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Sleep right after studying new material is more conducive to memory than a period of wakefulness. Another way to counteract forgetting is to practice retrieval: taking a test strengthens memory more effectively than restudying the material. The current work aims at investigating the interaction between sleep and testing by asking if testing adds to, neutralizes, or decreases the effect of sleep on memory? We tested this in one pilot and one experiment by manipulating the timing of the practice test as well as whether practice was followed by sleep or wakefulness when learning foreign language vocabulary. Taking a delayed practice test significantly reduces forgetting for both the sleep and the wakefulness group. An immediate practice test, in contrast, had no such effect; here we find the standard beneficial sleep effect. However, the immediate practice test leads to higher recall in the final test in comparison to a delayed practice test, but only for the sleep group. Practical recommendations imply two things: first, if students study in the evening, they should test themselves immediately after learning. Second, if students study during the day the practice test should be delayed in order to reinforce memory and reduce forgetting of the material.
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Using day and night -- scheduling retrieval practice and
sleep
Journal:
Psychology Learning and Teaching
Manuscript ID
PLAT-20-0003.R2
Manuscript Type:
Articles
Keywords:
sleep, retrieval practice, forgetting
Abstract:
Sleep right after studying new material is more conducive to memory
than a period of wakefulness. Another way to counteract forgetting is to
practice retrieval: Taking a test strengthens memory more effectively
than restudying the material. The current work aims at investigating the
interaction between sleep and testing by asking if testing adds to,
neutralizes, or decreases the effect of sleep on memory? We tested this
in one pilot and one experiment by manipulating the timing of the
practice test as well as whether practice was followed by sleep or
wakefulness when learning foreign language vocabulary. Taking a
delayed practice test significantly reduces forgetting for both, the sleep
and the wakefulness group. An immediate practice test, on the contrary,
had no such effect; here we find the standard beneficial sleep effect.
However, the immediate practice test leads to higher recall in the final
test in comparison to a delayed practice test, but only for the sleep
group. Practical recommendations imply two things: First, if students
study in the evening, they should test themselves immediate after
learning. Second, if students study during the day the practice test
should be delayed in order to reinforce memory and reduce forgetting of
the material.
https://mc.manuscriptcentral.com/platjournal
Psychology Learning and Teaching
For Peer Review
Abstract
Sleep right after studying new material is more conducive to memory than a period of
wakefulness. Another way to counteract forgetting is to practice retrieval: Taking a test
strengthens memory more effectively than restudying the material. The current work aims at
investigating the interaction between sleep and testing by asking if testing adds to, neutralizes, or
decreases the effect of sleep on memory? We tested this in one pilot and one experiment by
manipulating the timing of the practice test as well as whether practice was followed by sleep or
wakefulness when learning foreign language vocabulary. Taking a delayed practice test
significantly reduces forgetting for both, the sleep and the wakefulness group. An immediate
practice test, on the contrary, had no such effect; here we find the standard beneficial sleep effect.
However, the immediate practice test leads to higher recall in the final test in comparison to a
delayed practice test, but only for the sleep group. Practical recommendations imply two things:
First, if students study in the evening, they should test themselves immediate after learning.
Second, if students study during the day the practice test should be delayed in order to reinforce
memory and reduce forgetting of the material.
Keywords: sleep, retrieval practice, forgetting, memory consolidation
Words Abstract: 200
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Using day and night -- scheduling retrieval practice and sleep
Sleep that follows directly upon the encoding of new information reduces time-dependent
forgetting, as is demonstrated in studies on the beneficial effect of sleep on memory. Jenkins and
Dallenbach (1924), for example, first demonstrated superior memory for nonsense syllables
following an interval containing sleep compared to an equally long interval of wakefulness. The
beneficial effect of sleep on declarative memory has been observed for different study materials
like nonsense syllables (Benson & Feinberg, 1975; Jenkins & Dallenbach, 1924), associative
word pairs (Plihal & Born, 1997), vocabulary (Gais, Lucas, & Born, 2006), or word lists (Ficca,
Lombardo, Rossi, & Salzarulo, 2000). Overall, several studies have shown a beneficial effect of
sleep over a wake period on memory leaving little doubt that sleep is a potent way to reduce
forgetting of newly acquired material (e.g., Barrett & Ekstrand, 1972; Diekelmann, Wilhelm, &
Born, 2009).
The exact mechanisms underlying the benefit of sleep have not been yet fully uncovered, but
different theoretical candidates have been proposed. Earlier theories assumed that sleep is a
passive state, protecting learned material against retroactive interference (Jenkins & Dallenbach,
1924; for a discussion see Ellenbogen, Payne, & Stickgold, 2006). However, newer research
emphasizes active memory consolidation as explanation for the benefit of sleep (for a review, see
Conte & Ficca, 2013). Memory consolidation is a process whereby previously formed labile
memory traces are transformed and integrated into a network of pre-existing long-term
memories. Consolidation during sleep is thought to diminish forgetting of the material leading to
better performance at the delayed test after sleep compared to wakefulness (Diekelmann et al.,
2009).
Another powerful strategy to reduce time-dependent forgetting is retrieval practice.
Retrieving newly acquired information instead of simply restudying it has been shown to be an
successful way to reduce forgetting (also called the testing effect; e.g., Roediger & Karpicke,
2006; Roediger & Butler, 2011) even without feedback in the testing situation (Karpicke &
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Roediger, 2010). Furthermore, the testing effect could be demonstrated in teaching and learning
psychology (Schwieren, Barenberg, & Dutke, 2017) showing that the effect is not restricted to
laboratory studies. The strength of this effect depends on different factors like the difficulty of
the retrieval task (Carpenter & DeLosh, 2006), the retention interval between retrieval practice
and final test (Roediger & Karpicke, 2006), the number of the practice tests (Karpicke &
Roediger, 2010), or the timing of the practice test (Karpicke & Roediger, 2007; Karpicke &
Roediger, 2010). Karpicke and Roediger (2007), for instance, showed that delaying the practice
test was more conducive to long-term retention of the learned material than an immediate
practice test. Testing an item immediately after learning led subjects to recall this item while it
was still in their immediate awareness, which is similar to a massed learning situation (Karpicke
& Roediger, 2007; Karpicke & Roediger, 2010). However, the influence of the timing of the
practice test seems to be more complicated. In contrast to Karpicke and Roediger (2007),
Karpicke and Roediger (2010) reported positive and negative effects of delayed testing. In
Experiment 1, they found that taking an immediate first test improved long-term retention, in
Experiment 2 no such effect could be detected. However, it has to be noted, that the used
materials differed between Karpicke and Roediger (2007) and Karpicke and Roediger (2010).
