Content uploaded by Sean H K Kang
Author content
All content in this area was uploaded by Sean H K Kang on Feb 05, 2018
Content may be subject to copyright.
Content uploaded by Sean H K Kang
Author content
All content in this area was uploaded by Sean H K Kang on Apr 13, 2016
Content may be subject to copyright.
Policy Insights from the
Behavioral and Brain Sciences
2016, Vol. 3(1) 12 –19
© The Author(s) 2016
DOI: 10.1177/2372732215624708
bbs.sagepub.com
Instructional Strategies
Tweet
For durable learning, space out your review of the material
over time; back-to-back repetitions are ineffective.
Key Points
The timing or arrangement of review/practice affects
learning.
Practice is more effective when spaced out over time,
instead of massed or grouped together (equating total
practice time).
Spaced practice enhances memory, problem solving,
and transfer of learning to new contexts.
Spaced practice offers great potential for improving
students’ educational outcomes.
Introduction
Every few years, when the results of international assessments
of students’ mathematics, science, and reading proficiency
(e.g., Trends in International Mathematics and Science Study,
Programme for International Student Assessment) are released,
there is renewed consternation that American students lag
behind their peers in other countries. Many factors have been
proposed to explain the differences in educational outcomes
among participating countries, including cultural attitudes
toward education (e.g., Jensen, Hunter, Sonnemann, & Burns,
2012; Pearson, 2012). One question debated in the United
States for decades is whether children spend enough time in
school (Barrett, 1990). Although the number of school days per
year for American children is relatively low, compared to many
other countries, in terms of total instruction hours from primary
through lower secondary education, the United States ranks
among the highest (Organisation for Economic Co-operation
and Development, 2014). What counts as official instruction
time, however, varies across countries (and across states within
the United States). Also, whether the time is used as intended
(for teaching, as opposed to performing administrative or class-
room management tasks) and how much additional time is
spent on schoolwork outside of school (e.g., homework, after-
school tutoring) clearly do matter as well.
Independent of whether sufficient time is devoted to aca-
demics (both inside and outside of school), another perhaps
more tractable issue (and the focus of this article) is how
624708BBSXXX10.1177/2372732215624708Policy Insights from the Behavioral and Brain SciencesKang
research-article2016
1Dartmouth College, Hanover, NH, USA
Corresponding Author:
Sean H. K. Kang, Department of Education, Dartmouth College, 210
Raven House, HB 6103, Hanover, NH 03755, USA.
Email: Sean.H.Kang@dartmouth.edu
Spaced Repetition Promotes Efficient and
Effective Learning: Policy Implications for
Instruction
Sean H. K. Kang1
Abstract
Concern that students in the United States are less proficient in mathematics, science, and reading than their peers in other
countries has led some to question whether American students spend enough time in school. Instead of debating the amount
of time that should be spent in school (and on schoolwork), this article addresses how the available instructional time might
be optimally utilized via the scheduling of review or practice. Hundreds of studies in cognitive and educational psychology
have demonstrated that spacing out repeated encounters with the material over time produces superior long-term learning,
compared with repetitions that are massed together. Also, incorporating tests into spaced practice amplifies the benefits.
Spaced review or practice enhances diverse forms of learning, including memory, problem solving, and generalization to new
situations. Spaced practice is a feasible and cost-effective way to improve the effectiveness and efficiency of learning, and
has tremendous potential to improve educational outcomes. The article also discusses barriers to adopting spaced practice,
recent developments, and their possible implications.
Keywords
research-based instructional strategies, spaced/distributed practice, testing, learning, education
Kang 13
instructional activities are scheduled. Within the available
time, can instruction and related learning activities be
arranged in a manner that is optimal for learning? Put differ-
ently, is student learning affected by the timing of academic
activities? A large body of research from cognitive and edu-
cational psychology suggests an affirmative answer to both
questions. Repeated encounters with to-be-learned material
that are spaced out in time (as opposed to recurring back-to-
back) are an effective way to foster learning that is long last-
ing. Incorporating spaced repetitions into existing educational
practice is feasible and has great potential to produce gains to
learning without requiring added resources (time or money).
The Spacing Effect
Most people know from personal experience that if one is
trying to learn something well—be it a set of facts, concepts,
skills, or procedures—a single exposure is usually inade-
quate for good long-term retention. We are all familiar with
the adage “practice makes perfect.” But what is less obvious
is that the timing of the practice (when it occurs) matters a
great deal: Having the initial study and subsequent review or
practice be spaced out over time generally leads to superior
learning than having the repetition(s) occur in close temporal
succession (with total study time kept equal in both cases).
