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Psychological Science
http://pss.sagepub.com/content/early/2013/02/20/0956797612457386
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DOI: 10.1177/0956797612457386
published online 20 February 2013Psychological Science
Renée K. Biss, K. W. Joan Ngo, Lynn Hasher, Karen L. Campbell and Gillian Rowe
Distraction Can Reduce Age-Related Forgetting
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DOI: 10.1177/0956797612457386
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The typical view of cognitive aging is one of decline, as seen,
for example, in lapses of attention, heightened distractibility,
and increased forgetting. Reports consistent with this view of
memory have come from studies using both objective mea-
sures (e.g., Balota, Dolan, & Duchek, 2000; Park et al., 2002)
and self-ratings (e.g., Commissaris, Ponds, & Jolles, 1998;
Halamish, McGillivray, & Castel, 2011). Laboratory studies of
attention regulation have also consistently yielded evidence of
older adults’ greater susceptibility to visual distraction. These
effects have been seen in a range of tasks, including tasks
involving problem solving (May, 1999), reading (Connelly,
Hasher, & Zacks, 1991; Duchek, Balota, & Thessing, 1998),
perceptual speed (Lustig, Hasher, & Tonev, 2006; Rabbitt,
1965), and working memory (Gazzaley, Cooney, Rissman, &
D’Esposito, 2005; Jost, Bryck, Vogel, & Mayr, 2011).
Older adults’ performance on these tasks is not only dis-
rupted by distraction; older adults also tacitly remember both
perceptual and conceptual aspects of distracting information
(Kim, Hasher, & Zacks, 2007; Rowe, Valderrama, Hasher,
& Lenartowicz, 2006), including statistical regularities among
distracting events (Campbell, Zimerman, Healey, Lee, &
Hasher, 2012). Older adults also implicitly transfer knowledge
of irrelevant information and thereby benefit (and sometimes
disrupt) their performance on subsequent intentional-learning
tasks (Campbell, Hasher, & Thomas, 2010; Thomas & Hasher,
2012). In contrast, younger adults do not implicitly use previ-
ously distracting information to aid performance, although
they sometimes use this information when they are explicitly
cued about its connection to the task at hand (Gopie, Craik, &
Hasher, 2011; Thomas & Hasher, 2012; but see Campbell
et al., 2010).
It has long been established that rehearsals, particularly dis-
tributed rehearsals, can improve memory among both younger
(e.g., Greene, 1987; Rundus, 1971) and older adults (Balota,
Duchek, & Paullin, 1989; Cohen, Sandler, & Schroeder, 1987).
Given the greater impact of distraction on older adults com-
pared with younger adults, along with the established benefits
of rehearsals, we asked whether exposure to distraction that
occurs between learning and a delayed memory test can reduce
older adults’ forgetting. We report the results from three exper-
iments indicating that the answer to this question is yes.
Corresponding Authors:
Renée K. Biss, Department of Psychology, University of Toronto, 100 St.
George St., Toronto, Ontario M5S 3G3, Canada
E-mail: renee.biss@utoronto.ca
Lynn Hasher, Department of Psychology, University of Toronto, 100 St.
George St., Toronto, Ontario M5S 3G3, Canada
E-mail: hasher@psych.utoronto.ca
Distraction Can Reduce Age-Related
Forgetting
Renée K. Biss1,2, K. W. Joan Ngo1,2, Lynn Hasher1,2,
Karen L. Campbell1,2, and Gillian Rowe1,3
1Department of Psychology, University of Toronto; 2Rotman Research Institute, Baycrest Centre for
Geriatric Care, Toronto, Ontario, Canada; and 3Neuropsychology and Cognitive Health Program,
Baycrest Centre for Geriatric Care, Toronto, Ontario, Canada
Abstract
In three experiments, we assessed whether older adults’ generally greater tendency to process distracting information can be
used to minimize widely reported age-related differences in forgetting. Younger and older adults studied and recalled a list of
words on an initial test and again on a surprise test after a 15-min delay. In the middle (Experiments 1a and 2) or at the end
(Experiment 3) of the delay, participants completed a 1-back task in which half of the studied words appeared as distractors.
Across all experiments, older adults reliably forgot unrepeated words; however, older adults rarely or never forgot the words
that had appeared as distractors, whereas younger adults forgot words in both categories. Exposure to distraction may serve as
a rehearsal episode for older adults, and thus as a method by which general distractibility may be co-opted to boost memory.