Whereas Karpicke and Roediger (2007) used vocabulary word pairs, Karpicke and Roediger
(2010) used brief text passages. Furthermore, the delayed cued recall test used by Karpicke and
Roediger (2007) occurred already after five trials after studying a wordpair. The first delayed test
used by Karpicke and Roediger (2010) occurred approximately after 8 minutes.
The current set of experiments examines the interaction between sleep and retrieval practice
more closely. A previous study by Bäuml, Holterman, and Abel (2014) found that sleep that
followed directly upon encoding affected word-material that was retrieved versus restudied
differently: Whereas the wakefulness group benefited from testing by showing better memory
performance for previously retrieved versus restudied items, a reduced or even eliminated testing
effect for the sleep group could be found. Similar to other studies, the sleep and the wakefulness
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group were tested 12 hours after the initial learning phase. Interestingly, the reason for this
reduced testing effect was that sleep benefited recall of restudied items but left recall of retrieved
items unaffected. When comparing memory for items between the sleep and the wakefulness
group, the sleep group showed improved performance for restudied items, but no enhanced
memory for retrieved items. It seems that beneficial effects from retrieval practice reduce the
beneficial effect of sleep. Moreover, these results were replicated using spatial memory by
Antony and Paller (2018). However, a recent study from Abel et al. (2019) showed benefits of
sleep on recall after retrieval practice, but only if it was combined with feedback. How can these
results be explained? As the authors discussed, it may be that retrieving information strengthens
fragile memory traces. Therefore, the beneficial effect of sleep on memory cannot improve recall
any further. When giving feedback, previously non-retrieved items can now be again forgotten in
the time between learning and final test or benefit from the positive effect of sleep on recall.
In contrast to Bäuml et al. (2014), we were not interested in evaluating the differential effect
of restudied versus retrieved items. Since studies have repeatedly shown the superiority of testing
as a learning event (e.g., Roediger & Butler, 2011), we instead aimed at manipulating the timing
of the practice test to determine its optimal placement in a sleep-wake-paradigm. There are
several studies showing that students often prefer massed (= immediate learning of all the
material) instead of spaced learning (e.g., Taraban, Maki, & Rynearson, 1999). Given the number
of accumulating evidence and the general recommendation from learning scientists (Dunlosky,
Rawson, Marsh, Nathan, & Willingham, 2013; Roediger & Pyc, 2012) that students should take
tests to boost their memory, how does this recommendation systematically interact with other
factors that are part of their daily lives such as sleep which has also been shown to reduce
forgetting? Does the timing of a practice test make a difference, and if so, when exactly should it
optimally be taken to reduce forgetting in the sleep-wakefulness paradigm?
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To evaluate this research question, we drew on a design often used in studies addressing
research on sleep-associated memory consolidation to the extent that in one condition
participants’ memory for the material was tested immediately after acquisition (which was
considered as learning trial) and again assessed after a retention interval filled with wakefulness
or sleep 12 hours later. Similar to other studies (Gais et al.,2006; Gais et al., 2007), we were
primarily interested in forgetting between the first test after studying and the final test following
the retention interval. Our experiments added a delayed retrieval practice condition that tested
newly acquired material at a delay of two hours1 after acquisition to evaluate how this affects
forgetting after sleep versus wakefulness.
This has practical implications, students would benefit to know the optimal time for a
practice test during the day and before going to bed, respectively, to improve their study
outcome. Psychology students, for example, have to learn a lot of facts, like the names of brain
structures, neurotransmitters, and hormones, but also a lot of different theories and corresponding
experiments. Knowing the optimal schedule for learning could be an effective and time saving
strategy. Optimal learning schedules cannot only improve memory, they can also improve the
metacognitive monitoring and, therefore, the regulation of study behavior. Students that accessed
course material continuously through the semester showed better metacognitive learning
outcome and a higher accuracy of confidence judgements (Barenberg, Roeder, & Dutke, 2018).
We think that two hypotheses can be tested: First, based on Karpicke and Roediger
(2007) it is possible that delayed testing aids to strengthen fragile memory traces resulting in less
forgetting. This may particularly benefit the wakefulness group and not the sleep group as much
because sleep-induced strengthening already leads to a strengthening of fragile memory traces.
Consequently, we would not expect a difference in forgetting between the wakefulness and sleep
group when delayed testing is in place. On the other hand, the sleep benefit over wakefulness
1 A 2-hour delay was chosen strategically: We aimed for a long enough delay that would not interfere too much with
participants’ going to bed habit in the sleep group.
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would occur in the immediate testing condition because no additional boost for the wakefulness
group occurs here. We call this the wakefulness aid hypothesis.
Second, it may be the case that beside the positive effect of delayed testing on memory, sleep still
has an additional effect on memory. Thus, in this case we would expect a main effect of time of
practice test and sleep versus wakefulness – with less forgetting occurring after sleep than after a
period of wakefulness – but no interaction.
Overview of the experiments
We conducted a pilot experiment in the laboratory and a main experiment on the internet. In
both experiments, we manipulated the timing of the practice test (immediate vs. delayed) as well
as whether practice was followed by an interval including or excluding sleep. During the initial
learning session, participants studied foreign vocabulary and took a practice test without
feedback immediately or two hours later. After a 12-hour retention interval, we assessed memory
performance of the vocabulary and calculated forgetting during the 12-hour interval between
practice and final test performances (see Figure 1 for an overview).
Pilot Experiment
To obtain initial data for our research question and to test if the strategical use of a 2-hour delay
between learning and practice test in the delayed test groups was appropriate we conducted a
pilot experiment in the laboratory.
Method
Participants
Thirty-eight German-speaking Psychology undergraduates at the University of Mannheim
participated in this laboratory experiment. Two participants had to be excluded due to an
experimenter error which had these participants complete both the immediate and the delayed
test. The remaining thirty-six participants (26 female, Mage = 21.61 years, SDage = 2.80 years, age
range = 19 to 36 years) took part in the experiment in exchange to course credits. Participants
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were randomly assigned to four experimental conditions and were fairly evenly distributed across
experimental conditions (Nsleepimmediate = 8; Nsleepdelayed = 10; Nwakeimmediate = 9; Nwakedelayed = 9).
Design
We manipulated the delay of the practice test and sleep versus wakefulness in a 2
(condition: sleep versus wakefulness) x 2 (delay of practice test: immediate versus delayed)
between-subjects design.
Materials and Procedure2
Session 1. Depending on the experimental condition, participants started the experiment
either at 9am (wakefulness group) or at 9pm (sleep group). Participants were tested in groups in a
lab in Mannheim ranging in size from one to ten. All lab sessions were programmed using E-Prime
2.0 software (Psychology Software Tools, Pittsburgh, PA), the online session was programmed
using PHP. They were instructed that the experiment consisted of different parts. In addition,
participants were informed about the timing of the later tests. After signing consent forms, they
started the experiment at the computer. They were asked to study 40 Polish-German vocabulary
pairs (Undorf & Erdfelder, 2013) in order to remember the German word in a later cued recall task.