This phenomenon is called the spacing effect (sometimes
also referred to as the benefit of distributed practice) and
was first observed by researchers over a century ago
(Ebbinghaus, 1885/1913). Since that time, literally hundreds
of experiments by cognitive psychologists have demon-
strated the advantage of spaced/distributed over massed
practice (Cepeda, Pashler, Vul, Wixted, & Rohrer, 2006), and
a recent comprehensive review of the utility of various learn-
ing strategies awarded distributed practice one of the highest
ratings based on the available research evidence (Dunlosky,
Rawson, Marsh, Nathan, & Willingham, 2013). Figure 1
shows a commonly used design for studying the spacing
effect when there is a single review opportunity.
Spaced Practice Benefits Memory
Probably the most robust effects of spacing occur in improved
rote memory for the studied material. Across 254 studies
comparing massed versus spaced practice on later memory
for verbal information (e.g., words, sentences, facts, pas-
sages), overall, spaced practice dominated massed practice
in recall performance (Cepeda et al., 2006). In one early
study, to illustrate a specific instance, college students were
asked to learn the Athenian Oath (Gordon, 1925). One group
of students heard the oath read 6 times in a row; another
group heard the oath 3 times on 1 day and 3 more times 3
days later. The students recalled as much as they could
immediately after hearing the oath for the sixth time and
again 4 weeks later. On the immediate test, the group that
received massed repetition recalled slightly more than the
group that received spaced repetition. But on the delayed test
4 weeks later, the spaced group clearly outperformed the
massed group. While massed practice might appear more
effective than spaced practice in the short term, spaced prac-
tice produces durable long-term learning (see Rawson &
Kintsch, 2005, for similar findings regarding rereading of
text passages on immediate vs. delayed recall).
A number of theories may explain the benefit of spaced
practice for long-term retention (Toppino & Gerbier, 2014).
According to one prominent theory, repeating an item poten-
tially reminds the learner of its prior occurrence, which
prompts retrieving the previous presentation of the item, a
process that enhances memory (e.g., Wahlheim, Maddox, &
Jacoby, 2014; the next section elaborates on the effects of
retrieving from memory). Massed repetition eliminates the
retrieval process—there is no need to retrieve from memory
because the same item was just presented. Another theory
emphasizes the study/learning context (i.e., what surrounds
an event, from the external environment to an individual’s
mental state). With spaced repetitions, the context that gets
encoded in memory with each presentation of an item is
likely to be more variable (compared with massed repetitions
that are close together in time and context); the variable con-
texts that are stored in memory then serve as more effective
cues for subsequent retrieval of the item (e.g., Glenberg,
1979). Deficient processing of massed repetitions is yet
another theory. When a current item is the same as one that
was just presented, the redundancy reduces attention (e.g.,
Magliero, 1983). The different theories are not mutually
exclusive, and multiple mechanisms may act in concert to
yield the memory advantage produced by spaced practice.
Few would argue that memorizing instructional content,
so as to be able to reproduce the information verbatim from
memory, is the ultimate goal of education. Nonetheless,
acquiring foundational knowledge and being able to quickly
access relevant information from memory are often prerequi-
sites for higher order learning and reasoning. For instance,
remembering arithmetic facts (e.g., times table) is a critical
part of mathematical skill learning, and a transition from cal-
culation to direct memory retrieval of the answer allows
more efficient problem solving (e.g., Siegler, 1988). Spaced
Figure 1. The typical experimental procedure for examining the
spacing effect.
14 Policy Insights from the Behavioral and Brain Sciences 3(1)
practice promotes not only accurate recall of multiplication
facts in children (Rea & Modigliani, 1985) but also faster
retrieval of target responses (Rickard, Lau, & Pashler, 2008).
Also, possessing adequate prior knowledge can facilitate
subsequent learning and comprehension (e.g., Kalyuga,
2007; Mayer, 1977). In short, spaced practice can improve
students’ memory for essential facts and concepts, which in
turn facilitates more complex learning and problem solving.
Testing + Spacing = Spaced Retrieval Practice
In a recent issue of this journal, Benjamin and Pashler (2015)
argued that testing can be a valuable educational tool for pro-
moting learning (see also reviews by Carpenter, 2012; Karpicke
& Grimaldi, 2012; Roediger & Butler, 2011). In brief, testing
(or practicing retrieval from memory, relative to just rereading
the material) boosts learning in various ways: improved mem-
ory for the tested information (e.g., Kang, McDermott, &
Roediger, 2007), slowed forgetting (e.g., Carpenter, Pashler,
Wixted, & Vul, 2008), transfer of learning to new situations
(e.g., Butler, 2010), generalization to new examples (e.g.,
Kang, McDaniel, & Pashler, 2011), potentiated subsequent
learning (e.g., Arnold & McDermott, 2013), and augmented
learner metacognition (e.g., Soderstrom & Bjork, 2014).
Testing’s benefits are not limited to formal tests. Many infor-
mal ways of testing engage the same kinds of beneficial pro-
cesses, and these include using flashcards when studying (e.g.,
Kornell, 2009) and using “clickers” in class to record students’
responses to the teacher’s questions (e.g., Anderson, Healy,
Kole, & Bourne, 2013). The review of learning strategies cited
earlier (Dunlosky et al., 2013) gave practice testing its highest
utility rating (the same rating that spaced practice received; no
other strategy achieved as high a rating).
