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Psychological Science
24(5) 776 –781
© The Author(s) 2013
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DOI: 10.1177/0956797612459659
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Millions of college and graduate-school applicants take
standardized tests of academic ability such as the SAT and
GRE each year on the premise that these tests capture
variability in a stable cognitive capacity that is predictive
of educational and professional success. Although these
tests are designed to be minimally coachable (Powers
& Rock, 1999), their role in gating access to competitive
schools has generated a multibillion-dollar test-prep
industry. In a similar fashion, although on a smaller scale,
broadly predictive psychological measures such as work-
ing memory capacity (WMC) have traditionally been
thought to capture fixed abilities but have recently become
the focus of training studies aimed at testing plasticity in
fundamental cognitive capacities (Klingberg, 2010).
As research into enhancing cognitive function pro-
ceeds, it is important to address not only which specific
capacities can be improved, but also which mechanisms
underlie observed changes in cognitive capacities.
Although it is unsurprising that practicing for the GRE or
a WMC task could improve performance on these tests,
rigorous demonstrations of enhanced capacity require
mechanistic accounts of improvements that cannot be
explained by task-specific learning or strategies (Jaeggi,
Buschkuehl, Jonides, & Perrig, 2008).
Training studies frequently target a single ability
(Klingberg, 2010), yet performance might be enhanced
more generally by interventions that target a cognitive
process underlying performance in a variety of contexts
(Slagter, Davidson, & Lutz, 2011). The ability to attend to
a task without distraction constitutes one such ability.
Indeed, mind wandering—defined as a shift of attention
from a task to unrelated concerns—is associated with
impaired performance on a wide variety of measures,
including WMC, fluid intelligence, and SAT performance
(Mrazek, Smallwood, Franklin, et al., 2012). Unfortunately,
little progress has been made in establishing empirically
validated strategies that dampen mind wandering’s dis-
ruptive influence. A notable exception is the recent find-
ing that mind wandering during a vigilance task can be
Corresponding Author:
Michael D. Mrazek, Department of Psychological and Brain Sciences,
University of California, Santa Barbara, CA 93106
E-mail: mrazek@psych.ucsb.edu
Performance
2013
Mindfulness Training Improves Working
Memory Capacity and GRE Performance
While Reducing Mind Wandering
Michael D. Mrazek, Michael S. Franklin, Dawa Tarchin Phillips,
Benjamin Baird, and Jonathan W. Schooler
University of California, Santa Barbara
Abstract
Given that the ability to attend to a task without distraction underlies performance in a wide variety of contexts,
training one’s ability to stay on task should result in a similarly broad enhancement of performance. In a randomized
controlled investigation, we examined whether a 2-week mindfulness-training course would decrease mind wandering
and improve cognitive performance. Mindfulness training improved both GRE reading-comprehension scores and
working memory capacity while simultaneously reducing the occurrence of distracting thoughts during completion
of the GRE and the measure of working memory. Improvements in performance following mindfulness training were
mediated by reduced mind wandering among participants who were prone to distraction at pretesting. Our results
suggest that cultivating mindfulness is an effective and efficient technique for improving cognitive function, with wide-
reaching consequences.
Keywords
mindfulness, mind wandering, working memory capacity, reading comprehension, attention, cognitive ability, reading,
memory
Received 4/4/12; Revision accepted 7/16/12
Research Report
Mindfulness Improves Cognitive Performance 777
reduced by brief mindfulness exercises (Mrazek,
Smallwood, & Schooler, 2012), which suggests that mind-
fulness training may be a promising strategy for improv-
ing task focus and performance.
