participants in the radish
condition spontaneously mentioned the difficulty of resisting the
temptation to eat the chocolates.
Persistence. The main dependent measure was the amount
of time participants spent on the unsolvable puzzles. A one-way
analysis of variance (ANOVA) indicated significant variation
among the three conditions, F(2, 64) = 26.88, p < .001. The
means are presented in Table 1. Pairwise comparisons among
the groups indicated that participants in the radish condition
quit sooner on the frustrating task than did participants in either
the chocolate condition, t(44) = 6.03, p < .001, or the no-food
(control) condition, t(44) = 6.88, p < .001. The chocolate
condition did not differ from the no-food control condition,
t< 1, ns.
It is conceivable that the time measure was affected by something
other than persistence, such as speed. That is, the interpretation
would be altered if the participants in the radish condition
tried just as many times as those in the chocolate condition and
Table 1
Persistence on Unsolvable Puzzles (Experiment 1)
merely did so much faster. Hence, we also analyzed the number
of attempts that participants made before giving up. A oneway
ANOVA on these tallies again yielded significant variation
among the three conditions, F(2, 64) = 7.61, p = .001. The
pattern of results was essentially the same as with duration of
persistence, as can be seen in Table 1. Pairwise comparisons
again showed that participants in the radish condition gave up
earlier than participants in the other two conditions, which did
not differ from each other.2
Moods. The mood measure contains two subscales, and we
conducted a one-way ANOVA on each, using only the radish
and chocolate conditions (because this measure was not administered
in the no-food control condition). The two conditions
did not differ in valence (i.e., pleasant vs. unpleasant) of mood,
F(1, 44) = 2.62, ns, nor in arousal, F < 1, ns.
Dieting. The analyses on persistence were repeated using
dieting status (from the Restraint Scale) as an independent variable.
Dieting status did not show either a main effect or an
interaction with condition on either the duration of persistence
or the number of attempts.
Fatigue and desire to quit. The final questionnaire provided
some additional evidence beyond the manipulation checks. One
item asked the participant how tired he or she felt after the
tracing task. An ANOVA yielded significant variation among the
conditions, F(2, 64) = 5.74, p < .01. Participants in the radish
condition were more tired (M = 17.96) than those in the chocolate
(M = 11.85 ) or no-food (M = 12.29) conditions (the latter
two did not differ). Participants in the radish condition also
reported that their fatigue level had changed more toward increased
tiredness (M --- 6.28) than participants in either the
chocolate (M = -0.90) or no-food (M = 1.76) conditions,
F(2, 64) = 5.13, p < .01.
Participants in the radish condition reported that they had felt
less strong a desire to stop working on the tracing task than had
participants in the other two conditions, F(2, 64) = 4.71, p <
.01. Yet they also reported forcing themselves to work on the
tracing task more than participants in the other two conditions,
F(2, 64) = 3.20, p < .05. The latter may have been an attempt
to justify their relatively rapid quitting on that task. The former
may indicate that they quit as soon as they felt the urge to do
so, in contrast to the chocolate and no-food participants who
made themselves continue for a while after they first felt like
quitting.
Discussion
These results provide initial support for the hypothesis of
ego depletion. Resisting temptation seems to have produced a
psychic cost, in the sense that afterward participants were more
inclined to give up easily in the face of frustration. It was not
that eating chocolate improved performance. Rather, wanting
chocolate but eating radishes instead, especially under circumCondition
Time (min) Attempts
Radish 8.35 19.40
Chocolate 18.90 34.29
No food control 20.86 32.81
Note. Standard deviations for Column 1, top to bottom, are 4.67, 6.86,
and 7.30. For Column 2, SDs = 8.12, 20.16, and 13.38.
2As this article went to press, we were notified that this experiment
had been independently replicated by Timothy J. Howe, of Cole Junior
High School in East Greenwich, Rhode Island, for his science fair project.
His results conformed almost exactly to ours, with the exception
that mean persistence in the chocolate condition was slightly (but not
significantly) higher than in the control condition. These converging
results strengthen confidence in the present findings.
1256 BAUMEISTER, BRATSLAVSKY, MURAVEN, AND TICE
stances in which it would seemingly be easy and safe to snitch
some chocolates, seems to have consumed some resource and
therefore left people less able to persist at the puzzles.
Earlier, we proposed three rival models of the nature of selfregulation.
These results fit a strength model better than a skill or
schema model. If self-regulation were essentially a knowledge
structure, then an initial act of self-regulation should have
primed the schema, thereby facilitating subsequent self-regulation.
The present results were directly opposite to that prediction.
A skill model would predict no change across consecutive
acts of self-regulation, but we did find significant change. In
contrast, a strength or energy model predicted that some vital
resource would be depleted by an initial act of self-regulation,
leading to subsequent decrements, and this corresponds to what
we found.
It is noteworthy that the depletion manipulation in this study
required both resisting one impulse (to eat chocolate) and making
oneself perform an undesired act (eating radishes). Both
may have contributed to ego depletion. Still, the two are not
independent. Based on a priori assumptions and on comments
made by participants during the debriefing, it seems likely that
people would have found it easier to make themselves eat the
radishes if they were not simultaneously struggling with resisting
the more tempting chocolates.
Combined with other evidence (especially Muraven et al.,
1998), therefore, it seems reasonable to infer that self-regulation
draws on some limited resource akin to strength or energy and
that this resource may be common for many forms of selfregulation.
In Experiment 1, we found that an initial act of
resisting temptation (i.e., an act of impulse control) impaired
subsequent persistence at a spatial puzzle task. Muraven et al.
found that an act of affect regulation (i.e., trying either to stifle
or amplify one's emotional response) lowered subsequent stamina
on a physical task, that an initial act of thought suppression
reduced persistence at unsolvable anagrams, and that thought
suppression impaired subsequent ability to hide one's emotions.
These various carryovers between thought control, emotion control,
impulse control, and task performance indicate that these
four main spheres of self-regulation all share the same resource.