Testing or spaced practice, each on its own, confers con-
siderable advantages for learning. But, even better, the two
strategies can be combined to amplify the benefits: Reviewing
previously studied material can be accomplished through
testing (often followed by corrective feedback) instead of
rereading. In fact, many studies of the spacing effect com-
pared spaced against massed retrieval practice, not just
rereading (e.g., Bahrick, 1979; Cepeda, Vul, Rohrer, Wixted,
& Pashler, 2008). Spaced retrieval practice (with feedback)
leads to better retention than spaced rereading. One study
examined how type of review (reread vs. test with feedback),
along with timing of review (massed vs. spaced), affected
eighth-grade students’ retention of history facts (Carpenter,
Pashler, & Cepeda, 2009). On a final test 9 months later,
spaced retrieval practice yielded the highest performance
(higher than spaced rereading).
Is There an Optimal Spacing Lag?
One might assume that if spaced repetitions are more effec-
tive than massed ones, then the longer the lag (between
repetitions), the greater the benefit. The research evidence,
however, suggests that this assumption is too simplistic. A
large experiment examined 10 different lags (the spacing
gap between initial learning and retrieval practice review
ranged from 0 to 105 days) and four different retention
intervals (the final test was administered either 7, 35, 70, or
350 days after the review session; Cepeda et al., 2008).
Retention of trivia facts (the study material) was highest
when the lag was about 10% to 20% of the tested retention
interval (see also Cepeda et al., 2009). In other words, there
is no fixed optimal lag—It depends on the targeted retention
interval. If you want to maximize performance on a test
about 1 week away, then a lag of about 1 day would be opti-
mal; but if you want to retain information for 1 year, then a
lag of about 2 months would be ideal.
This example used only a single review opportunity. What
about situations with multiple opportunities to revisit the
material? Clearly, spacing out the multiple review opportuni-
ties produces better learning than massing them together, but
there is a debate as to whether the multiple reviews should be
equally spaced apart or whether they should occur in an
expanding schedule (i.e., the lag between each successive
review progressively increases; Balota, Duchek, & Logan,
2007). The justification for expanding retrieval practice is
that (a) having the early retrieval attempts occur fairly soon
after initial learning insures a high rate of retrieval success,
and (b) retrieval slows forgetting, so (c) subsequent retrieval
opportunities can be pushed farther apart in time, to ensure
that practice continues to be effortful and not trivial (Landauer
& Bjork, 1978). A study compared expanding and equally
spaced retrieval practice (with corrective feedback), separat-
ing the practice sessions by days or weeks; the expanding
practice schedule yielded higher retention of foreign vocabu-
lary over the extensive training period, suggesting that
expanding practice may especially maintain knowledge over
long periods of time (Kang, Lindsey, Mozer, & Pashler,
2014). Overall, whether expanding practice produces learn-
ing that is superior to equally spaced practice probably
depends on factors such as the difficulty of the to-be-learned
material, the type of review (rereading or retrieval practice),
and the specific time frame (Storm, Bjork, & Storm, 2010).
Spaced Practice Improves Generalization and
Transfer of Learning
This review has so far focused on how spaced practice
improves memory, in part because memory researchers first
observed the spacing effect and also because the majority of
prior studies examined memory. Although acquiring and
retaining knowledge matters in education, a more crucial
objective is transfer, the ability to utilize what was learned to
answer new questions or solve new problems (after all, in
real life the likelihood of encountering material in exactly the
same way as presented during instruction is exceedingly
Kang 15
low). Mere remembering of content is rote learning, focused
on the past; on the contrary, meaningful learning involves
transfer and orients toward the future (Mayer, 2002).
Although the research surrounding the benefits of spaced
practice for more complex kinds of learning is not as exten-
sive as that for memory, some evidence indicates that spac-
ing can enhance meaningful learning that generalizes to new
situations (see Carpenter, Cepeda, Rohrer, Kang, & Pashler,
2012, for a review). In one study, college students attended a
45-min lecture on meteorology and then reviewed the infor-
mation (in a quiz with corrective feedback) either 1 or 8 days
later (Kapler, Weston, & Wiseheart, 2015). On a final test 35
days after the review session, students in the 8-day condition
performed better than those in the 1-day condition not just on
the factual recall questions but also on the questions that
required application of knowledge. Other studies support
spaced practice of mathematics problems (Rohrer & Taylor,
2006) and ecology lessons (Gluckman, Vlach, & Sandhofer,
2014; see also Vlach & Sandhofer, 2012). In addition to
improving mathematics problem solving and science con-
cept learning, spaced practice benefits the long-term learning
of English grammar in adult English-language learners (Bird,
2010). In all cases, the students were not just memorizing
solutions but were instead applying their learning to solve
new problems.