Participants completed a total of two study cycles: A study cycle contained a randomized
presentation of all 40 vocabulary pairs at a rate of 6 seconds per pair followed by a short 2-min
arithmetic distractor task. During the distractor task, simple math equations with solutions were
presented and participants had 8s to decide if the equation was correctly solved or not. Afterwards,
participants were either given the practice test (immediate practice test condition) or dismissed and
emailed the link to the online version of the practice test two hours later (delayed practice test
condition). The practice test was a cued recall test where the Polish words were presented randomly
2 For all reported studies, data and materials are available via the Open Science Framework (OSF) and can
be accessed at https://osf.io/q7asc/?view_only=d470288b56e9426aad657ce3b41e6d91
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one at a time as cues to remember the German translation. Participants then had to write down the
word they remembered via the keyboard. The test was self-paced and no feedback was provided.
Participants were randomly assigned to the immediate or the delayed practice test groups.
Session 2. Participants came to the laboratory for their final session for the final cued
recall test. Participants were asked to recall the German translation to all 40 Polish words. Again,
the Polish words were presented randomly, one at a time on the screen and participants had to
write down their answers via the keyboard. The test was self-paced and no feedback was
provided. In the present experiment, the final test session always took place at either 9am in the
sleep condition and at 9pm in the wakefulness condition. Therefore, the retention interval
(measured from the end of the practice test) was effectively 10 hours in the delayed practice test
condition and 12 hours in the immediate practice test condition. This was done for the sake of
simplicity of running the study in the laboratory. We are aware that this may be a potential
confounding factor. However, after consulting our data we find no indication of a confounding
effect since participants in the delayed practice test condition did not generally outperform
participants in the immediate practice test condition. Thus, the difference in retention interval did
not affect our results.
Analysis strategy
To give an optimal overview of our data, we report recall rates as measure of memory and
memory change as measure of forgetting. Interestingly, there is an ongoing debate how to
measure forgetting (see Loftus, 1992; MacDonald, Stigsdotter-Neely, Derwinger, & Bäckman,
2006). Gais et al. (2006) measured recall and forgetting to test if sleep affects performance
differently than a period of wakefulness. Recall was measured as the number of correctly
remembered words, forgetting was measured as the average individual percent change in recall
performance across the retention interval. For Gais et al. (2006), forgetting was “indicated as
average individual percent change in recall score across periods of sleep and wakefulness” (p.
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261). According to MacDonald et al. (2006), forgetting represents a decline in performance
across different testing times. It is not possible to measure forgetting in a direct way, it can only
be examined by analyzing performance changes over time. The authors also point out that
forgetting always meant an absolute decrement in performance. Therefore, it is “independent of
initial performance level” (p. 369). Moreover, because of this independence, different baseline
performances between groups should not influence forgetting curves and are not of interest for
the forgetting research (MacDonald et al., 2006).
Results
The significance level was set to α = .05 for all statistical tests.
Participants in the sleep condition reported to have slept regularly during the night (M =
7.22 hours; SD = .86), whereas those in the wakefulness condition reported not to have taken
naps during the day. None of the participants reported alcohol intake between sessions.
Forgetting between practice test and final test
A 2 (Test: practice test vs. final test) × 2 (condition: sleep vs. wakefulness) × 2 (delay
of practice test: immediate vs. delayed) repeated measurement ANOVA revealed no main effect
of test, F(1, 32) = 0.003, p = .95,
p2 < .01, no significant main effect of condition, F(1, 32) =
3.65, p = .07,
p2 = .10, nor a significant interaction between test and condition, F(1, 32) = 0.99,
p = .33,
p2 = .03, or between test and delay of practice test, F(1, 32) = 1.24, p = .27,
p2 = .04 or
between condition and delay of practice test, F(1, 32) = 0.99, p = .33,
p2 = .03. However, there
was a significant main effect of delay of practice test, F(1, 32) = 7.73, p = .009,
p2 = .19,
showing better memory in the immediate than in the delayed practice test. Furthermore, there
was a significant three-way interaction between test, condition and delay of practice test, F(1, 32)
= 4.71, p = .038,
p2 = .13 indicating that memory in the two conditions (sleep vs. wakefulness)
was differently affected by immediate and delayed testing. Specifically, in the immediate practice
test condition the standard positive sleep effect occurred: Participants who slept between the end
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of practice and the final test showed less forgetting than participants who were awake during that
time period. In contrast, in the delayed practice test condition the sleep effect was eliminated: It
seems to be that participants in both the sleep and wakefulness condition showed similar
forgetting between practice and final test session.3 Figure 2 (upper panel) shows the mean recall
rates for all four groups.
To assess forgetting between the practice test and the final test, we also calculated
memory changes by subtracting the performance on the practice test (= number of correct
German translations of the Polish vocabulary) from the performance on the final test. Figure 3
shows the memory change for all 4 groups. We report the Bayes Factors (BFs) to weigh the null
and alternative hypotheses against each other. The BF indicates the likelihood with which the
data are obtained under one hypothesis as compared to the other hypothesis. According to
Jeffreys (1961, Appendix B), Raftery (1995) and Wetzels et al. (2011), a BF between 1 and 3 can
be interpreted as weak evidence, a BF between 3 and 20 as positive or substantial evidence, a BF
between 20 and 150 as strong or very strong evidence, and a BF larger than 150 as very strong or
decisive evidence for one of the hypotheses. Because the BF can be used to measure the
likelihood of the H1 as well as the likelihood of the H0. An index denotes which hypothesis is
tested (BF01 for the null hypothesis; BF10 for the alternative hypothesis). All reported BFs were
conducted using JASP (JASP Team, 2018; Marsman & Wagenmakers, 2017). We used the
default prior options for the effects. The BF10 for the main effect of condition (sleep vs.
3 We also ran an analysis of covariance as an alternative statistical procedure to analyse difference scores
and replicated the reported results pattern. A 2 (condition: sleep vs. wakefulness) × 2 (delay of practice
test: immediate vs. delayed) ANCOVA with practice test performance as covariate and final test
performance as dependent variable revealed an expected significant effect of the covariate, F(1, 31) =
245.23, p < 001,
p2 = .89, meaning that performance in the practice test influences final test
performance. When the effect of performance in the practice test is removed, neither a main effect of
condition, F(1, 31) = 3.23, p = .08,
p2 = .09, nor the main effect of delay of practice test, F(1, 31) = 0.01,
p = .92,
p2 < .001, could be found. However, there was a significant interaction between condition and
delay of practice test, F(1, 31) = 6.08, p = .02,
p2 = .12, indicating that memory in the final test was
differently affected by condition (sleep vs. wakefulness) and delay of practice test (immediate vs.
delayed): The difference in recall rates between participants in the sleep conditions and in the wakefulness
conditions were smaller in the delayed testing condition compared to the immediate testing condition.