Therefore, the question for Experiment 2 was whether that same
resource would also be involved in other acts of choice and
volition beyond self-regulation.
Experiment 2
Experiment 2 addressed the question of whether the same
resource that was depleted by not eating chocolate (in Experiment
1) would be depleted by an act of choice. For this, we
used one of social psychology's classic manipulations: High
choice versus low choice to engage in counterattitudinal behavior.
Festinger and Carlsmith (1959) showed that people change
their attitudes to make them consistent with behavior when they
have been induced to act in ways contrary to their attitudes.
Linder et al. (1967) showed that this effect occurs only when
people have been led to see their own (counterattitudinal) behavior
as freely chosen, and many studies have replicated these
effects.
Our interest was not in the attitudinal consequences of counterattitudinal
behavior, however. Rather, our hypothesis was that
the act of making the choice to engage in counterattitudinal
behavior would involve the self and deplete its volitional resource.
As an index of this ego depletion, we measured frustration
tolerance using the same task that we used in Experiment
1, namely persistence at unsolvable puzzles. The puzzles, of
course, had nothing to do with our independent variable (next
year's tuition), and so in all direct ways the two behaviors were
irrelevant.
Dissonance research has provided some evidence consistent
with the view that making a choice involves an exertion by the
self. The original article by Linder et al. (1967) reported that
participants in the high-choice (free-decision, low-incentive)
condition spent about half a minute deciding whether to engage
in the counterattitudinal behavior, even though all consented to
do it, whereas low-choice participants did not spend that amount
of time. This is consistent with the view that the self was engaging
in some effortful activity during the choice exercise. More
generally, Cooper and Scher (1994; see also Cooper & Fazio,
1984; Scher & Cooper, 1989) concluded that personal responsibility
for aversive consequences is the core cause of cognitive
dissonance, and their conclusion puts emphasis on the taking
or accepting of personal responsibility for one's actions--thus
an active response by the self.
The design of Experiment 2 thus involved having people
make a counterattitudinal speech (favoring a large tuition increase,
to which most students were opposed) under high- or
low-choice conditions. Because our focus was on the active
choice making by the self, we also included a condition in
which people chose to make a proattitudinal speech opposing
the increase. Choosing to engage in a proattitudinal behavior
should not cause dissonance (see Cooper & Scher, 1994; Cooper
& Fazio, 1984; Festinger, 1957; Linder et al., 1967), but it
should still deplete the self to some degree because it still involves
an act of choice and taking responsibility. We did not
have any basis for predicting whether choosing to engage in
counterattitudinal behavior would deplete the self more than
choosing to engage in proattitudinal behavior, but we expected
that there should still be some depletion.
Me~od
Participants. Participants were 39 undergraduate psychology students
(25 male, 14 female). They participated in individual sessions.
They were randomlyassigned among four experimental treatment conditions:
counterattitudinal choice, counterattitudinal no choice, proattitudinal
choice, and no speech (control). Toensure that the issue was personally
relevant to all participants, we excluded 8 additional potential participants
who were either graduating seniors or who were on full
scholarship, because preliminarytesting revealed that next year's tuition
did not matter to students in these categories.
Procedure. The experimenter greeted each participant and explained
that the purpose of the study was to see how people respond to persuasion.
They were told that they would be making stimuli that would be
played to other people to alter their attitudes. In particular, they would
be making an audiotape recording of a persuasive speech regarding
projected tuition increases for the following academic year. The topic
of tuition raises was selected on the basis of a pilot test: A survey had
found that students rated the tuitionincrease as the most important issue
to them.
The experimenter said that all participants would record speeches that
had been prepared in advance. The importance of the tuition increase
issue was highlighted. The experimenter also said that the university's
EGO DEPLETION 1257
Board of Trustees had agreed to listen to the speeches to see how much
impact the messages would have on their decisions about raising tuition.
The experimenter showed the participant two folders, labeled protuition
raise and anti-tuition raise. Participants in the n0-choice (counterattitudinal)
condition were told that they had been assigned to make
the pro-tuition raise speech. The experimenter said that the researchers
already had enough people making the speech against the tuition raise
and so it would not be possible to give the participant a choice as to
which speech to make. In contrast, participants in the high-choice conditions
were told that the decision of which speech to make was entirely
up to them. The experimenter explained that because there were already
enough participants in one of the groups, it would help the study a great
deal if they chose to read one folder rather than the other. The experimenter
then again stressed that the final decision would remain entirely
up to the participant. All participants agreed to make the speech that
they had been assigned.
Participants in the no-speech control condition did not do this part
of the experiment. The issue of tuition increase was not raised with
them.
At this point, all participants completed the same mood measure used
in Experiment 1. The experimenter then began explaining the task for
the second part of the experiment. She said there was some evidence of
a link between problem-solving abilities and persuasiveness. Accordingly,
the next part of the experiment would contain a measure of problem-solving
ability. For participants in the speech-making conditions,
the experimenter said that the problem-solving task would precede the
recording of the speech.
The problem-solving task was precisely the same one used in Experiment
1, involving tracing geometric figures without retracing lines or
lifting the pen from the paper. As in Experiment 1, the participant's
persistence at the frustrating puzzles was the main dependent measure.
After signaling the experimenter that they wished to stop working on
the task, participants completed a brief questionnaire that included manipulation
checks. They were then completely debriefed, thanked, and
sent home.
Table 2
Persistence on Unsolvable Puzzles (Experiment 2)
Condition Time (min) Attempts
Counterattitudinal speech
High choice 14.30 26.10
No choice 23.11 42.44
Proattitudinal speech
High choice 13.80 24.70
No speech control 25.30 35.50
Note. Standard deviations for Column 1, top to bottom, are 6.91, 7.08,
6.49, and 5.06. For Column 2, SDs = 14.83, 22.26, 7.13, and 9.14.