Spacing and Interleaving
One way to space out repetitions is to intersperse other items
in-between repetitions of a given item. For instance, in the
sequence ABCABCABC, two intervening items (e.g., B and
C) come before each recurrence of a given item (e.g., A).
Such an arrangement, in which different kinds of items inter-
mix during practice, is termed interleaved practice. In con-
trast, blocked practice groups the same kinds of items
together during practice (e.g., AAABBBCCC). While an
interleaved schedule does inherently introduce spacing
between repetitions, interleaving is a distinct intervention
from spacing (Rohrer, 2009).
Interleaved practice (relative to blocked practice) benefits
motor skill acquisition, category learning, and mathematics
problem solving (for reviews, see Kang, in press; Rohrer,
2012). Examples from the latter two domains are most
directly related to academic learning.
Sequencing of examples during training affects visual cat-
egory learning (e.g., learning to recognize the painting styles
of different artists or identify different kinds of birds).
Interleaved training (e.g., intermixing paintings by different
artists), relative to blocked training (e.g., consecutively pre-
senting paintings by a given artist), enhances learners’ ability
to accurately classify novel examples (e.g., Kornell & Bjork,
2008; Kornell, Castel, Eich, & Bjork, 2010). Juxtaposition of
the different categories (e.g., artists) during interleaved train-
ing facilitates noticing the differences among the categories
(Kang & Pashler, 2012), which is helpful when the to-be-
learned categories are similar or easily confusable (Carvalho
& Goldstone, 2014). Additional support for the idea that
interleaving promotes discriminative contrast among the cat-
egories comes from a study on learning bird and butterfly
species (Birnbaum, Kornell, Bjork, & Bjork, 2013). The
study also found that temporal spacing could be a factor—
interleaving with more (rather than fewer) intervening items
from other categories, between successive presentations of a
given category, improved learning. Attentional lapses may
also play a role. Mind wandering is more likely during
blocked than interleaved training (Metcalfe & Xu, in press).
Multiple mechanisms may underlie the interleaving advan-
tage: Attention, temporal spacing, and juxtaposing different
categories could jointly contribute to learning.
Interleaved practice also benefits mathematics problem
solving in college students (Rohrer & Taylor, 2007) and ele-
mentary school children (Taylor & Rohrer, 2010). Students
after blocked practice had difficulty discriminating among
the problem types and knowing when to use which formula.
Therefore, similar to category learning, interleaved practice
seems to help learners differentiate among the types of prob-
lems they are learning to solve.
Spaced and Interleaved Practice in the Classroom
Although most studies on spaced or interleaved practice
have been conducted in laboratory settings (for better control
over extraneous variables), students in actual classrooms can
benefit from instructors using these learning strategies (e.g.,
Carpenter et al., 2009; Sobel, Cepeda, & Kapler, 2011). A
few studies were conducted not only in real-world educa-
tional settings but also in the context of a regular curriculum
(i.e., instructional manipulation on course content).
In one classroom-based study, the mathematics home-
work assignments for seventh-grade students were manipu-
lated across 9 weeks (Rohrer, Dedrick, & Burgess, 2014).
Ten mathematics assignments were given out over that
period, each consisting of 12 practice problems. For topics
assigned to blocked practice, all 12 problems in a single
assignment would pertain to that one topic (and no other
assignment would feature that kind of problem). For topics
assigned to interleaved practice, only the first four problems
in the assignment would belong to the current topic; the other
eight problems in the assignment would cover previous top-
ics; also, the remaining eight practice problems pertaining to
the current topic (of the first four problems) would be distrib-
uted across future assignments. That is, the total number of
practice problems devoted to each topic was equal across the
blocked and interleaved conditions (12 practice problems per
topic). The only difference was whether all 12 problems on a
given topic were completed in one assignment or whether
they were spread out across multiple assignments (and there-
fore interleaved with other types of problems). On a surprise
16 Policy Insights from the Behavioral and Brain Sciences 3(1)
test containing novel problems (on the same topics), given 2
weeks after the final homework assignment, the students
were substantially better at solving the types of problems that
had been practiced in an interleaved manner than those under
blocked practice.
Interleaving has strong benefits even when the problem
types were quite different (Rohrer et al., 2014), compared
with the earlier studies on mathematics problem solving
(e.g., Rohrer & Taylor, 2007). Enhanced discrimination
(learning to differentiate the various types of problems) is
not the only explanation for the interleaving advantage.
During interleaved practice, switching among different
problem types may strengthen the association between
a problem type and its strategy, which promotes successful
problem solving. With blocked practice, on the contrary, as
all the problems require the same strategy, the student needs
only focus on executing a given strategy repeatedly, which
might not be as effective in reinforcing the association
between a problem type and its strategy (Rohrer et al., 2014;
see also Rohrer, Dedrick, & Stershic, 2015). A similar study
conducted within a college engineering course found that
spacing out the practice problems on a given topic over 3
weeks produced better performance on the midterm and
final exams than having practice problems on a given topic
assigned only during the week that the topic was taught in
class, which was the standard practice (Butler, Marsh,
Slavinsky, & Baraniuk, 2014).