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wakefulness) was 0.49. However, the BF01 for the null hypothesis was also only 2.04. Similar,
for the main effect of delay of practice test (immediate vs. delayed) the BF10 was 0.56, the BF01
was 1.79. For the interaction between condition and delay of practice test the BFs were BF10=
0.84 for the alternative hypothesis and BF01=1.19 for the null hypothesis. Overall, the BFs were
inconclusive.
Discussion
We found less forgetting after a period of wakefulness for the delayed testing group in
comparison to the immediate testing group. The benefit of sleep was revealed only in the
immediate practice test condition. The elimination of the sleep-related memory benefit was
mainly driven by a decrease in forgetting in the wakefulness group. In terms of forgetting, the
sleep group was not affected by the delay of the practice test. Forgetting was similar irrespective
to the time of the practice test. In line with this, we found a comparable pattern of forgetting over
time for the sleep and the wakefulness condition in the delayed testing condition but not in the
immediate testing condition (Figure 2, upper panel). However, the Bayes Factors showed
inconclusive results: there was neither a clear indication for the alternative hypothesis nor for the
null hypothesis. However, the pilot study used only 36 participants. This could be the reason for
this inconclusive results.
Overall, the findings from our pilot experiment are more in line with the proposed
wakefulness aid hypothesis. Delayed testing presumably aided to strengthen memory traces in
the wakefulness group whereas sleep in itself had a sufficiently beneficial effect on memory
stabilization and protection leading to less forgetting. Immediate testing reveals the typical
benefit of sleep in comparison to wakefulness. However, we also had a few limitations in the
pilot that we address in turn. First, as the Bayes Factors indicated, maybe, we had not enough
participants to come to a clear decision between alternative and null hypothesis. Second, the final
test session was 12 hours after learning for the immediate testing group, but only 10 hours for the
delayed testing group. Third, participants took the practice test either in the laboratory
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(immediate testing) or on the internet (delayed condition). It is possible, that the change of
context in the delayed testing group led a disruption in processing leading to an overall decrease
in performance compared to the immediate testing group. Fourth, we did not control if the
delayed testing groups did the online test exactly 2 hours after the first learning session. Fifth,
some of the Polish-German words were similar to each other and therefore easier to learn.
Experiment
The main experiment was run to test the replicability of the new finding using a larger
and more heterogeneous sample of participants while remedying the abovementioned points. The
experiment differed from the pilot in three major aspects: (i) we used Lithuanian-English
vocabulary (Grimaldi & Rawson, 2010) instead of Polish-German vocabulary, (ii) the experiment
was run on the internet and participants were English native speakers, and (iii) the delay between
practice test and final test was the same in all conditions and fixed at a length of 12 hours.
Method
Participants
Sixty-three English-speaking people participated in this web-based experiment. All
participants were recruited from the online platform Amazon Mechanical Turk. To obtain high
quality data, we restricted study access to people who had at least completed 500 studies on
Amazon Mechanical Turk before and who had an approval rate of at least 95% (see Finley,
20154). The study was accessible to participants on Amazon Mechanical Turk located in the
United States or Canada. Of all participants, six had to be excluded because they either reported
to be familiar with the Lithuanian language or to have cheated on the memory tests (e.g., writing
down vocabulary pairs during initial presentation and using their notes during the test). A final
sample of 57 (39 female) participants remained and was included in the analyses (Nsleepimmediate =
14; Nsleepdelayed = 16; Nwakeimmediate = 15; Nwakedelayed = 12). Their age ranged from 22 to 40 years (M
4 http://www.psychonomic.org/featured-content-detail/high-quality-mturk-data
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= 32.30; SD = 5.05). Participants received a total of $1.50 for their participation in the
experiment.
Materials
Materials comprised 40 Lithuanian – English word translations of similar difficulty taken
from Grimaldi and Rawson (2010). All translations were unfamiliar to the participants.
Participants were asked to study the English translation of each Lithuanian word.
Design
The experiment included a 2×2 between-subject design with the factors delay of practice
test (immediate vs. delayed) and condition (12-h wake versus 12-h sleep). The final test session
followed 12 hours after the practice test regardless of whether it was immediate or delayed.
Although we did not find any effect of slightly different retention intervals in the pilot, we felt
that it would be experimentally cleaner to hold the retention interval constant across conditions.
In addition, the links leading to the study were only active for a short time, therefore, it was not
possible to conduct either the learning or the testing sessions later or earlier. Moreover, this time,
the entire experiment was conducted online. Therefore, all sessions were comparable in regard to
context between the groups.
Procedure
The procedure of the present experiment was the same as the one of the pilot. The only
major difference was that participants used their own computer devices to access and run the
experiment through their web browsers. To make sure that participants logged on to the experiment
at the correct times, automated reminder emails were sent to them at the respective times. The
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experiment was programmed in HTML, PHP, and Javascript and participants could only access
the study at their predetermined times and for a short time frame only5.
Results
The significance level was set to α = .05 for all statistical tests. Again, we report recall
rates as measure of memory and memory change as measure of forgetting. Participants in the
sleep condition reported to have slept regularly during the night (M = 6.9 hours; SD = 1.34)
whereas participants in the wakefulness condition reported not to have taken naps during the day.
Forgetting between practice test and final test
A 2 (Test: practice test vs. final test) × 2 (condition: sleep vs. wakefulness) × 2 (delay
of practice test: immediate vs. delayed) repeated measurement ANOVA revealed no main effect
of test, F(1, 53) = 1.80, p = .19,
p2 = .03, no significant effect of condition, F(1, 53) = 0.63, p =
.43,
p2 = .01, and no significant effect of delay of practice test, F(1, 53) = 0.29, p = .60
p2 =
.01. There was a significant interaction between test and condition, F(1, 53) = 5.95, p = .02,
p2 =
.10, and between test and delay of practice test, F(1, 53) = 6.15, p = .02,
p2 = .10, but not
between condition and delay of practice test, F(1, 53) = 6.15, p = .02,
p2 = .10. Again, there was
a significant three-way interaction between test, condition and delay of practice test, F(1, 53) =
0.19, p = .67
p2 = .003.6 Figure 2 (lower panel) shows the mean recall rates for all four groups.
5 Thanks to Christian Eckert for programming the web-based experiment platform that allowed for reliable internet
data collection.
6Similar to the pilot, we also used an ANCOVA as alternative approach to analyze the difference scores.