Similar results were found using the number of attempts
(rather than time) as the dependent measure of persistence. The
ANOVA indicated significant variation among the four conditions,
F(3, 35) = 3.24, p < .05. The same pattern of pairwise
cell differences was found: Both conditions involving high
choice led to a reduction in persistence, as compared with the
no-speech control condition and the no-choice counterattitudinal
speech condition. 3
Mood state. One-way ANOVAs were conducted on each of
the two subscales of the BMI Scale. There was no evidence of
significant variation among the four conditions in reported valence
of mood (i.e., pleasant vs. unpleasant), F(3, 35) < 1,
ns. There was also no evidence of variation in arousal, F(3,
35) < 1, ns. These results suggest that the differences in persistence
were not due to differential moods engendered by the
manipulations.
Discussion
Results
Manipulation check. The final questionnaire asked participants
(except in the control condition) how much they felt that
it was up to them which speech they chose to make. A one-way
ANOVA confirmed that there was significant variation among
the conditions, F(2, 31) = 15.46, p < .001. Participants in the
no-choice condition indicated that it was not up to them which
speech to make (M = 27.10), whereas participants in the counterattitudinal-choice
(M = 10.21) and proattitudinal-choice
conditions (M = 6.60) both indicated high degrees of choice.
Another item asked how much the participant considered reading
an alternative speech to the one suggested by the experimenter,
and on this too there was significant variation among
the three conditions, F(2, 31) = 11.53, p < .001, indicating
that high-choice participants considered the alternative much
more than participants in the no-choice condition.
Persistence. The main dependent measure was the duration
of persistence on the unsolvable puzzles. The results are presented
in Table 2. A one-way ANOVA on persistence times
indicated that there was significant variation among conditions,
F(3, 35) = 8.42, p < .001. Pairwise comparisons confirmed
that the counterattitudinal-choice and the proattitudinal-choice
conditions each differed significantly from both the control and
the counterattitudinal-no-choice conditions. Perhaps surprisingly,
the two choice conditions did not differ significantly from
each other.
The results supported the ego depletion hypothesis and suggest
that acts of choice draw on the same limited resource used
for self-control. Participants who agreed to make a counterattitudinal
speech under high choice showed a subsequent drop in
their persistence on a difficult, frustrating task, as compared
with participants who expected to make the same speech under
low choice (and as compared with no-speech control participants).
Thus, taking responsibility for a counterattitudinal behavior
seems to have consumed a resource of the self, leaving
the self with less of that resource available to prolong persistence
at the unsolvable puzzles.
Of particular further interest was the high-choice proattitudinal
behavior condition. These people should not have experienced
any dissonance, yet they showed significant reductions
in persistence on unsolvable problems. Dissonance is marked
3The differences between the control condition and the two highchoice
conditions failed to reach significance if we used the error term
from the ANOVA as the pooled variance estimate. The proattitudinalchoice
condition did differ from the control condition in a standard t
test using only the variance in those two cells, t(18) = 2.94, p < .01.
The counterattitudinal-choice condition differed marginally from the
no-speech control using this latter method, t(18) = 1.71, p = .105. The
high variance in the counterattitudinal-no-choice condition entailed that
it also differed only marginally from the counterattitudinal-choice condition
if the actual variance in those cells was used rather than the error
term, t(17) = 1.90, p = .07.
1258 BAUMEISTER, BRATSLAVSKY, MURAVEN, AND TICE
by an aversive arousal state (Cooper, Zanna, & Taves, 1978;
Zanna & Cooper, 1974; Zanna, Higgins, & Taves, 1976), but
apparently this arousal or negative affect is not what is responsible
for ego depletion, because we found almost identical evidence
of ego depletion among people who chose to make the
nondissonant, proattitudinal speech.
Thus, it is not the counterattitudinal behavior that depletes
the self. Indeed, people who expected to perform the counterattitudinal
behavior under low choice persisted just as long as nospeech
control participants. Making a speech contrary to one's
beliefs does not necessarily deplete the self in any way that our
measure detected. Meanwhile, making a speech that supports
one's beliefs did deplete the self, provided that the person made
the deliberate, free decision to do so.
The implication is that it is the exercise of choice, regardless
of the behavior, that depletes the self. Whatever motivational,
affective, or volitional resource is needed to force oneself to
keep trying in the face of discouraging failure is apparently the
same resource that is used to make responsible decisions about
one's own behavior, and apparently this resource is fairly
limited.
Experiment 3
Experiments 1 and 2 suggested that self-regulation is weakened
by prior exercise of volition, either in the form of resisting
temptation (Experiment 1) or making a responsible choice (Experiment
2). In both studies, the dependent variable involved
persistence on unsolvable problems. It is reasonable to treat
such persistence as a challenge for self-regulation, because undoubtedly
people would feel inclined to give up when their
efforts are met with frustration and discouraging failure, and
overcoming that impulse (in order to persist) would require an
act of self-control.
An alternative view, however, might suggest that it is adaptive
to give up early on unsolvable problems. Persistence is, after all,
only adaptive and productive when it leads to eventual success.
Squandering time and effort on a lost cause is thus wasteful,
and optimal self-management would involve avoiding such
waste (e.g., McFarlin, 1985). It is true that such an argument
would require one to assume that our participants actually recognized
the task as unsolvable, and there was no sign that they
did. (In fact, most participants expressed surprise during the
debriefing when they were told that the puzzles were in fact
unsolvable.) Yet for us to contend that ego depletion has a
negative effect, it seemed necessary to show some decrement
in task performance. Unsolvable puzzles cannot show such a
decrement, because no amount of persistence leads to success.
Study 3 therefore was designed to show that ego depletion can
impair performance on solvable tasks.
Because broad conclusions about ego depletion are difficult
to draw from any single procedure, it seemed desirable to use
very different procedures for Study 3. Accordingly, the manipulation
of ego depletion involved affect regulation (i.e., controlling
one's emotions). Affect regulation is one important sphere
of self-regulation (e.g., Baumeister et al., 1994). In this study,
some participants were asked to watch an emotionally evocative
videotape and stifle any emotional reaction they might have. To
ensure that the effects were due to self-regulation rather than
the particular emotional response, we used both positive (humorous)
and negative (sad and distressing) stimuli.