Sages have long advocated the value of cultivating an
ability to mindfully focus on the here and now, and con-
verging scientific evidence has begun to corroborate this
view. Mindfulness training prevents the deterioration of
WMC during periods of high stress (Jha, Stanley, Kiyonaga,
Wong, & Gelfand, 2010), enhances attention (Brefczynski-
Lewis, Lutz, Schaefer, Levinson, & Davidson, 2007; MacLean
et al., 2010; Slagter et al., 2007), improves visuospatial pro-
cessing efficiency (Kozhevnikov, Louchakova, Josipovic, &
Motes, 2009), increases backward digit memory span
(Chambers, Lo, & Allen, 2008), and serves as a useful treat-
ment for a large and growing list of medical conditions
(Ludwig & Kabat-Zinn, 2008). In this randomized con-
trolled investigation, we examined whether mindfulness
training was more effective than a control program (nutri-
tion training) in (a) improving reading comprehension,
which is among the most important skills in modern soci-
ety; (b) enhancing performance on the WMC measure most
highly predictive of performance across a range of con-
texts; and (c) reducing distracting thoughts during the
completion of both a reading-comprehension measure
(based on the GRE) and the WMC measure. We also
hypothesized that improvements in WMC and GRE perfor-
mance would be mediated by a reduction in mind
wandering.
Method
Forty-eight undergraduate students (14 male, 34 female;
mean age = 20.83 years, SD = 2.05) were randomly
assigned to either a mindfulness class (n = 26) or a nutri-
tion class (n = 22) using a mixed factorial pretest-posttest
design. Classes met for 45 min four times a week for 2
weeks and were taught by professionals with extensive
teaching experience in their respective fields.
The mindfulness class emphasized the physical posture
and mental strategies of focused-attention meditation
(Dorje, 2009; Lutz, Slagter, Dunne, & Davidson, 2008). It
required participants to integrate mindfulness into their
daily activities and to complete 10 min of daily meditation
outside of class. During class, participants sat on cushions
in a circle. Each class included 10 to 20 min of mindful-
ness exercises requiring focused attention to some aspect
of sensory experience (e.g., sensations of breathing, tastes
of a piece of fruit, or sounds of an audio recording).
Participants shared their experiences with the class
and received personalized feedback from the instructor.
Class content was designed to provide a clear set of strate-
gies for and a conceptual understanding of how to
practice mindfulness. Classes focused on (a) sitting in
an upright posture with legs crossed and gaze lowered,
(b) distinguishing between naturally arising thoughts and
elaborated thinking, (c) minimizing the distracting quality
of past and future concerns by reframing them as mental
projections occurring in the present, (d) using the breath
as an anchor for attention during meditation, (e) repeat-
edly counting up to 21 consecutive exhalations, and (f)
allowing the mind to rest naturally rather than trying to
suppress the occurrence of thoughts.
This training has many similarities to, but also some key
differences from, the widely researched Mindfulness Based
Stress Reduction (MBSR) program (Grossman, Niemann,
Schmidt, & Walach, 2004). For instance, both programs
introduce a secular version of mindfulness over the course
of eight small-group sessions, require participants to prac-
tice mindfulness outside of class, and cultivate mindfulness
of multiple sensory modalities. However, the mindfulness
training used in this study differed from MBSR in that it
occurred over 2 weeks rather than 8, required considerably
less time spent in formal daily practice outside of class, and
involved a slightly different presentation of techniques for
developing mindfulness.
The nutrition program covered fundamental topics in
nutrition science and applied strategies for healthy eating.
To match the time commitment of the daily meditation
requirement, we required participants assigned to the
nutrition program to log their daily food intake, but they
were not required to make any specific dietary changes.
Within a week before and within a week after classes,
participants completed in a counterbalanced order a WMC
task and a verbal-reasoning section from the GRE (20 min
allotted for completion), which we modified by excluding
vocabulary-focused questions. Given this modification,
the GRE measure is best interpreted as an assessment of
reading comprehension. Accuracy on the GRE was calcu-
lated as the proportion of total questions answered cor-
rectly. We used two versions of the verbal GRE measure
that were matched for difficulty and counterbalanced
within each condition. There was no significant difference
in accuracy on the two versions at pretesting, F(1, 46) =
0.114, p = .737, which indicated that the two versions
were well-matched for difficulty.