A 2 (condition: sleep vs. wakefulness) × 2 (delay of practice test: immediate vs. delayed) ANCOVA with
practice test performance as covariate and final test performance as dependent variable revealed a
significant effect of the covariate, F(1, 52) = 440.73, p < 001,
p2 = .89. Again, performance in the
practice test influenced performance on the final test. When the effect of practice test performance was
removed, a main effect of condition F(1, 52) = 6.24, p = .02,
p2 = .11, and a main effect of delay of
practice test, F(1, 52) = 5.40, p = .02,
p2 = .09, were found. In addition, the interaction between condition
and delay of practice test was significant, F(1, 52) = 9.02, p = .004,
p2 = .15. The difference in recall rates
between participants in the sleep condition and in the wakefulness condition were smaller in the delayed
testing condition compared to the immediate testing condition.
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Also similar to the pilot, we calculated the BFs for the memory change to corroborate
our results. Figure 4 shows the memory change for all 4 groups (Msleep;immediate = .71, Msleep;delayed
=.25 , Mwake;immediate = -4.07, Mwake;delayed = 0.75). The BF10 for the main effect of condition (sleep
vs. wakefulness ) was 14.12 (BF01 = 0.07) showing that the alternative hypothesis was 14 times
more likely than the null hypothesis indicating that, in comparison to wakefulness, sleeping was
more beneficial for memory. The BF10 for the main effect of delay of practice test (immediate vs.
delayed) was 10.78 (BF01 = 0.09) indicating strong evidence for the alternative hypothesis and
showing that immediate testing led to more forgetting in the final test. Moreover, the BF10 for the
interaction between condition and delay of practice test was 18.99 (BF01=0.05) also speaking for
strong evidence. It seems to be that the standard sleep effect occurred in the immediate practice
test condition only, i.e., less forgetting in the sleep condition than in the wakefulness condition.
Discussion
Our experiment replicates and extends the results of the pilot to a more heterogeneous
population, to word material of a different language, and to a different experimental setting.
Forgetting over time for the sleep and the wakefulness condition show a similar pattern in
the delayed testing condition but differ in the immediate testing condition (with more forgetting
in the wakefulness group, Figure 2, lower panel). The successful replication and extension of our
finding fosters the proposed wakefulness aid hypothesis.
General Discussion
In our experiments, we tested the effect of delaying a practice test on forgetting of foreign
vocabulary during a sleep- or wakefulness-filled interval of up to 12 hours. We find the standard
beneficial sleep effect when participants were immediately tested on the material at the end of the
practice session. Hence, a succeeding period of sleep led to less forgetting than a succeeding
period of wakefulness. This replicates former findings by Gais et al. (2006; 2007). However,
when the practice test was delayed by two hours, forgetting was comparably low in both the
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sleep and wakefulness condition. A delayed practice test decreased forgetting in the wakefulness
condition while leaving forgetting in the sleep group unaffected. Overall, during the practice test,
the immediate test groups showed better performance than the delayed testing groups. However,
forgetting in the immediate wakefulness group led to the recall of fewer vocabulary compared to
the delayed wakefulness group on the final test. For the sleep group, the difference between the
immediate and the delayed testing condition persisted.
We were able to replicate the findings from the pilot study using a different experimental
setting, another population of participants, and different vocabulary materials. Based on this, we
think that these new findings are of theoretical as well as practical relevance. As discussed above,
Bäuml et al. (2014) found that the beneficial effects from testing reduce the beneficial effect of
sleep. The authors discussed that retrieving information strengthens items to a much higher
degree than restudying (an argumentation in line with the bifurcation model that assumes that
testing strengthens successfully retrieved items to a high degree while leaving non-retrieved
items unaffected, Halamish & Bjork, 2011). Because of this, additional sleep-induced
strengthening of the items may not improve recall further. In contrast, Abel et al. (2019) could
find benefits of sleep on recall after retrieval practice, but only if it was combined with feedback.
However, this does not contradict the theoretical explanation from Bäuml et al. (2014). Initially
non-retrieved items can be lifted above recall threshold after corrective feedback (Pastötter &
Bäuml, 2016). Now, time between learning and final test can lead to two things: These items can
again fall below recall threshold (time-dependent forgetting) or these items can benefit from
sleep-associated strengthening creating a positive effect of sleep on memory. Therefore, sleep no
longer modulates the testing effect (Abel et al, 2019).
A similar argumentation can also explain our results: A delayed practice test considerably
strengthened fragile memory traces (Karpicke & Roediger, 2007) pushing them above recall
threshold which becomes particularly important when a longer period of wakefulness follows.
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Items retrieved during the delayed practice test seem to be strengthened to a higher degree than
items retrieved immediate after learning and remain over the recall threshold. Sleep, presumably
through active consolidation processes (see Diekelmann & Born, 2010; Marshall & Born, 2007;
Stickgold & Walker, 2013), is per se sufficient to ensure little forgetting of newly acquired
foreign vocabulary. Consequently, delaying the practice test had a differential effect on forgetting
in the sleep versus wakefulness condition: It did neither increase or decrease sleep-related
forgetting, but rather helped maintaining recently studied material through a period of
wakefulness. For the immediate practice test condition, the typical benefit of sleep over
wakefulness was found. Sleeping after the test helped to maintain this material for the final test.
For the wake group, however, the items retrieved during the immediate practice test were still
subject to decay over time. Participants were not able to maintain the learned material in their
memory (a finding in line with Karpicke & Roediger, 2007, Exp. 3).
A caveat with regard to the present findings may be that we did not control the timing of
sleep onset. There are different possibilities how this could have affected our results: 1)
Participants in the immediate practice condition could have gone to bed soon after encoding, and,
therefore, slept longer than participants in the delayed condition or 2) for the delayed practice
condition, sleep onset occurred sooner after the practice test. For both experiments, we asked our
participants at approximately what time did they fall asleep the night before during the final test
session. For the pilot, the mean reported time was around 12.13 am for the delayed and around
11.44 pm for the immediate group. For the main experiment, the mean reported time was around
11.56 pm for the delayed and around 11.10 pm for the immediate group. Based on these data,
scenario 1 seems to be unlikely. However, it was indeed the case that there was less time
between practice test and sleep in the delayed than in the immediate sleep condition.
Nevertheless, there was no benefit of sleep, our main finding was that the wakefulness group
showed less forgetting in the delayed condition than in the immediate condition.