For the measure of task performance, we selected anagram
solving. This is a widely used performance measure that has
elements of both skill and effort. More to the point, we suspected
that success at anagrams would require some degree of selfregulation.
One must keep breaking and altering the tentative
combinations of letters one has formed and must make oneself
keep trying despite multiple initial failures. In the latter respect,
anagram solving resembles the dependent measure used in the
first two studies, except that persistence can actually help lead
to success. The prediction was that participants who had tried
to control their emotional responses to the videotape would
suffer from ego depletion and, as a result, would perform more
poorly at anagrams.
Me~od
Participants. Participants were 30 (11 male and 19 female) undergraduates
who took part in connection with introductory psychology
requirements. They participated in individual sessions and were randomly
assigned among the conditions.
Procedure. The experimenter explained that the purpose of the study
was to see which personality traits would make people more responsive
to experiencing emotions. They were told that the first part of the procedure
would involve watching a movie.
In the suppress-emotion condition, participants were instructed to try
not to show and not to feel any emotions during the movie. The experimenter
said that the participant would be videotaped while watching the
film, and so it was essential to try to conceal and suppress any emotional
reaction. Meanwhile, participants in the no-regulation condition were
instructed to let their emotions flow while watching the movie, without
any attempt to hide or deny these feelings. They were also told that
their reactions would be videotaped.
Following these instructions, each participant saw a 10-min videotape.
Half of the participants in each condition saw a humorous video featuring
the comedian Robin Williams. The others saw an excerpt from the
film TermsofEndearment, portraying a young mother dying from cancer.
At the end of the video clip, participants completed the BMI Scale.
Then the experimenter extended the cover story to say that they would
have to wait at least 10 min after the film to allow their sensory memory
of the movie to fade. During that time, they were asked to help the
experimenter collect some preliminary data for future research by completing
an anagram task. Participants received 13 sets of letters that they
were to unscramble to make English words during a 6-min period. The
participant was left alone to do this task. After 6 min, the experimenter
returned and administered a postexperimental questionnaire. After the
participant completed that, he or she was debriefed and thanked.
Results
Manipulation check. The final questionnaire asked participants
to rate how effortful it had been to comply with the
instructions for watching the video clip. Participants in the suppress-emotion
condition reported that they found it much more
effortful (M = 13.88) than participants in the no-regulation
condition (M = 5.64), t(28) = 2.88, p < .01. Similar effects
were found on an item asking people how difficult it was to
follow the instructions while following the video, t(28) = 4.95,
p < .001, and on an item asking how much they had to concentrate
in complying with the instructions, t(28) = 5.42, p <
.001. These findings confirm that it required a greater exertion
to suppress one's emotional response than to let it happen.
EGO DEPLETION 1259
In addition, the films were perceived quite differently. On the
item asking participants to rate the movie on a scale ranging
from 1 (sad) to 25 (funny), participants rated the comedy video
as much funnier (M = 21.94) than the sad video clip (M =
4.54), t(29) = 4.62, p < .001. There were no differences as
a function of ego depletion condition in how the movie was
perceived.
Anagram performance. The main dependent variable was
performance on the anagram task. Table 3 shows the results.
Participants in the suppress-emotion condition performed significantlyworse
than participants in the no-regulationcondition
in terms of number of anagrams correctly solved, t(28) = 2.12,
p < .05. There was no effect for type of movie.
Mood. There was no difference in either mood valence or
arousal between participants who tried to suppress their emotional
reactions and those who let their emotions go. Hence any
differences in performance between these conditions should not
be attributed to differential mood or arousal responses.
Discussion
The results confirm the view that ego depletion can be detrimental
to subsequent performance. The alternative view, that
Experiments 1 and 2 showed improved self-regulation because
it is adaptive to give up early on unsolvable tasks, cannot seemingly
account for the results of Experiment 3. In this study, an
act of self-regulation--stiflingone's emotional response to a
funny or sad video clip--was followed by poorer performance
at solving anagrams. Hence, it seems appropriate to suggest that
some valuable resource of the self was actually depleted by the
initial act of volition, as opposed to suggesting merely that initial
acts of volition alter subsequent decision making.
Experiment 4
The first three experiments provided support for the hypothesis
of ego depletion. Experiment 4 was designed to provide
converging evidence using quite different procedures. Also, Experiment
4 was designed to complement Experiment 2 by reversing
the direction of influence: Experiment 2 showed that
an initial act of responsible decision making could undermine
subsequent self-regulation, and Experiment 4 was designed to
show that an initial act of self-regulation could undermine subsequent
decision making.
Experiment 4 used procedures that contrasted active versus
passive responding. In many situations, people face a choice
between one course of action that requires an active response
and another course that will occur automatically if the person
does nothing (also called a default option). In an important
study, Brockner, Shaw, and Rubin (1979) measured persistence
in a futile endeavor under two contrasting situations. In one,
Table 3
Success at Solvable Puzzles (Experiment 3)
Condition Solved SD
Suppress 4.94 2.59
No regulation 7.29 3.52
the person had to make a positive move to continue, but the
procedure would stop automatically if he or she did nothing
(i.e., continuingwas active and quitting was passive). The other
situation was the reverse, in which a positive move was required
to terminate whereas continuingwas automatic unless the person
signaled to quit. Brockner et al. found greater persistence when
persistence was passive than when it was active.
In our view, the findingsof Brockner et al. (1979) may reflect
a broader pattern that can be called a passive-option effect. The
passive-option effect can be defined by saying that in any choice
situation, the likelihood of any option being chosen is increased
if choosing involves a passive rather than an active response.
Sales organizations such as music, book, and film clubs, for
example, find that their sales are higher if they can make the
customer's purchasing response passive rather than active, and
so they prefer to operate on the basis that each month's selection
will automatically be mailed to the customer and billed unless
the customer actively refuses it.
For present purposes, the passive-optioneffect is an important
possible consequence of the limited resources that the self has
for volitionalresponse. Our assumption is that active responding
requires the self to expend some of its resources, whereas passive
responses do not. The notion that the self is more involved and
more implicated by active responding than by passive responding
helps explain evidence that active responses leave
more lasting behavioral consequences. For example, Cioffi and
Garner (1996) showed that people were more likely to follow
through when they had actively volunteered than passively volunteered
for the same act.