Keywords
aging, memory, attention, forgetting, intervention
Received 3/1/12; Revision accepted 6/19/12
Research Article
Psychological Science OnlineFirst, published on February 20, 2013 as doi:10.1177/0956797612457386
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2 Biss et al.
Experiment 1a
Younger and older adults studied a list of 20 words and recalled
each of the words twice—in an initial test after a brief delay
and again in a surprise memory test after a 15-min filled delay.
The critical task performed during the delay was a 1-back task
(Campbell et al., 2010; Rowe et al., 2006), in which partici-
pants saw a rapid stream of pictures and indicated whether
consecutive pictures were identical. Superimposed on the pic-
tures were irrelevant words or letter strings that participants
were instructed to ignore. These distractors included half of
the originally learned words, which created an opportunity for
the tacit rehearsal of those items.
Given the differences between younger and older adults in
both initial susceptibility to distracting information and subse-
quent use of that information (Campbell et al., 2010; Kim
et al., 2007; Rowe et al., 2006; Thomas & Hasher, 2012), we
predicted that older adults would show less forgetting of words
that reoccurred during the 1-back task than of words that did
not. On the basis of earlier work (e.g., Connelly et al., 1991;
Gazzaley et al., 2005; May, 1999; Rabbitt, 1965), we also
expected younger adults to effectively ignore the distracting
information and thus to show no difference between the for-
getting of items that were repeated as distractors and the for-
getting of those that were not.
Method
Participants. Information about the average age, level of edu-
cation, and vocabulary of the 38 younger (14 males, 24
females) and 40 older (13 males, 27 females) adults who par-
ticipated in this experiment is displayed in Table 1. All partici-
pants had learned English prior to the age of 5 and were free of
psychiatric or neurological illness. Younger adults were stu-
dents at the University of Toronto and received course credit
or monetary compensation in return for their participation.
Older adults were recruited from the community and received
monetary compensation in return for their participation. Data
from new participants were used to replace data from 3
younger and 3 older adults, 2 of whom (1 younger and 1 older
adult) had scores on the 1-back task that were more than 2.5
standard deviations below their group means, 1 of whom (an
older adult) reported feeling ill, and 2 of whom (1 younger and
1 older adult) reported both being aware of and using or avoid-
ing using the repeated words to facilitate performance (see the
Procedure section for details). On average, older adults had
more years of education than younger adults did, t(45) = 4.53,
p < .001; moreover, older adults had significantly better
vocabularies, as indexed by the Shipley (1946) vocabulary
test, t(69) = 6.44, p < .001, which would be expected from
increases in vocabulary across adulthood (e.g., Park et al.,
2002).
Materials. The studied list of words contained 20 concrete
nouns drawn from the MRC Psycholinguistic Database
(Coltheart, 1981). The list included 2 buffer words at the
beginning and 2 at the end to reduce primacy and recency
effects. The remaining 16 words comprised 8 that would be
repeated as distractors on the 1-back task and 8 that would not
be repeated. Across all participants in both age groups, each
word appeared equally often as a repeated word and as an
unrepeated word. Eight other words appeared as fillers in the
1-back task, along with 24 nonwords. All words were matched
for frequency of occurrence in written language (M = 50
instances per million words, SD = 17; Kučera & Francis, 1967)
and length (range = 4–7 letters, M = 5.3, SD = 1.0; Coltheart,
1981). Target pictures in the 1-back task consisted of 42 line
drawings selected from Snodgrass and Vanderwart (1980) that
were colored red to make them easily distinguishable from the
words.
Table 1. Participant Demographic Information
Age (years)
Experiment and group MRange
Years of
education (M) Vocabulary
Experiment 1a
Younger adults (n = 38) 19.6 (2.3) 18–27 13.3 (1.7) 30.9 (4.2)
Older adults (n = 40) 68.2 (4.5) 62–77 17.9 (6.2) 36.4 (3.2)
Experiment 1b
Older adults (n = 24) 67.1 (4.4) 61–77 16.7 (4.4) 36.1 (3.3)
Experiment 2
Younger adults (n = 30) 18.9 (1.9) 17–27 13.0 (1.4) 30.9 (4.5)
Older adults (n = 30) 67.4 (4.8) 60–77 16.3 (4.4) 35.0 (5.2)
Experiment 3
Younger adults (n = 36) 20.3 (2.0) 17–25 14.2 (1.8) 29.7 (3.7)
Older adults (n = 28) 68.6 (5.2) 60–78 16.7 (3.4) 36.0 (2.2)
Note: Vocabulary was measured using the Shipley (1946) vocabulary test; higher scores
indicate better vocabularies. Standard deviations are in parentheses.