The studies described above are notable for two reasons.
First, they were conducted within a regular class (middle
school mathematics, college-level engineering). Given that
classroom-based studies tend to be more “noisy,” due to the
lack of control over many variables (e.g., Greene, 2015), the
observed effect of spacing/interleaving is impressive.
Second, the instructors taught the classes as they normally
would have—the topics covered, the lecture content, and the
assessments generally remained the same—suggesting that a
radical overhaul of teaching practice may not be necessary.
Something as simple as reorganizing the homework assign-
ments may be sufficient to produce sizable gains.
Metacognitive Considerations Surrounding
Spaced Practice
A recent survey of college students found that the majority
seemed to be aware that spaced (rather than massed) study
benefits learning (Morehead, Rhodes, & DeLozier, 2016),
yet students report frequently massing (or cramming) their
study before an exam (e.g., Susser & McCabe, 2013). Also,
grade point average (GPA) is correlated with spaced study:
Students with higher GPAs more often report spacing their
study (Hartwig & Dunlosky, 2012). Probably two broad fac-
tors work against students’ greater use of spaced practice as
a study strategy. The first is the forethought or planning
required to space out one’s studying (and the concomitant
discipline needed to follow through on the plan), which helps
explain the discrepancy between an ideal (knowing that
spaced study is beneficial) and actual behavior (ending up
with massed study). The second factor is the subjective sense
of fluency that is often engendered by massed practice,
which can mislead the student into feeling large gains in
learning (Finn & Tauber, 2015). Of course, as in some of the
studies reviewed earlier, these gains do not last. Given that
spaced practice is not the default study habit for most stu-
dents (particularly the ones who are performing poorly), edu-
cators could be especially helpful by structuring their
pedagogy in a way that encourages spaced review.
Capitalizing on Spaced Practice in
Education
Ample evidence supports the utility of spaced practice in
improving educational outcomes. Incorporating spaced prac-
tice into education can be a cost-effective approach—
learning becomes more durable in the same amount of time
(relative to massed practice), and this can lead to future sav-
ings because less time needs to be spent on relearning con-
tent that has been forgotten, leaving more time for other
productive learning activities (e.g., higher order analysis,
application of knowledge). In short, spaced practice enhances
the efficacy and efficiency of learning, and it holds great
promise as an educational tool. Despite over a century of
research findings demonstrating the spacing effect, however,
it does not have widespread application in the classroom.
The spacing effect is “a case study in the failure to apply the
results of psychological research” (Dempster, 1988, p. 627).
Probably (at least) two major obstacles impede greater
implementation of spaced practice in education. When decid-
ing on what instructional techniques to use (and when to use
them), many teachers default to familiar methods (e.g., how
they themselves were taught; Lortie, 1975) or rely on their
intuitions, both less than ideal: Our intuitions about learning
can sometimes be plain wrong, and it would be a waste to
overlook the growing evidence base regarding the effective-
ness of various teaching or learning strategies. A possible
solution is for teacher preparation to increase its focus on the
science of learning (e.g., how the human mind learns, what
factors influence learning, learning strategies, and their rela-
tive efficacy).
The second major hurdle is conventional instructional prac-
tice, which typically favors massed practice. Teaching materials
and aids (e.g., textbooks, worksheets) are usually organized in a
modular way, which makes massed practice convenient. After
presenting a new topic in class, teachers commonly give stu-
dents practice with the topic via a homework assignment. But
aside from that block of practice shortly after the introduction of
a topic, no further practice usually follows, until a review ses-
sion prior to a major exam. What this means for teachers decid-
ing to incorporate spaced practice in their classrooms is that
Kang 17
some planning is required. Complete overhaul of teaching prac-
tice may be difficult, but modifying homework assignments is
probably an achievable target. The classroom-based studies
described earlier (Rohrer et al., 2014; Rohrer et al., 2015) show
how a small change in homework assignments—switching
from having the practice problems in a given assignment on just
one topic, to having a mix of problems pertaining to various top-
ics appearing in each assignment—can dramatically improve
mathematics learning.
Despite the challenges, some relatively recent develop-
ments could contribute to greater adoption of spaced prac-
tice. For instance, the creation of spiral curricula for K-12
classes, in which material is revisited repeatedly over months
and across grades with increasingly deeper levels of com-
plexity, means that schools and teachers will have better
access to teaching resources that incorporate spaced practice
as part of the regular curriculum. Also, increasing use of
computer technology in education (e.g., e-learning, comput-
erized tutors, and learning management systems) could make
it easier for students to engage in spaced retrieval practice
that is adaptive or personalized to their individual needs
(Lindsey, Shroyer, Pashler, & Mozer, 2014). The use of
e-learning platforms might also provide a way to ameliorate
the summer “brain drain.” Assuming a student has already
been engaging in spaced practice over the academic year, a
refresher or review session conducted over the Internet dur-
ing the summer could go a long way in stemming the learn-
ing loss that afflicts many students.