The passive-option effect thus provides a valuable forum for
examining ego depletion. Active responses differ from passive
ones in that they require the expenditure of limited resources.
If the self's resources have already been exhausted (i.e., under
ego depletion), the self should therefore be all the more inclined
to favor the passive option.
To forestall confusion, we hasten to point out that the term
choice can be used in two different ways, and so a passive
option may or may not be understood as involving a choice,
depending on which meaning is used. Passive choice is a choice
in the sense that the situation presents the person with multiple
options and the outcome is contingent on the person's behavior
(or nonbehavior). It is, however, not a choice in the volitional
sense, because the person may not perform an intrapsychic act
of volition. FOr example, a married couple who sleeps together
on a given night may be said to have made a choice that night
insofar as they could, in principle, have opted to sleep alone or
with other sleeping partners. Most likely, though, they did not
go through an active-choice process that evening, but rather they
simply did what they always did. The essence of passive options,
in our understanding, is that the person does not engage in an
inner process of choosing or deciding, even though alternative
options are available. Passive choices therefore should not deplete
the self's resources.
In Experiment 4, we showed participants a very boring movie
and gave them a temptation to stop watching it. For some participants
quitting was passive, whereas for others quitting required
an active response; The dependent variable was how long people
persisted at the movie. According to the passive-option effect,
they should persist longer when persisting was passive than when
1260 BAUMEISTER, BRATSLAVSKY, MURAVEN, AND TICE
persisting required active responses. We predicted that ego
depletion would intensify this pattern.
Prior ego depletion was manipulated by altering the instructions
for a task in a way that varied how much the person had
to regulate his or her responses. The basic task involved crossing
out all instances of the letter e in a text. People can learn to do
this easily and quickly; and they become accustomed to scanning
for every e and then crossing it out. To raise the self-regulatory
difficulty, we told people not to cross out the letter e if any of
several other criteria were met, such as if there was another
vowel adjacent to the e or one letter removed. These people
would presumably then scan for each e but would have to override
the response of crossing it out whenever any of those criteria
were met. Their responses thus had to be regulated according
to multiple rules, unlike the others who could simply respond
every time they found an e. Our assumption was that consulting
the complex decision rules and overriding the simple response
would deplete the ego, unlike the simpler version of the task.
Me~od
Participants. Eighty-four undergraduate students (47 maies, 37 femaies)
participated for partial fulfillment of a course requirement. Each
individual testing session lasted about 30 min.
Procedure. The experimenter told participants that the experiment
was designed to look at "whether personality influences how people
perceive movies." After signing an informed consent form, participants
completed several personality questionnaires to help maintain the cover
story. (Except for an item measuring tiredness, the questionnaires are
not relevant to the current study and will not be discussed further.)
Participants then completed the regulatory-depletion task. Each was
given a typewritten sheet of paper with meaningless text on it (a page
from an advanced statistics book with a highly technical style) and told
to cross off all instances of the letter e. For the participants assigned to
the ego-depletion condition, the task was made quite difficult, requiring
them to consult multiple rules and monitor their decisions carefully.
They were told that they should only cross off an e if it was not adjacent
to another vowel or one extra letter away from another vowel (thus,
one would not cross off the e in vowel). Also, the photocopy of the
stimulus page had been lightened, making it relatively difficult to read
and thus further requiring close attention. In contrast, participants in the
no-depletion condition were given an easily legible photocopy with good
contrast and resolution, and they were told to cross off every single e
with no further rules or stipulations.
The experimenter then told participants that they were going to watch
two movies and that after each movie they would answer a few simple
questions about it. He explained that the videos were rather long and
the participant did not have time to watch the complete movie. It would
be up to the participant when to stop. The participant was however
cautioned to "watch the video long enough so that you can understand
what happened and answer a few questions about the video."
The experimenter next gave the participant a small box with a button
attached. Participants were told to ring the buzzer when they were done
watching the movie, at which point the experimenter would reenter the
room and give them a few questions to answer. Half of the participants
were told to press the button down when they wanted to stop (active
quit condition). The others were told to hold down the button as long
as they wanted to watch more of the movie; releasing the button would
cause the movie to stop (passive quit condition). The buzzer was wired
to signal the experimenter when the button was pressed (active quit
condition) or released (passive quit condition). In other words, half of
the participants stopped the movie by pressing down on a button,
whereas the other half of the participants stopped the movie by taking
their hand off of a button.
Participants were then shown a film that had been deliberately made
to be dull and boring. The entire film consisted of an unchanging scene
of a blank white wail with a table and a computer junction box in the
foreground. The movie is just a picture of a wall and nothing ever
happens, although participants were unaware of this fact and were motivated
to keep watching to make sure that nothing did actually occur.
Participants were told that after they stopped watching this video, they
would see another video of highlights from a popular, humorous television
program (SaturdayNightLive). Participants therefore believed that
after they finished watching the aversive, boring picture of a wall they
would get to watch a pleasant, amusing video. This was done to give
participants an added incentive to stop watching the boring video and
also to remove the possibility that stopping the movie would immediately
allow them to leave the experiment; although, to be sure, terminating
the first movie would in fact bring them closer to their presumed goal
of completing the experiment and being able to leave.4
The experimenter left the room, surreptitiously timing how long participants
watched the video. When participants rang the buzzer (either
by pressing or releasing the button, depending on the condition), the
experimenter noted the time and reentered the room. At this point, participants
completed a brief questionnaire about their thoughts while
watching the movie and their level of tiredness. Participants were then
completely debriefed, thanked, and sent home.
Results
Manipulation check. On a 25-point scale, participants assigned
to the difficult-rules condition reported having to concentrate
on the task of crossing off the es more than participants
assigned to the easy-rules condition, t(63) = 2.30, p < .025.