WMC was assessed via the widely used operation span
task (OSPAN). Relative to other measures of WMC, com-
plex span tasks such as the OSPAN are highly predictive
of an individual’s performance across a range of contexts
(Unsworth, Heitz, Schrock, & Engle, 2005). In this com-
plex span task, presentations of to-be-remembered stimuli
were alternated with an unrelated processing task (i.e.,
participants had to verify the accuracy of presented equa-
tions). In each of 15 trials, the to-be-remembered items
were sets of 3 to 7 letters chosen from a pool of 12 letters
and presented for 250 ms each. At the end of each trial,
participants selected the presented items in the order in
which they had appeared. Stimuli for the OSPAN were
chosen randomly from a list of letters and equations,
778 Mrazek et al.
which ensured that participants would not encounter the
same pattern of stimuli across the two testing sessions.
Following standard procedures, we defined accuracy rates
less than 85% on the unrelated processing task as an
exclusion criterion (counting as errors any responses that
exceeded the mean latency for 15 practice items by more
than 2.5 standard deviations; Unsworth et al., 2005); how-
ever, no participants met this criterion and had to be
excluded. WMC was calculated as the proportion of total
letters recalled across all trials.
Mind wandering during the OSPAN was measured with
a widely used retrospective measure of task-unrelated
thought administered after the OSPAN (Matthews et al.,
1999). During the GRE, mind wandering was measured
with both thought sampling and participants’ self-reports
of instances of mind wandering. Eight thought-sampling
probes were presented at unpredictable quasirandom
intervals and asked participants to indicate the extent to
which their attention was focused on the task or on task-
unrelated concerns, using a 5-point Likert scale (1 = com-
pletely on task; 2 = mostly on task; 3 = both on the task and
on unrelated concerns; 4 = mostly on unrelated concerns;
5 = completely on unrelated concerns). Participants also
used a written form to count instances in which they
caught their minds wandering independently of thought
probes. Detailed descriptions of these methodologies are
available in prior work (Mrazek et al., 2011; Schooler
et al., 2011).
Several aspects of the methodological design, particu-
larly the control group, allow for confidence that any
observed improvements in task focus and performance
were a direct result of the mindfulness training rather than
a confounding element of the mindfulness program or the
research design. All participants understood that they
would be randomly assigned to a training program, which
eliminated any self-selection effects between conditions.
Both classes were taught by expert instructors, were com-
posed of similar numbers of students, were held in com-
parable classrooms during the late afternoon, and used a
similar class format, including both lectures and group dis-
cussions. Furthermore, all participants were recruited
under the pretense that the study was a direct comparison
of two equally viable programs for improving cognitive
performance, which minimized motivation and placebo
effects. Finally, we minimized experimenter expectancy
effects by testing participants in mixed-condition groups
in which nearly all task instructions were provided by
computers.
Results
Accuracy on the verbal GRE measure at pretesting was
correlated with participants’ SAT reading-comprehension
scores from when they had applied to college (r = .446,
p = .003), which provided support for the ecological
validity of this laboratory measure. For each performance
and mind-wandering variable, a mixed-model analysis of
variance (ANOVA) was conducted with condition (mind-
fulness training vs. nutrition training) entered as a
between-subjects factor and testing session (before train-
ing vs. after training) entered as a within-subjects factor.
Prior to training, there were no significant differences in
GRE accuracy (p = .98), in WMC (p = .48), or in probe-
caught (p = .41), self-caught (p = .34), or retrospectively
self-reported (p = .07) mind wandering. We found a sig-
nificant main effect of session only for WMC, F(1, 46) =
17.102, p < .001 (all other ps > .05).