At the end of the 19th century, William James (1899)
exhorted teachers to encourage spaced practice in their
students:
You now see why “cramming” must be so poor a mode of study.
Cramming seeks to stamp things in by intense application
immediately before the ordeal. But a thing thus learned can form
but few associations. On the other hand, the same thing recurring
on different days, in different contexts, read, recited on, referred
to again and again, related to other things and reviewed, gets
well wrought into the mental structure. This is the reason why
you should enforce on your pupils habits of continuous
application. (p. 129)
The advice given over a 100 years ago is still completely
applicable today, bolstered by the added weight of strong sci-
entific evidence. My hope is that educators will embrace cre-
ative ways to foster spaced practice in and outside the
classroom for the benefit of their students’ learning.
Declaration of Conflicting Interests
The author(s) declared no potential conflicts of interest with respect
to the research, authorship, and/or publication of this article.
Funding
The author(s) received no financial support for the research, author-
ship, and/or publication of this article.
References
Anderson, L. S., Healy, A. F., Kole, J. A., & Bourne, L. E. (2013).
The clicker technique: Cultivating efficient teaching and suc-
cessful learning. Applied Cognitive Psychology, 27, 222-234.
Arnold, K. M., & McDermott, K. B. (2013). Free recall enhances sub-
sequent learning. Psychonomic Bulletin & Review, 20, 507-513.
Bahrick, H. P. (1979). Maintenance of knowledge: Questions about
memory we forgot to ask. Journal of Experimental Psychology:
General, 108, 296-308.
Balota, D. A., Duchek, J. M., & Logan, J. M. (2007). Is expanded
retrieval practice a superior form of spaced retrieval? A critical
review of the extant literature. In J. S. Nairne (Ed.), The foun-
dations of remembering: Essays in honor of Henry L. Roediger
III (pp. 83-105). New York, NY: Psychological Press.
Barrett, M. (1990). The case for more school days. The Atlantic
Monthly, 266(5), 78-106. Retrieved from http://www.theatlantic.
com/past/politics/educatio/barr2f.htm
Benjamin, A. S., & Pashler, H. (2015). The value of standard-
ized testing: A perspective from cognitive psychology. Policy
Insights From the Behavioral and Brain Sciences, 2, 13-23.
Bird, S. (2010). Effects of distributed practice on the acquisition
of second language English syntax. Applied Psycholinguistics,
31, 635-650.
Birnbaum, M. S., Kornell, N., Bjork, E. L., & Bjork, R. A. (2013).
Why interleaving enhances inductive learning: The roles of dis-
crimination and retrieval. Memory & Cognition, 41, 392-402.
Butler, A. C. (2010). Repeated testing produces superior transfer of
learning relative to repeated studying. Journal of Experimental
Psychology: Learning, Memory, and Cognition, 36, 1118-1133.
Butler, A. C., Marsh, E. J., Slavinsky, J. P., & Baraniuk, R. G.
(2014). Integrating cognitive science and technology improves
learning in a STEM classroom. Educational Psychology
Review, 26, 331-340.
Carpenter, S. K. (2012). Testing enhances the transfer of learning.
Current Directions in Psychological Science, 21, 279-283.
Carpenter, S. K., Cepeda, N. J., Rohrer, D., Kang, S. H. K., &
Pashler, H. (2012). Using spacing to enhance diverse forms
of learning: Review of recent research and implications for
instruction. Educational Psychology Review, 24, 369-378.
Carpenter, S. K., Pashler, H., & Cepeda, N. J. (2009). Using tests
to enhance 8th grade students’ retention of U.S. history facts.
Applied Cognitive Psychology, 23, 760-771.
Carpenter, S. K., Pashler, H., Wixted, J. T., & Vul, E. (2008).
The effects of tests on learning and forgetting. Memory &
Cognition, 36, 438-448.
Carvalho, P. F., & Goldstone, R. L. (2014). Putting category learn-
ing in order: Category structure and temporal arrangement
affect the benefit of interleaved over blocked study. Memory &
Cognition, 42, 481-495.
Cepeda, N. J., Coburn, N., Rohrer, D., Wixted, J. T., Mozer, M.
C., & Pashler, H. (2009). Optimizing distributed practice:
Theoretical analysis and practical implications. Experimental
Psychology, 56, 236-246.
Cepeda, N. J., Pashler, H., Vul, E., Wixted, J. T., & Rohrer, D.
(2006). Distributed practice in verbal recall tasks: A review and
quantitative synthesis. Psychological Bulletin, 132, 354-380.