Participants in the ego-depletion condition needed to concentrate
more than participants in the no-depletion condition, which
should have resulted in participants in the ego-depletion condition
using more ego strength than participants in the no-depletion
condition.
Further evidence was supplied by having participants rate
their level of tiredness at the beginning of the experiment and
at the end of the experiment. Participants in the ego-depletion
condition became more tired as the experiment progressed compared
with participants in the no-depletion condition, t(83) =
2.79, p < .01. Changes in level of tiredness can serve as a
rough index of changes in effort exerted and therefore regulatory
capacity (see Johnson, Saccuzzo, & Larson, 1995), and these
results suggest that participants in the ego-depletion condition
indeed used more regulatory strength than participants in the
no-depletion condition.
Movie watching. The main dependent measure was how
long participants watched the boring movie. These results are
presented in Table 4. The total time participants spent watching
the boring movie was analyzed in a 2 (rules) x 2 (button
position) ANOVA. Consistent with the hypothesis, the two-way
interaction between depletion task rules (depletion vs. no depletion)
and what participants did to quit watching the movie (active
quit vs. passive quit) was significant, F(1, 80) = 5.64, p
< .025. A planned comparison confirmed that participants under
ego depletion watched more of the movie when quitting required
an active response than when quitting involved a passive re-
4Of course, participants were informed that they were free to leave
at any time. Still, most participants prefered to complete the procedure
and leave the experiment having accomplished something, as opposed
to leaving in the middle of the procedure.
EGO DEPLETION 1261
sponse, F( 1, 80) = 7.21, p < .01. The corresponding contrast
in the no-depletion condition found no difference in movie duration
as a function of which response was active versus passive,
F( 1, 80) = 0.46, ns. Thus, participants who were depleted were
more likely to take the passive route compared with participants
who were not as depleted.
Additionally,there was a strong trend among participants who
had to make an active response in order to quit: They watched
the movie longer when they were in the ego-depletion condition
than in the no-depletion condition, F(I, 80) = 3.35, p < .07.
In other words, when participants had to initiate an action to
quit, they tended to watch the movie longer when they were
depleted than when they were not depleted. Participants who
had to release the button to quit tended to stop watching the
movie sooner when they were depleted than when they were
not depleted, although this was not statistically significant, F( 1,
80) = 2.33, p < ,15. Participants who had to do less work to
quit tended to quit sooner when they were depleted than when
they were not depleted.
Discussion
The results of Experiment 4 provide further support for the
hypothesis of ego depletion, insofar as ego depletion increased
subsequent passivity. We noted that previous studies have found
a passive-option effect, according to which a given option is
chosen more when it requires a passive response than when it
requires an active response. In the present study, ego depletion
mediated the passive-option effect.
Experiment 4 manipulated ego depletion by having people
complete a complex task that required careful monitoring of
multiple rules and frequent altering of one's responses--more
specifically, they were instructed to cross out every instance of
the letter e in a text except when various other conditions were
met, in which case they had to override the simple response of
crossing out the e. These people subsequently showed greater
passivity in terms of how long they watched a boring movie.
They watched it longer when continuing was passive (and stopping
required an active response) than when continuing required
active responses (and stopping would be passive). Without ego
depletion, we found no evidence of the passive-option effect:
People watched the movie for about the same length of time
regardless of whether stopping or continuing required the active
response.
Thus, Experiment 4 found the passive-option effect only under
ego depletion. That is, only when people had completed an
initial task requiring concentration and careful monitoring of
Table 4
Boredom Tolerance (Experiment 4)
Condition No depletion Depletion
Active quit 88 125
Passive quit 102 71
Difference - 14 54
Note. Numbers are mean durations, in seconds, that participants
watched the boring movie. Bottom row (difference) refers to size of
passive-option effect (the passive quit mean subtracted from the active
quit mean).
one's own responses in relation to rules did people favor the
passive option (regardless of which option was passive). These
findings suggest that people are less inclined to make active
responses following ego depletion. Instead, depleted people are
more prone to continue doing what is easiest, as if carried along
by inertia.
Earlier, we suggested that the results of Experiment 2 indicated
that choice depleted the ego. It might seem contradictory
to suggest that passive choice does not draw on the same resource,
but in fact we think the results of the two studies are
quite parallel. The procedures of Experiment 2 involved active
choice, insofar as the person thought about and consented to a
particular behavior. The no-choice condition corresponded to
passive choice in an important sense, because people did implicitly
have the option of refusing to make the assigned counterattitudinal
speech, but they were not prompted by the experimenter
to go through an inner debate and decision process. The active
choices in Experiment 4 required the self to abandon the path
of least resistance and override any inertia that was based on
how the situation was set up, and so it required the self to
do something. Thus, the high- and low-choice conditions of
Experiment 2 correspond to the active and passive options of
Experiment 4. Only active choice draws on the self's volitional
resource.
General Discussion
The present investigation began with the idea that the self
expends some limited resource, akin to energy or strength, when
it engages in acts of volition. To explore this possibility, we
tested the hypothesis that acts of choice and self-control would
cause ego depletion: Specifically,after one initial act of volition,
there would be less of this resource available for subsequent
ones. The four experiments reported in this article provided
support for this view.
Experiment 1 examined self-regulation in two seemingly unrelated
spheres. In the key condition, people resisted the impulse
to eat tempting chocolates and made themselves eat radishes
instead. These people subsequently gave up much faster on a
difficult, frustrating puzzle task than did people who had been
able to indulge the same impulse to eat chocolate. (They also
gave up earlier than people who had not been tempted.) It takes
self-control to resist temptation, and it takes self-control to make
oneself keep trying at a frustrating task. Apparently both forms
of self-control draw on the same limited resource, because doing
one interferes with subsequent efforts at the other.
Experiment 2 examined whether an act of personal, responsible
choice would have the same effect. It did. People who freely,
deliberately consented to make a counterattitudinal speech gave
up quickly on the same frustrating task used in Experiment 1.