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Many studies showed that retrieval practice and intervals between study and test that are
filled with sleep are both beneficial for memory. However, there is also the question how long
lasting these effects are. For the testing effect, less forgetting was found after 2 days (Thompson,
Wenger, & Bartling, 1978; Wenger, Thompson, & Bartling, 1980) or after 7 days (Roediger &
Karpicke, 2006; Wheeler, Ewers, & Buonanno, 2003), and even after 42 days (Carpenter,
Pashler, Wixted, & Vul, 2008). The persistent effect of sleep on memory seems to be more
complicated. There are studies reporting positive effects of sleep even after delays larger than
12h (see, for example, Gais et al., 2006; Griessenberger et al., 2012; Stickgold, James, &
Hobson; 2000). Abel et al. (2019) were not able to find a sleep benefit after 24h or 7 days. There
is the possibility that sleep has an active as well as a passive contribution on memory and that
this may vary with experimental task (Abel et al., 2019). However, our study cannot make any
conclusions about the persistence of our findings after a longer period of time. This should be
investigated in more detail in future work.
Interestingly, in several experiments, Abel et al. (2019), Bäuml et al. (2014), and
Antony & Paller (2018) found no sleep benefits on memory after immediate tests without
corrective feedback. In contrast, in the study presented here, we observed a benefit of sleep for
such an immediate test. However, in all of the experiments discussed above, participants had
only one initial study cycle before they started a varying number of practices tests. In our study,
they had two study cycles before engaging in one practice test. It is possible that this additional
study cycle improved recall for both, the sleep and the wake group. However, when recall is
improved there is also a greater risk to forget. We think that it is possible that by increasing recall
with two study cycles, we also gave room for the wake group to forget more than the sleep
group. As discussed above, sleep in itself aids to strengthen fragile memory traces resulting in
less forgetting.
At the beginning of our article, we asked the question if the timing of a practice test
makes a difference, and if so, when exactly should it optimally be taken? The new and important
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finding of this study is that wakefulness after encoding does not always lead to more forgetting.
When delaying retrieval practice, it is possible to remember as much on the final test as on the
practice test. Given that it is not always possible to learn right before sleeping, our study shows
that it is possible to compensate the beneficial effect of sleep on memory and has therefore
meaningful relevance for the learning schedule of students. Based on this, practical
recommendations for students in educational settings could be the following: If students study,
for example, the names of brain structures in the evening, they should test themselves before
going to bed – this practice test should follow immediate after learning. However, if students
decide to study during the day and anticipate a longer wakefulness stretch the practice test should
be delayed in order to reinforce memory and reduce forgetting of the material.
Interestingly, when teaching psychology students about learning and memory, they often
rely on inappropriate strategies to learn this information for later tests. Many college students
have low metacognitive awareness about which learning strategy is really beneficial for memory
(McCabe, 2011). Unfortunately, the strategies known as very effective for long-term learning,
like spacing (Rohrer & Pashler, 2007) or testing (Roediger & Karpicke, 2006), often make this
learning very slow (so-called desirable difficulties, Bjork, 1994) and are therefore avoided even
by psychology students. To increase the awareness of the beneficial effects of these strategies on
memory, classroom demonstrations should be used (McCabe, 2014). Our study could be used as
a classroom demonstration after the discussion of the beneficial effects of spacing, testing and
sleep on long-term memory. To increase motivation of the students, it would also be possible to
use material relevant for them (e.g., names of hormones, brain structures etc.) and test the
influence of this material on the effects found in our studies.
Such a classroom demonstration could also be used to increase the empirical basis for
evaluating our effect including its generalizability (Balch, 2006). Further research still has to
investigate the robustness of our findings as well as the optimal delay between studying and first
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practice test to obtain the best results as well as the generalizability to more complex material
and the influence of motivation.
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REFFERENCES
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Figure Captions
Figure 1. Schematic presentation of all conditions in the pilot and the main experiment: In the 12-
h wake condition (group I and II), the learning of the material took place at 9 am. In the 12-h
sleep condition (group III and IV), the learning of the material took place at 9 pm. For the
immediate testing groups the practice test followed immediately after the two learning rounds; in
the delayed testing groups the practice test started at 11 am or pm (depending on sleep or
wakefulness condition). (LL) two learning cycles, (PT) practice test, (FT) final test.
Figure 2. Forgetting over time (based on the total number of correct recalled items) between
practice test and final test (immediate testing: immediately after the learning phase; delayed
testing: 2 hours after the learning phase) for cued recall of the English word in the pilot (upper
panel) main Experiment (lower panel). Error bars represent standard errors of the means.
Figure 3. Memory change (based on the total number of recalled items) between practice test
(immediate group: immediately after the learning phase; delayed group: 2 hours after the learning
phase) and final test (test session) for cued recall of the German word (given the Polish word as
cue) in the pilot. Error bars represent standard errors of the means.
Figure 4. Memory change (based on the total number of correct recalled items) between practice
test (immediate group: immediately after the learning phase; delayed group: 2 hours after the
learning phase) and final test (test session) for cued recall of the English word (given the
Lithuanian word as cue) in the main Experiment. Error bars represent standard errors of the
means.
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Figures
Figure 1
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Figure 2
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... Others in this Special Issue examined the optimal timing of the retrieval-practice task. For optimal learning, should a retrieval-practice activity be administered immediately after learning or two hours later (Kroneisen & Kuepper-Tetzel, 2021)? Can a retrieval task enhance learning if it is administered as a pre-test (i.e., before all of the relevant content has been taught; Giebl et al., 2021)? ...
... Despite increased experimental control, lab-based studies can still closely reflect the type of learning that students do in genuine classes. Indeed, studies in this Special Issue have taken such an approach, conducting lab-based experiments of the testing effect with educationally relevant materials such as foreign-language transitions (Bertilsson et al., 2021;Kroneisen & Kuepper-Tetzel, 2021) and computer programming (Giebl et al., 2021; see Table 1). Bertilsson and colleagues examined individual differences in cognitive and personality traits, specifically working memory capacity, grit (i.e., perseverance and passion for longterm goals), and need for cognition (the tendency for an individual to engage in and enjoy thinking), which have all been shown to relate to academic achievement (e.g., Cowan, 2014;Duckworth & Quinn, 2009;Sadowski & Gulgoz, 1992). ...
... Create opportunities for retrieval practice, even if your students will have difficulties at times. Kroneisen & Kuepper-Tetzel, 2021 If you do not have time to sleep after learning, delay retrieval practice after initial learning to enhance long-term memory. ...