Cepeda, N. J., Vul, E., Rohrer, D., Wixted, J. T., & Pashler, H.
(2008). Spacing effects in learning a temporal ridgeline of opti-
mal retention. Psychological Science, 19, 1095-1102.
18 Policy Insights from the Behavioral and Brain Sciences 3(1)
Dempster, F. N. (1988). The spacing effect: A case study in the
failure to apply the results of psychological research. American
Psychologist, 43, 627-634.
Dunlosky, J., Rawson, K. A., Marsh, E. J., Nathan, M. J., &
Willingham, D. T. (2013). Improving students’ learning with
effective learning techniques: Promising directions from cog-
nitive and educational psychology. Psychological Science in
the Public Interest, 14, 4-58.
Ebbinghaus, H. (1913). Memory (H. A. Ruger & C. E. Bussenius,
Trans.). New York, NY: Teachers College, Columbia
University. (Original work published 1885)
Finn, B., & Tauber, S. K. (2015). When confidence is not a signal of
knowing: How students’ experiences and beliefs about process-
ing fluency can lead to miscalibrated confidence. Educational
Psychology Review, 27, 567-586.
Glenberg, A. M. (1979). Component-levels theory of the effects
of spacing of repetitions on recall and recognition. Memory &
Cognition, 7, 95-112.
Gluckman, M., Vlach, H. A., & Sandhofer, C. M. (2014). Spacing
simultaneously promotes multiple forms of learning in chil-
dren’s science curriculum. Applied Cognitive Psychology, 28,
266-273.
Gordon, K. (1925). Class results with spaced and unspaced memo-
rizing. Journal of Experimental Psychology, 8, 337-343.
Greene, J. A. (2015). Serious challenges require serious scholar-
ship: Integrating implementation science into the scholarly dis-
course. Contemporary Educational Psychology, 40, 112-120.
Hartwig, M. K., & Dunlosky, J. (2012). Study strategies of college
students: Are self-testing and scheduling related to achieve-
ment? Psychonomic Bulletin & Review, 19, 126-134.
James, W. (1899). Talks to teachers on psychology: And to students
on some of life’s ideals. New York: Henry Holt.
Jensen, B., Hunter, A., Sonnemann, J., & Burns, T. (2012). Catching
up: Learning from the best school systems in East Asia. Grattan
Institute. Retrieved from http://grattan.edu.au/report/catching-
up-learning-from-the-best-school-systems-in-east-asia/
Kalyuga, S. (2007). Expertise reversal effect and its implica-
tions for learner-tailored instruction. Educational Psychology
Review, 19, 509-539.
Kang, S. H. K. (in press). The benefits of interleaved practice for
learning. In J. C. Horvath, J. Lodge, & J. A. C. Hattie (Eds.),
From the laboratory to the classroom: Translating the learning
sciences for teachers. New York: Routledge.
Kang, S. H. K., Lindsey, R. V., Mozer, M. C., & Pashler, H. (2014).
Retrieval practice over the long term: Should spacing be
expanding or equal-interval? Psychonomic Bulletin & Review,
21, 1544-1550.
Kang, S. H. K., McDaniel, M. A., & Pashler, H. (2011). Effects
of testing on learning of functions. Psychonomic Bulletin &
Review, 18, 998-1005.
Kang, S. H. K., McDermott, K. B., & Roediger, H. L. (2007).
Test format and corrective feedback modify the effect of test-
ing on long-term retention. European Journal of Cognitive
Psychology, 19, 528-558.
Kang, S. H. K., & Pashler, H. (2012). Learning painting styles:
Spacing is advantageous when it promotes discriminative con-
trast. Applied Cognitive Psychology, 26, 97-103.
Kapler, I. V., Weston, T., & Wiseheart, M. (2015). Spacing in a
simulated undergraduate classroom: Long-term benefits for
factual and higher-level learning. Learning and Instruction,
36, 38-45.
Karpicke, J. D., & Grimaldi, P. J. (2012). Retrieval-based learning:
A perspective for enhancing meaningful learning. Educational
Psychology Review, 24, 401-418.
Kornell, N. (2009). Optimising learning using flashcards: Spacing is
more effective than cramming. Applied Cognitive Psychology,
23, 1297-1317.
Kornell, N., & Bjork, R. A. (2008). Learning concepts and cat-
egories: Is spacing the “enemy of induction”? Psychological
Science, 19, 585-592.
Kornell, N., Castel, A. D., Eich, T. S., & Bjork, R. A. (2010).
Spacing as the friend of both memory and induction in young
and older adults. Psychology and Aging, 25, 498-503.
Landauer, T. K., & Bjork, R. A. (1978). Optimum rehearsal patterns
and name learning. In M. M. Gruneberg, P. E. Morris, & R.
N. Sykes (Eds.), Practical aspects of memory (pp. 625-632).
London, England: Academic Press.