Perhaps surprisingly, people who freely and deliberately consented
to make a proattitudinal speech likewise gave up quickly,
which is consistent with the pattern of ego depletion. In contrast,
people who expected to make the counterattitudinal speech under
low-choice conditions showed no drop in persistence, as
compared with no-speech controls.
Thus, it was the act of responsible choice, and not the particular
behavior chosen, that depleted the self and reduced subsequent
persistence. Regardless of whether the speech was consistent
with their beliefs (to hold tuition down) or contrary to
1262 BAUMEISTER, BRATSLAVSKY,MURAVEN, AND TICE
them (to raise tuition), what mattered was whether they made
a deliberate act of choice to perform the behavior. Making either
choice used up some resource and left them subsequently with
less of whatever they needed to persist at a difficult, frustrating
task. The effects of making a responsible choice were quite
similar to the effects of resisting temptation in Experiment 1.
Experiment 3 was designed to address the alternative explanation
that ego depletion actually improved subsequent self-regulation,
insofar as giving up early on unsolvable problems could
be considered as an adaptive response. In Experiment 3, the
dependent variable was task performance on solvable puzzles.
Ego depletion resulting from an exercise in affect regulation
impaired performance on that task.
We had shown (in Experiment 2) that ego-depletion effects
carried over from responsible decision making to have an impact
on self-regulation. Experiment 4 was designed to show the effect
in the opposite direction, namely that prior exertion of selfregulation
would have an impact on decision making. To do
this, we measured the degree of predominance of the passive
option. People were presented with a choice situation in which
they could respond either actively or passively. We varied the
response format so that the meaning of the passive versus active
response was exchanged in a counterbalanced fashion. Prior ego
depletion (created by having people do a task that required
monitoring their own behavior and multiple, overriding rules)
increased people's tendency to use the passive response.
The assumption underlying Experiment 4 was that active responding
draws on the same resource that the self uses to make
responsible decisions and exert self-control. When that resource
is depleted, apparently, people have less of it available to make
active responses. Therefore, they become more passive.
Taken together, these four studies point toward a broad pattern
of ego depletion. In each of them, an initial act of volition was
followed by a decrement in some other sphere of volition. We
found that an initial act of self-control impaired subsequent selfcontrol
(Study 1), that making a responsible decision impaired
subsequent self-control (Study 2), that self-control lowered performance
on a task that required self-control (Study 3), and
that an initial act of self-control led to increased passivity
(Study 4).
The procedures used in these four studies were deliberately
made to be quite different. We have no way of directly measuring
the internal resource that the self uses for making decisions or
regulating itself. Hence, it seemed important to demonstrate ego
depletion in circumstances as diverse as possible, in order to
rule out the possibilitythat results could be artifacts of a particular
method or a particular sphere of volition. Our view is that
the convergence of findings across the four studies is more
persuasive evidence than any of the individual findings.
Alternative Explanations
It must be acknowledged that the present studies provided no
direct measures of the limited resource and hence no direct
evidence that some inner quantity is diminished by acts of volition.
The view that the active self involves some limited resource
is thus an inference based on behavioral observations. It is
therefore especially necessary to consider possible alternative
interpretations of the effects we have shown.
One alternative view is that some form of negative affect
caused participants in this research to give up early on the
frustrating task. The task was, after all, designed to be frustrating
or discouraging, insofar as it was unsolvable. It seems plausible
that depression or other negative emotions might cause people
to stop working at a task.
Although negative affect can undoubtedly affect persistence,
the present pattern of results does not seem susceptible to an
explanation on the basis of negative affect, for several reasons.
We measured negative affect repeatedly and did not find it to
differ significantly among the conditions in the various experiments.
Moreover, in Experiment 3, we found identical effects
regardless of whether the person was trying to stifle a positive
or a negative emotion. Our work converges with other evidence
that mood effects cannot explain aftereffects of stress (Cohen,
1980).
A second alternative explanation would be that the results
were due to cognitive dissonance, especially insofar as several
of the procedures required counterattitudinal behavior such as
eating radishes instead of chocolate or refusing to laugh at a
funny movie. Indeed, Experiment 2 included a condition that
used a dissonance procedure, namely having people consent
(under high choice) to record a speech in favor of a big tuition
increase, contrary to the private beliefs of nearly all participants.
Still, dissonance does not seem to provide a full explanation of
the present effects. There is no apparent reason that dissonance
should reduce persistence on an unrelated, subsequent task.
Moreover, Experiment 2 found nearly identical effects of choosing
a proattitudinal behavior as for choosing a counterattitudinal
behavior, whereas dissonance should only arise in the latter
condition.
A variation on the first two alternate explanations is that
arousal might have mediated the results. For example, cognitive
dissonance has been shown to be arousing (Zanna & Cooper,
1974), and possibly some participants simply felt too aroused
to sit there and keep struggling with the unsolvable problems.
Given the variations and nonlinearities as to how arousal affects
task performance, the decrement in anagram performance in
Experiment 3 might also be attributed to arousal. Our data do,
however, contradict the arousal explanation in two ways. First,
self-report measures of arousal repeatedly failed to show any
effects. Second, high arousal should presumably produce more
activity rather than passivity, but the effects of ego depletion in
Experiment 4 indicated an increase in passivity. If participants
were more aroused, they should not have also become more
passive as a result.
As already noted, the first two experiments were susceptible
to a third alternative explanation that quitting the unsolvable
problems was actually an adaptive, rational act of good selfregulation
instead of a sign of self-regulation failure. This interpretation
assumes that participants recognized that the problems
were unsolvable and so chose rationally not to waste any more
time on them. This conclusion was contradicted by the evidence
from the debriefing sessions, in which participants consistently
expressed surprise when they learned that the problems had
been unsolvable. More important, Experiment 3 countered that
alternative explanation by showing that ego depletion produced
decrements in performance of solvable problems.
Another explanation, based on equity considerations, would
suggest that experimental participants arrive with an implicit
sense of the degree of obligation they owe to the researchers
EGO DEPLETION 1263
and are unwillingto do more. In this view, for example, a person
might feel that she has done enough by making herself eat
radishes instead of chocolates and therefore feels that she does
not owe the experimenter maximal exertion on subsequenttasks.
