Ego Depletion

 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-regulation made 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 inhib-

iting 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 situa-

tional 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 con-

trolling 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 dif-

ficult 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 discus-

sion 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 responsi-

ble (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 rudimen-

tary 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 self hood (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 re-

view 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 charac-

terized 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 subse-

quent anagram task. In another study, an affect-regulation exer-

cise 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 sug-

gest 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 motiva-

tion does. Motivations can be strong or weak, and stronger im-

pulses 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 will-

Experiment 1

Experiment 1 provided evidence for ego depletion by examin-

ing consecutive acts of self-control. The study was originally

designed to test competing hypotheses about the nature of self-

control, 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

1 These researchers also showed that an illusion of controllability

eliminated this effect. From our perspective, this implies that part of the

stress involves the threat or anticipation of continued aversive stimula-

tion, 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 self-

regulation 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 exer-

tions 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 opera-

tion ( "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 do-

main-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 con-

tinue 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 re-

sisting 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 distinctive foods 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 partic-

ipant 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.

Unbeknownst to the participant, both these test figures had been prepared

so as to be impossible to solve.

The experimenter then left the room and timed how long the 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 ob-

served all participants during the eating phase to ascertain that

they ate the stipulated food and avoided the other. All partici-

pants 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 some-

thing other than persistence, such as speed. That is, the interpre-

tation 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 one-

way 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 admin-

istered 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 vari-

able. 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 choco-

late (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 in-

creased 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 circum-

Condition  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.

2 As 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 proj-

ect. 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 self-

regulation. 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-regula-

tion. The present results were directly opposite to that predic-

tion. 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 mak-

ing 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 re-

sisting 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 self-

regulation. 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 stam-

ina 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 con-

trol, 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 Experi-

ment 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 behav-

ior. 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) be-

havior as freely chosen, and many studies have replicated these

effects.

Our interest was not in the attitudinal consequences of count-

erattitudinal 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 re-

source. As an index of this ego depletion, we measured frustra-

tion 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 engag-

ing 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 responsi-

bility 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 in-

crease, 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; Coo-

per & Fazio, 1984; Festinger, 1957; Linder et al., 1967), but it

should still deplete the self to some degree because it still in-

volves 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 stu-

dents (25 male, 14 female). They participated in individual sessions.

They were randomly assigned among four experimental treatment condi-

tions: counterattitudinal choice, counterattitudinal no choice, proattitudi-

nal choice, and no speech (control). To ensure that the issue was person-

ally relevant to all participants, we excluded 8 additional potential parti-

cipants who were either graduating seniors or who were on full

scholarship, because preliminary testing 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 persua-

sion. 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 tuition increase 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  pro-

tuition raise and anti-tuition raise.  Participants in the n0-choice (count-

erattitudinal) 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 condi-

tions 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 experi-

menter 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. Accord-

ingly, the next part of the experiment would contain a measure of prob-

lem-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 Experi-

ment 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 ma-

nipulation 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 condi-

tions, 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 va-

lence 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 persis-

tence were not due to differential moods engendered by the

manipulations.

Discussion

Results

Manipulation check.  The final questionnaire asked partici-

pants (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 count-

erattitudinal-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 read-

ing an alternative speech to the one suggested by the experi-

menter, 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 pre-

sented 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 surpris-

ingly, the two choice conditions did not differ significantly from

each other.

The results supported the ego depletion hypothesis and sug-

gest that acts of choice draw on the same limited resource used

for self-control. Participants who agreed to make a counterattitu-

dinal 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 partici-

pants). Thus, taking responsibility for a counterattitudinal be-

havior 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 proattitudi-

nal behavior condition. These people should not have experi-

enced any dissonance, yet they showed significant reductions

in persistence on unsolvable problems. Dissonance is marked

3 The differences between the control condition and the two high-

choice conditions failed to reach significance if we used the error term

from the ANOVA as the pooled variance estimate. The proattitudinal-

choice 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 con-

dition 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 responsi-

ble for ego depletion, because we found almost identical evi-

dence 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 counteratti-

tudinal behavior under low choice persisted just as long as no-

speech 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 weak-

ened by prior exercise of volition, either in the form of resisting

temptation (Experiment 1 ) or making a responsible choice (Ex-

periment 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 un-

doubtedly 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 recog-

nized 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 manipu-

lation of ego depletion involved affect regulation (i.e., control-

ling 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 (hu-

morous) 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 self-

regulation. 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) under-

graduates who took part in connection with introductory psychology

requirements. They participated in individual sessions and were ran-

domly 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 proce-

dure 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 experi-

menter 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 featur-

ing the comedian Robin Williams. The others saw an excerpt from the

film  Terms of Endearment,  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 com-