Article
Full-text available
Students and instructors are looking for effective study and instructional strategies that enhance student achievement across a range of content and conditions. The current Special Issue features seven articles and one report, which used varied methodologies to investigate the benefits of practising retrieval and providing feedback for learning. This editorial serves as an introduction and conceptual framework for these papers. Consistent with trends in the broader literature, the research in this Special Issue goes beyond asking whether retrieval practice and feedback enhance learning, but rather, when, for whom, and under what conditions. The first set of articles examined the benefits of retrieval practice compared to restudy (i.e., the testing effect) and various moderators of the testing effect, including participants’ cognitive and personality characteristics ( Bertilsson et al., 2021 ) as well as the timing of the practice test and sleep ( Kroneisen & Kuepper-Tetzel, 2021 ). The second set of articles examined the efficacy of different types of feedback, including complex versus simple feedback ( Enders et al., 2021 ; Pieper et al., 2021 ) and positively or negatively valenced feedback ( Jones et al., 2021 ). Finally, the third set of articles to this Special Issue examined practical considerations of implementing both retrieval practice and feedback with educationally relevant materials and contexts. Some of the practical issues examined included when students should search the web to look for answers to practice problems ( Giebl et al., 2021 ), whether review quizzes should be required and contribute to students’ final grades ( den Boer et al., 2021 ), and how digital learning environments should be designed to teach students to use effective study strategies such as retrieval practice ( Endres et al., 2021 ). In short, retrieval and feedback practices are effective and robust tools to enhance learning and teaching, and the papers in the current Special Issue provide insight into ways for students and teachers to implement these strategies.
... An overreliance on small sample sizes in many experiments is likely a major contributor to conflicting results (2), with studies being underpowered to detect true effects. While it is challenging to recruit large samples for typical laboratory experiments, utilizing online tools to examine the behavioral effect of sleep on memory represents a promising avenue to increase sample size and sample from a broader portion of society (17)(18)(19). We turned to this resource to examine, in two well-powered experiments, whether sleep enhances emotional memory in human adults in the largest studies of sleep and emotional memory to date. ...
Article
Full-text available
Research suggests that sleep benefits memory. Moreover, it is often claimed that sleep selectively benefits memory for emotionally salient information over neutral information. However, not all scientists are convinced by this relationship [e.g., J. M. Siegel. Curr. Sleep Med. Rep. , 7, 15–18 (2021)]. One criticism of the overall sleep and memory literature—like other literature—is that many studies are underpowered and lacking in generalizability [M. J. Cordi, B. Rasch. Curr. Opin. Neurobiol. , 67, 1–7 (2021)], thus leaving the evidence mixed and confusing to interpret. Because large replication studies are sorely needed, we recruited over 250 participants spanning various age ranges and backgrounds in an effort to confirm sleep’s preferential emotional memory consolidation benefit using a well-established task. We found that sleep selectively benefits memory for negative emotional objects at the expense of their paired neutral backgrounds, confirming our prior work and clearly demonstrating a role for sleep in emotional memory formation. In a second experiment also using a large sample, we examined whether this effect generalized to positive emotional memory. We found that while participants demonstrated better memory for positive objects compared to their neutral backgrounds, sleep did not modulate this effect. This research provides strong support for a sleep-specific benefit on memory consolidation for specifically negative information and more broadly affirms the benefit of sleep for cognition.
... Finally, as in most studies measuring consolidation, it should be noted that offline improvement can be a result of the effect of testing, rather than a truly offline process (Eriksson et al., 2011;Schoch et al., 2017). Studies aiming to ameliorate this problem by including separate groups tested in different intervals show the benefit of active consolidation in addition to the facilitative effect of testing itself (Kroneisen & Kuepper-Tetzel, 2021). ...
Article
Full-text available
The current study explores the effects of time and sleep on the consolidation of a novel language learning task containing both item-specific knowledge and the extraction of grammatical regularities. We also compare consolidation effects in language and motor sequence learning tasks, to ask whether consolidation mechanisms are domain general. Young adults learned to apply plural inflections to novel words based on morpho-phonological rules embedded in the input and learned to type a motor sequence using a keyboard. Participants were randomly assigned into one of two groups, practicing each task during the morning or evening hours. Both groups were retested 12 and 24 hrs. post training. Performance on frequent trained items in the language task stabilized only following sleep, consistent with a hippocampal mechanism for item-specific learning. However, regularity extraction, indicated by generalization to untrained items in the linguistic task, as well as performance on motor sequence learning, improved 24 hours post training, irrespective of the timing of sleep. This consolidation process is consistent with a fronto-striatal skill learning mechanism, common across the language and motor domains. This conclusion is further reinforced by cross domain correlations at the individual level between improvement across 24 hours in the motor task and in the low-frequency trained items in the linguistic task, which involve regularity extraction. Taken together, our results at the group and individual levels suggest that some aspects of consolidation are shared across the motor and language domains, and more specifically between motor sequence learning and grammar learning.
... However, given the important differences in experimental control between our online study and the original laboratory experiment of Wilhelm et al. [24], further work is necessary to determine the conditions under which these selective sleep-memory effects may emerge. Nevertheless, our findings add to a developing body of online research indicating that sleep provides robust and long-lasting benefits for memory [56]. ...
Article
Full-text available
Overnight consolidation processes are thought to operate in a selective manner, such that important (i.e. future-relevant) memories are strengthened ahead of irrelevant information. Using an online protocol, we sought to replicate the seminal finding that the memory benefits of sleep are enhanced when people expect a future test [Wilhelm et al., 2011]. Participants memorised verbal paired associates to a criterion of 60 percent (Experiment 1) or 40 percent correct (Experiment 2) before a 12-hour delay containing overnight sleep (sleep group) or daytime wakefulness (wake group). Critically, half of the participants were informed that they would be tested again the following day, whereas the other half were told that they would carry out a different set of tasks. We observed a robust memory benefit of overnight consolidation, with the sleep group outperforming the wake group in both experiments. However, knowledge of an upcoming test had no impact on sleep-associated consolidation in either experiment, suggesting that overnight memory processes were not enhanced for future-relevant information. These findings, together with other failed replication attempts, show that sleep does not provide selective support to memories that are deemed relevant for the future.
Article
There is increasing evidence to indicate that sleep plays a role in language acquisition and consolidation; however, there has been substantial variability in methodological approaches used to examine this phenomenon. This systematic review and meta-analysis aimed to investigate the effect of sleep on novel word learning in adults, and explore whether these effects differed by retrieval domain (i.e., recall, recognition, and tests of lexical integration). Twenty-five unique studies met the inclusion criteria for the review, and 42 separate outcome measures were synthesized in the meta-analysis (k = 29 separate between-group comparisons, n = 1,396 participants). The results from the omnibus meta-analysis indicated that sleep was beneficial for novel word learning compared with wakefulness (g = 0.50). Effect sizes differed across the separate domain-specific meta-analyses, with moderate effects for recall (g = 0.57) and recognition memory (g = 0.52), and a small effect for tasks which measured lexical integration (g = 0.39). Overall, the results of this meta-analysis indicate that sleep generally benefits novel word acquisition and consolidation compared with wakefulness across differing retrieval domains. This systematic review highlights the potential for sleep to be used to improve second-language learning in healthy adults, and overall provides further insight into methods to facilitate language development.