Lindsey, R. V., Shroyer, J. D., Pashler, H., & Mozer, M. C. (2014).
Improving students’ long-term knowledge retention through
personalized review. Psychological Science, 25, 639-647.
Lortie, D. C. (1975). Schoolteacher: A sociological study. Chicago,
IL: University of Chicago Press.
Magliero, A. (1983). Pupil dilations following pairs of identical and
related to-be-remembered words. Memory & Cognition, 11,
609-615.
Mayer, R. E. (1977). The sequencing of instruction and the con-
cept of assimilation-to-schema. Instructional Science, 6,
369-388.
Mayer, R. E. (2002). Rote versus meaningful learning. Theory Into
Practice, 41, 226-232.
Metcalfe, J., & Xu, J. (in press). People mind wander more dur-
ing massed than spaced inductive learning. Journal of
Experimental Psychology: Learning, Memory, and Cognition.
Advanced online publication. doi: 10.1037/xlm0000216
Morehead, K., Rhodes, M. G., & DeLozier, S. (2016). Instructor and
student knowledge of study strategies. Memory, 24, 257-271.
Organisation for Economic Co-operation and Development. (2014).
Education at a glance 2014. Paris, France: Author. Retrieved
from doi:10.1787/eag-2014-en
Pearson. (2012). The learning curve: Lessons in country perfor-
mance in education. Retrieved from http://thelearningcurve.
pearson.com/reports/the-learning-curve-report-2012
Rawson, K. A., & Kintsch, W. (2005). Rereading effects depend
on time of test. Journal of Educational Psychology, 97,
70-80.
Rea, C. P., & Modigliani, V. (1985). The effect of expanded ver-
sus massed practice on the retention of multiplication facts and
spelling lists. Human Learning: Journal of Practical Research
& Applications, 4, 11-18.
Rickard, T. C., Lau, J. S. H., & Pashler, H. (2008). Spacing and the
transition from calculation to retrieval. Psychonomic Bulletin
& Review, 15, 656-661.
Roediger, H. L., & Butler, A. C. (2011). The critical role of retrieval
practice in long-term retention. Trends in Cognitive Sciences,
15, 20-27.
Rohrer, D. (2009). The effects of spacing and mixing practice
problems. Journal for Research in Mathematics Education,
40, 4-17.
Kang 19
Rohrer, D. (2012). Interleaving helps students distinguish among
similar concepts. Educational Psychology Review, 24, 355-
367.
Rohrer, D., Dedrick, R. F., & Burgess, K. (2014). The benefit of
interleaved mathematics practice is not limited to superficially
similar kinds of problems. Psychonomic Bulletin & Review, 21,
1323-1330.
Rohrer, D., Dedrick, R. F., & Stershic, S. (2015). Interleaved prac-
tice improves mathematics learning. Journal of Educational
Psychology, 107, 900-908.
Rohrer, D., & Taylor, K. (2006). The effects of overlearning and
distributed practice on the retention of mathematics knowl-
edge. Applied Cognitive Psychology, 20, 1209-1224.
Rohrer, D., & Taylor, K. (2007). The shuffling of mathematics
practice problems improves learning. Instructional Science,
35, 481-498.
Siegler, R. S. (1988). Strategy choice procedures and the devel-
opment of multiplication skill. Journal of Experimental
Psychology: General, 117, 258-275.
Sobel, H. S., Cepeda, N. J., & Kapler, I. V. (2011). Spacing effects
in real-world classroom vocabulary learning. Applied Cognitive
Psychology, 25, 763-767.
Soderstrom, N. C., & Bjork, R. A. (2014). Testing facilitates the
regulation of subsequent study time. Journal of Memory and
Language, 73, 99-115.
Storm, B. C., Bjork, R. A., & Storm, J. C. (2010). Optimizing
retrieval as a learning event: When and why expanding retrieval
practice enhances long-term retention. Memory & Cognition,
38, 244-253.
Susser, J. A., & McCabe, J. (2013). From the lab to the dorm room:
Metacognitive awareness and use of spaced study. Instructional
Science, 41, 345-363.
Taylor, K., & Rohrer, D. (2010). The effects of interleaving prac-
tice. Applied Cognitive Psychology, 24, 837-848.
Toppino, T. C., & Gerbier, E. (2014). About practice: Repetition,
spacing, and abstraction. The Psychology of Learning and
Motivation, 60, 113-189.
Vlach, H. A., & Sandhofer, C. M. (2012). Distributing learning over
time: The spacing effect in children’s acquisition and general-
ization of science concepts. Child Development, 83, 1137-1144.
Wahlheim, C. N., Maddox, G. B., & Jacoby, L. L. (2014). The
role of reminding in the effects of spaced repetitions on cued
recall: Sufficient but not necessary. Journal of Experimental
Psychology: Learning, Memory, and Cognition, 40, 94-105.