Although there is no evidence for such a view, it could reasonably
cover Experiments 1 and 3. It has more difficulty with
Experiment 4, because someone who felt he had already done
enough during the highly difficult version of the initial task
would presumably be less willing to sit longer during a boring
movie, which is the opposite of what happened in the activequit
condition. Experiment 2 also is difficult to reconcile with
this alternative explanation, because the participants did not
actually complete any initial task. (They merely agreed to one.)
Moreover, in that study, the effects of agreeing to make a proattitudinal
speech were the same as the effects of agreeing to make
a counterattitudinalspeech, whereas an equity calculationwould
almost surely assume that agreeing to make the counterattitudinal
speech would be a much greater sacrifice.
Implications
The present results could potentially have implications for
self-theory. The pattern of ego depletion suggests that some
internal resource is used by the self to make decisions, respond
actively, and exert self-control. It appears, moreover, that the
same resource is used for all of these, as indicated by the carryover
patterns we found (i.e., exertion in one sphere leads to
decrements in others). Given the pervasive importance of
choice, responsibility, and self-control, this resource might well
be an important aspect of the self. Most recent research on
the self has featured cognitive representations and interpersonal
roles, and the present research does not in any way question
the value of that work, but it does suggest augmentingthe cognitive
and interpersonal aspects of self with an appreciation of
this volitional resource. The operation Ofthe volitional, agentic,
controlling aspect of the self may require an energy model.
Moreover, this resource appears to be quite surprisingly limited.
In Study 1, for example, a mere 5 rain of resisting temptation
in the form of chocolate caused a reduction by half in how
long people made themselves keep trying at unsolvable puzzles.
It seems surprising to suggest that a few minutes of a laboratory
task, especially one that was not described as excessively noxious
or strenuous, would seriously deplete some important aspect
of the self. Thus, these studies suggest that whatever is
involved in choice and self-control is both an important and
very limited resource. The activities of the self should perhaps
be understood in general as having to make the most of a scarce
and precious resource.
The limited nature of this resource might conceivably help
explain several surprising phenomena that have been studied in
recent years. A classic article by Burger (1989) documented a
broad range of exceptions to the familiar, intuitively appealing
notion that people generally seek and desire control. Under many
circumstances, Burger found, people relinquishor avoid control,
and moreover, even under ordinary circumstances, there is often
a substantial minority of people who do not want control. The
ego-depletion findings of the present investigation suggest that
exerting control uses a scarce and precious resource, and the
self may learn early on to conserve that resource. Avoiding
control under some circumstances may be a strategy for
conservation.
Bargh (1997) has recently shown that the scope of automatic
responses is far wider than many theories have assumed and,
indeed, that even when people seem to be consciously making
controlled responses, they may in fact be responding automatically
to subtle cues (see also Bargh, 1982, 1994). Assuming
that the self is the controller of controlled processes, it is not
surprising that controlled processes should be confined to a
relatively small part of everyday functioning, because they are
costly. Responding in a controlled (as opposed to automatic)
fashion would cause ego depletion and leave the self potentially
unable to respond to a subsequent emergency or to regulate
itself. Hence, staying in the automatic realm would help conserve
this resource.
It is also conceivable that ego depletion is central to various
patterns of psychological difficulties that people experience, especially
ones that require unusual exertions of affect regulation,
choice, or other volition. Burnout, learned helplessness, and
similar patterns of pathological passivity might have some element
of ego depletion. Coping with trauma may be difficult
precisely because the self's volitional resources were depleted
by the trauma but are needed for recovery. Indeed, it is well
established that social support helps people recover from
trauma, and it could be that the value of social support lies
partly in the way other people take over the victim's volitional
tasks (ranging from affect regulation to making dinner), thus
conserving the victim's resources or allowing them time to replenish.
On the darker side, it may be that highly controlled
people who seem to snap and abruptly perpetrate acts of violence
or outrage may be suffering from some abrupt depletion
that has undermined the control they have maintained, possibly
for years, over these destructive impulses. These possible implications
lie far beyond the present data, however.
We acknowledge that we do not have a clear understandingof
the nature of this resource. We can say this much: The resource
functions to connect abstract principles, standards, and intentions
to overt behavior. It has some link to physical tiredness but
is not the same as it. The resource seems to have a quantitative
continuum,like a strength. We find it implausiblethat ego depletion
would have no physiological aspect or correlates at all, but
we are reluctant to speculate about what physiological changes
would be involved. The ease with which we have been able
to produce ego depletion using small laboratory manipulations
suggests that the extent of the resource is quite limited, which
implies that it would be seriously inadequate for directing all
of a person's behavior, so conscious, free choice must remain
at best restricted to a very small proportion of human behavior.
(By the same token, most behavior would have to be automatic
instead of controlled, assuming that controlled processes depend
on this limited resource.) Still, as we noted at the outset, even
a small amount of this resource would be extremely adaptive
in enabling human behavior to become flexible, varied, and
able to transcend the pattern of simply responding to immediate
stimuli.
Concluding Remarks
Our results suggest that a broad assortment of actions make
use of the same resource. Acts of self-control, responsible deci-
1264 BAUMEISTER, BRATSLAVSKY, MURAVEN, AND TICE
sion making, and active choice seem to interfere with other such
acts that follow soon after. The implication is that some vital
resource of the self becomes depleted by such acts of volition. To
be sure, we assume that this resource is commonly replenished,
although the factors that might hasten or delay the replenishment
remain unknown, along with the precise nature of this resource.
If further work can answer such questions, it promises to shed
considerable light on human agency and the mechanisms of
control over self and world.
For now, however, two final implications of the present evidence
about ego depletion patterns deserve reiterating. On the
negative side, these results point to a potentially serious constraint
on the human capacity for control (including self-control)
and deliberate decision making. On the positive side, they
point toward a valuable and powerful feature of human
selfhood.
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Received November 11, 1996
Revision received June 10, 1997
Accepted June 16, 1997 •