More important, the condition-by-session interaction
was significant for each of the performance and mind-
wandering variables. Relative to the nutrition program,
mindfulness training led to improved accuracy on the
GRE, F(1, 46) = 5.609, p = .02; higher WMC, F(1, 46) =
3.954, p = .05; and less probe-caught mind wandering,
F(1, 46) = 8.241, p = .006; self-caught mind wandering,
F(1, 46) = 3.956, p = .05; and retrospectively self-reported
mind wandering during testing, F(1, 46) = 5.337, p = .03.
Follow-up t tests indicated that the mindfulness training
led to significant improvements in performance and
reductions in mind wandering across all variables (ps <
.05; Fig. 1). Using standardized score conversion proce-
dures for the GRE test, the change in GRE accuracy from
mindfulness training led to an average improvement anal-
ogous to 16 percentile points.
Given that only participants whose minds had wan-
dered at pretesting could measurably improve their focus,
we next examined whether improvement in WMC and
GRE performance following mindfulness training was
mediated by reduced mind wandering specifically among
participants who were prone to mind wandering at pre-
testing. Following Preacher, Rucker, and Hayes (2007), we
ran a test of moderated mediation examining whether the
effect of condition on change in performance (an average
of changes in the proportion of correct responses on the
WMC and GRE measures) was mediated by change in
mind wandering (an average of z-score-standardized
changes in probe-caught and retrospectively self-reported
mind wandering) specifically for participants with high
levels of baseline mind wandering (an average of z-score-
standardized probe-caught and retrospectively self-
reported mind wandering at pretesting; see Table 1).
Following standard procedures, we examined the indi-
rect effect of condition on change in performance through
change in mind wandering at three conditional values of
baseline mind wandering (corresponding to the mean, 1
SD above the mean, and 1 SD below the mean). The indi-
rect effect was significant only at 1 standard deviation
above the mean (Table 2). Change in mind wandering
therefore significantly mediated the effect of mindfulness
training on change in performance among participants
who exhibited a tendency to mind-wander at pretesting.
Mindfulness Improves Cognitive Performance 779
0
0.1
0.2
0.3
0.4
0.5
0.6
Nutrition Mindfulness
Accuracy on Verbal GRE
*
Pretest
Posttest
40
45
50
55
60
65
70
Nutrition Mindfulness
Working Memory Capacity
*
Pretest
Posttest
0.0
0.5
1.0
1.5
2.0
2.5
Nutrition Mindfulness
Probe-Caught TUTs
*
Pretest
Posttest
0
2
4
6
8
10
12
Nutrition Mindfulness
Self-Caught TUTs
*
Pretest
Posttest
0.0
0.2
0.4
0.6
0.8
1.0
1.2
1.4
1.6
1.8
2.0
Nutrition Mindfulness
Self-Reported TUTs
*
Pretest
Posttest
ab
c
e
d
Fig. 1. Results. The graphs show results for each of the following study variables as a func-
tion of condition and testing session: (a) accuracy (proportion of correct responses) on the GRE,
(b) working memory capacity (WMC), (c) probe-caught TUTs (task-unrelated thoughts), (d) retro-
spectively self-reported TUTs during performance of the WMC measure, and (e) self-caught TUTs
during performance of the GRE. Error bars represent standard errors of the mean. Asterisks indicate
significant differences between the two testing sessions (p < .05).
780 Mrazek et al.
This finding demonstrates that, relative to nutrition train-
ing, which did not cause changes in performance or mind
wandering, the mindfulness training led to an enhance-
ment of performance that was mediated by reduced mind
wandering among participants who had been prone to
mind wandering at pretesting.
Discussion
The present study demonstrates that a 2-week mindfulness-
training program can elicit increased WMC and superior
reading comprehension on the GRE. The practice of
mindfulness encouraged in our intervention entailed pro-
moting a persistent effort to maintain focus on a single
aspect of experience, particularly sensations of breathing,
despite the frequent interruptions of unrelated percep-
tions or personal concerns. The present findings suggest
that when this ability to concentrate is redirected to a
challenging task, it can prevent the displacement of cru-
cial task-relevant information by distractions. At least for
people who struggle to maintain focus, our results suggest
that the enhanced performance derived from mindfulness
training results from a dampening of distracting thoughts.