pleting 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 partici-

pants to rate how effortful it had been to comply with the

instructions for watching the video clip. Participants in the sup-

press-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 concen-

trate 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 sig-

nificantly worse than participants in the no-regulation condition

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 emo-

tional 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 detri-

mental 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 seem-

ingly account for the results of Experiment 3. In this study, an

act of self-regulation--stifling one'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 hypothe-

sis of ego depletion. Experiment 4 was designed to provide

converging evidence using quite different procedures. Also, Ex-

periment 4 was designed to complement Experiment 2 by re-

versing 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 sub-

sequent 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., continuing was active and quitting was passive). The other

situation was the reverse, in which a positive move was required

to terminate whereas continuing was 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 findings of 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-option effect is an important

possible consequence of the limited resources that the self has

for volitional response. 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 re-

sponding 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 vol-

unteered 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 de-

plete 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 partici-

pants 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 instruc-

tions 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 over-

ride 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 fe-

maies) 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 moti-

vated 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 televi-

sion program  (Saturday Night Live).  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 parti-

cipants 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, parti-

cipants 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 as-

signed to the difficult-rules condition reported having to concen-

trate 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 concen-

trate more than participants in the no-depletion condition, which

should have resulted in participants in the ego-depletion condi-

tion using more ego strength than participants in the no-deple-

tion 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 com-

pared 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 deple-

tion) and what participants did to quit watching the movie (ac-

tive 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-

4 Of 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 dura-

tion 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 stop-

ping 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 indi-

cated that choice depleted the ego. It might seem contradictory

to suggest that passive choice does not draw on the same re-

source, 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 implic-

itly have the option of refusing to make the assigned counteratti-

tudinal 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 un-

related 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, responsi-

ble 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 con-

sented 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 un-

der 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 particu-

lar behavior chosen, that depleted the self and reduced subse-

quent persistence. Regardless of whether the speech was consis-

tent 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 explana-

tion that ego depletion actually improved subsequent self-regu-

lation, 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 self-

regulation 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 re-

sponding 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 self-

control (Study 1 ), that making a responsible decision impaired

subsequent self-control (Study 2), that self-control lowered per-

formance 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 possibility that results could be artifacts of a particu-

lar 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 voli-

tion. 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 experi-

ments. 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 choos-

ing 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 self-

regulation instead of a sign of self-regulation failure. This inter-

pretation 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 unwilling to 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 subsequent tasks.

Although there is no evidence for such a view, it could reason-

ably 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 active-

quit 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 proatti-

tudinal speech were the same as the effects of agreeing to make

a counterattitudinal speech, whereas an equity calculation would

almost surely assume that agreeing to make the counterattitudi-

nal 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 carry-

over 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 augmenting the cogni-

tive and interpersonal aspects of self with an appreciation of

this volitional resource. The operation Of the volitional, agentic,

controlling aspect of the self may require an energy model.

Moreover, this resource appears to be quite surprisingly lim-

ited. In Study 1, for example, a mere 5 rain of resisting tempta-

tion 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 nox-

ious or strenuous, would seriously deplete some important as-

pect 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 relinquish or 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 automati-

cally 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 con-

serve this resource.

It is also conceivable that ego depletion is central to various

patterns of psychological difficulties that people experience, es-

pecially ones that require unusual exertions of affect regulation,

choice, or other volition. Burnout, learned helplessness, and

similar patterns of pathological passivity might have some ele-

ment 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 re-

plenish. On the darker side, it may be that highly controlled

people who seem to snap and abruptly perpetrate acts of vio-

lence 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 impli-

cations lie far beyond the present data, however.

We acknowledge that we do not have a clear understanding of

the nature of this resource. We can say this much: The resource

functions to connect abstract principles, standards, and inten-

tions 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 implausible that ego deple-

tion 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 evi-

dence about ego depletion patterns deserve reiterating. On the

negative side, these results point to a potentially serious con-

straint on the human capacity for control (including self-con-

trol) and deliberate decision making. On the positive side, they

point toward a valuable and powerful feature of human

self hood.

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Received November 11, 1996

Revision received June 10, 1997

Accepted June 16, 1997 •