Article
Full-text available
We illustrate the Bayesian approach to data analysis using the newly developed statistical software program JASP. With JASP, researchers are able to take advantage of the benefits that the Bayesian framework has to offer in terms of parameter estimation and hypothesis testing. The Bayesian advantages are discussed using real data on the relation between Quality of Life and Executive Functioning in children with Autism Spectrum Disorder.
Chapter
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examine 2 . . . contributors to nonoptimal training: (1) the learner's own misreading of his or her progress and current state of knowledge during training, and (2) nonoptimal relationships between the conditions of training and the conditions that can be expected to prevail in the posttraining real-world environment / [explore memory and metamemory considerations in training] (PsycINFO Database Record (c) 2012 APA, all rights reserved)
Article
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Description: This 38-page document contains an introduction to the resource, background information on 8 learning and memory strategies, a summary of research on undergraduate student metacognition with regard to these strategies, and from one to four classroom demonstrations per strategy. These demonstrations allow students to experience the effectiveness of the strategies. References are included at the end of the document. Note: 2013 OTRP Instructional Resource Award
Article
Repeatedly studying information is a good way to strengthen memory storage. Nevertheless, testing recall often produces superior long-term retention. Demonstrations of this testing effect, typically with verbal stimuli, have shown that repeated retrieval through testing reduces forgetting. Sleep also benefits memory storage, perhaps through repeated retrieval as well. That is, memories may generally be subject to forgetting that can be counteracted when memories become reactivated, and there are several types of reactivation: (i) via intentional restudying, (ii) via testing, (iii) without provocation during wake, or (iv) during sleep. We thus measured forgetting for spatial material subjected to repeated study or repeated testing followed by retention intervals with sleep versus wake. Four groups of subjects learned a set of visual object-location associations and either restudied the associations or recalled locations given the objects as cues. We found the advantage for restudied over retested information was greater in the PM than AM group. Additional groups tested at 5-min and 1-wk retention intervals confirmed previous findings of greater relative benefits for restudying in the short-term and for retesting in the long-term. Results overall support the conclusion that repeated reactivation through testing or sleeping stabilizes information against forgetting.
Article
Retrieval practice relative to restudy of learned material typically attenuates time-dependent forgetting. A recent study examining this testing effect across 12-h delays filled with nocturnal sleep versus daytime wakefulness, however, showed that sleep directly following encoding benefited recall of restudied but not of retrieval practiced items, which reduced, and even eliminated, the testing effect after sleep (Bäuml, Holterman, & Abel, 2014). The present study investigated in 4 experiments, whether this modulating role of sleep for the testing effect is influenced by two factors that have previously been shown to increase the testing effect: corrective feedback and prolonged retention intervals. Experiments 1a and 1b applied 12-h delays and showed benefits of sleep for recall after both restudy and retrieval practice with feedback, but not after retrieval practice without feedback. Experiments 2a and 2b applied 24-h or 7-day delays and failed to observe any long-lasting benefits of sleep directly after encoding, on both restudied and retrieval practiced items. These results indicate that both corrective feedback and prolonged retention intervals reduce the modulating role of sleep for the testing effect as it can be observed after 12-h delays and in the absence of corrective feedback, which suggests a fairly limited influence of sleep on the effect.
Article
Studies demonstrate that students’ study behavior is frequently dysfunctional, because they tend to cram shortly before examinations. This behavior is antithetical to spaced learning and can impair academic achievement. We investigated the extent that the temporal distribution of learning activities (a) varies as a function of the organization of the course, (b) is subject to individual differences and (c) affects the metacognitive learning outcome. Participants of four lecture-like educational psychology courses (N = 259) were presented with learning materials stored on the university’s online learning platform. New materials were published weekly and access to these materials was automatically registered. The students completed either a test at the end of the semester (in two end-term-test courses) or fulfilled written assignments throughout the semester (in two multiple-assignment courses). Students in the multiple-assignment courses accessed the materials more continuously than students in the end-of-term-test courses. Cluster analyses in the end-of-term-test courses revealed students primarily accessing the materials late in the semester and students accessing the materials continuously throughout the semester. Continuous access was associated with more accurate metacognitive monitoring. The results are discussed in the context of the relation between metacognitive monitoring and the regulation of study behavior.
Article
The testing effect is a robust empirical finding in the research on learning and instruction, demonstrating that taking tests during the learning phase facilitates later retrieval from long-term memory. Early evidence came mainly from laboratory studies, though in recent years applied educational researchers have become increasingly interested in the effects of retrieval practice. We investigated the extent that the testing effect can also be observed and effectively used in psychology classes. Inspection of the research literature yielded 19 publications that tested the effect in the context of learning and teaching psychology. A total of 72 effect sizes were extracted from these publications and subjected to a meta-analysis. A significant overall effect size of d = 0.56 demonstrated that testing was beneficial to the learning outcomes. Further analyses focussed on the role of potential moderator variables, a possible publication bias, and the dependency between effect sizes. The results are discussed in the context of applications in learning and teaching psychology.
Article
The testing effect refers to the finding that retrieval practice of previously studied information enhances its long-term retention more than restudy practice does. Recent work showed that the testing effect can be dramatically reversed when feedback is provided to participants during final recall testing (Storm, Friedman, Murayama, & Bjork, 2014). Following this prior work, in this study, we examined the reversal of the testing effect by investigating oscillatory brain activity during final recall testing. Twenty-six healthy participants learned cue-target word pairs and underwent a practice phase in which half of the items were retrieval practiced and half were restudy practiced. Two days later, two cued recall tests were administered and immediate feedback was provided to participants in Test 1. Behavioral results replicated the prior work by showing a testing effect in Test 1, but a reversed testing effect in Test 2. Extending the prior work, EEG results revealed a feedback-related effect in alpha/lower-beta and retrieval-related effects in slow and fast theta power, with practice condition modulating the fast theta power effect for items that were not recalled in Test 1. The results indicate that the reversed testing effect can arise without differential strengthening of restudied and retrieval practiced items via feedback learning. Theoretical implications of the findings, in particular with respect to the distribution-based bifurcation model of testing effects (Kornell, Bjork, & Garcia, 2011), are discussed.
Article
Two introductory psychology classes (N = 145) participated in a counterbalanced classroom experiment that demonstrated the spacing effect and, by analogy, the benefits of distributed study. After hearing words presented twice in either a massed or distributed manner, participants recalled the words and scored their recall protocols, reliably remembering more distributed than massed words. Posttest scores on a multiple-choice quiz covering points illustrated by the experiment averaged about twice the comparable pretest scores, indicating the effectiveness of the exercise in conveying content. Students' subjective ratings suggested that the experiment helped convince them of the benefits of distributed study.