Our findings of reduced mind wandering are consis-
tent with recent accounts that mindfulness training leads
to reduced activation of the default network, a collection
of brain regions that typically show greater activation at
rest than during externally directed cognitive tasks. Both
long-term meditators and individuals who have com-
pleted 2 weeks of mindfulness training show reduced
activation of the default network (Brefczynski-Lewis et al.,
2007; Brewer et al., 2011; Tang et al., 2009). Given that the
default network has been repeatedly associated with
markers of mind wandering (Christoff, Gordon, Smallwood,
Smith, & Schooler, 2009; Mason et al., 2007), future
research should directly test whether mindfulness training
reduces mind wandering by dampening activation of the
default network.
Training studies typically involve extensive practice of
a task that targets a specific cognitive ability. Often, the
goal of these studies is to demonstrate a transfer of
improvement beyond the trained task to an unpracticed
task measuring the same ability, thereby ruling out expla-
nations based on task-specific learning or strategies
(Klingberg, 2010). In principle, the strongest evidence for
enhanced cognitive ability is therefore derived from stud-
ies that use a training task with little resemblance to the
outcome measure. From this perspective, our use of mind-
fulness training in the present investigation allowed us to
provide a rigorous demonstration of cognitive enhance-
ment that cannot be attributed to overlap between train-
ing and testing contexts.
Counter to the long-standing assumption that mental
aptitude is largely fixed across the life span, recent work
has indicated that extensive practice on tests of WMC can
generalize to improvements in IQ (Jaeggi et al., 2008) and
that IQ can either improve or deteriorate throughout ado-
lescence (Ramsden et al., 2011). Although it is likely that
a variety of mechanisms contribute to these changes, the
present demonstration that mindfulness training improves
cognitive function and minimizes mind wandering sug-
gests that enhanced attentional focus may be key
to unlocking skills that were, until recently, viewed as
immutable.
Table 1. Moderated-Mediation Results
Predictor βSE Statistical test p
Predicting the mediator
Constant 1.124 0.363 t(46) = 3.097 .003
Condition −0.734 0.225 t(46) = −3.257 .002
Predicting the outcome variable
Constant −0.177 0.196 z = −0.899 .374
Condition 0.183 0.123 z = 1.490 .144
TUT change −0.126 0.080 z = 1.566 .125
TUT baseline 0.027 0.077 z = 0.352 .727
TUT Change × TUT Baseline −0.178 0.058 z = −3.079 .004
Note: In the moderated-mediation model, change in mind wandering (task-unrelated thought,
or TUT) was the mediator variable, baseline mind wandering was the moderator variable, and
change in performance was the outcome variable.
Table 2. Mediation Effects According to Baseline Levels of
Mind Wandering
TUT baseline
Indirect
effect SE z p
–0.820 (1SD below the mean) –0.015 0.071 –0.208 .8356
0.000 (mean) 0.092 0.068 1.360 .1740
0.820 (1 SE above the mean) 0.200 0.095 2.108 .0351
Note: The table presents results from the model of the effect of condi-
tion on performance as mediated by mind wandering (task-unrelated
thought, or TUT).
Mindfulness Improves Cognitive Performance 781
Declaration of Conflicting Interests
The authors declared that they had no conflicts of interest with
respect to their authorship or the publication of this article.
Funding
M. D. Mrazek, M. S. Franklin, D. T. Phillips, and J. W. Schooler
are supported through U.S. Department of Education Grant
R305A110277 awarded to J. W. Schooler. B. Baird is supported
by a National Science Foundation Graduate Research Fellowship
under Grant DGE-0707430. The content of this article does not
necessarily reflect the position or policy of the U.S. government,
and no official endorsement should be inferred.
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