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Distraction and Forgetting 3
Procedure. For study, words were presented on a computer
screen for 3,000 ms (interstimulus interval = 500 ms). Partici-
pants next were told to subtract 74 by 3s for 30 s and then to
recall aloud as many of the studied words as possible for 45 s.
They were not informed about the final test.
The 15-min retention interval began with a 5-min nonver-
bal task, followed by the 1-back task, in which participants
were instructed to press a key whenever two consecutive pic-
tures were identical and to ignore the superimposed words or
nonwords (Campbell et al., 2010; Rowe et al., 2006). Each
picture and its distracting word or nonword was presented for
1,000 ms (interstimulus interval = 500 ms). Each picture,
word, and nonword was presented twice during the task.
Repeated words were presented with the same picture on each
presentation, whereas all other distracting items appeared with
a different picture on each occurrence; this was done to ensure
that participants could not respond on the basis of the distract-
ing items rather than the pictures. Fifteen pictures repeated
on subsequent trials, requiring a 1-back response, and no
memory-list words appeared on these trials. There were 84 tri-
als in total, which occurred in the following sequence: 4 in
which pictures were presented alone, 8 in which pictures were
superimposed with nonwords, 64 in which pictures were
superimposed with either nonwords (32 trials), filler words
(16 trials), or the critical repeated words (16 trials), and 8 in
which pictures were superimposed with nonwords. Following
the 1-back task, participants completed a second nonverbal
filler task for 5 min.
At test, participants were reminded of the initial list and
were asked to recall as many words from it as possible for 45
s. A graded awareness questionnaire was then administered:
Participants were first asked whether they noticed a connec-
tion between any of the tasks. If participants reported that they
had noticed the repetition of study-list words in the 1-back
task, they were asked whether they had consciously tried to
use or avoid using these items during final recall. Data were
excluded from participants who both noticed the repetition of
items and reported deliberate use or avoidance of these items
to facilitate recall performance.
Results and discussion
Because scores for accuracy in the 1-back task were not nor-
mally distributed, we used nonparametric Mann-Whitney tests
across all experiments to examine differences between the two
age groups. Older adults were less accurate (median = 93%) in
detecting repeated pictures than were younger adults (median =
100%), U = 550, z = 2.34, p = .02, r = .26. Older adults were
also slower (M = 582 ms, SD = 110 ms) to respond on 1-back
trials in which repeated pictures appeared than were younger
adults (M = 516 ms, SD = 83 ms), t(76) = 2.95, p = .004,
d = 0.68.
Recall performance (see Table 2 for means) was analyzed
using an Age (younger, older) × Test Time (initial, final) ×
Word Type (repeated as distraction, unrepeated) mixed analy-
sis of variance (ANOVA) with test time and word type entered
as within-subjects variables. Overall, younger adults recalled
more than did older adults, F(1, 76) = 6.62, p = .01, ηp
2 =
.08, and recall decreased from the initial to the final test, F(1,
76) = 38.64, p < .001, ηp
2 = .34. However, both main effects
were qualified by a reliable three-way interaction of age, test
time, and word type, F(1, 76) = 4.08, p = .05, ηp
2 = .05. Older
adults showed less forgetting of words that were repeated as
distractors than of unrepeated words, F(1, 39) = 8.39, p = .006,
ηp
2 = .18. Younger adults, by contrast, showed equivalent for-
getting of repeated and unrepeated words, F < 1. With the
boost provided by repetition of studied items as distractors,
older adults’ final recall of repeated items did not differ from
that of young adults, t(76) = 1.02, p = .31, whereas typical age
differences were apparent for final recall of the unrepeated
items, t(76) = 2.96, p = .004, d = 0.67.
For ease of comparison across studies, data are shown in
Figure 1 as forgetting scores (the proportion of words recalled
in the initial test after study minus the proportion of words
Table 2. Proportion of Items Recalled
Initial recall Final recall
Experiment and group Unrepeated words Repeated words Unrepeated words Repeated words
Experiment 1a
Younger adults .41 (.21) .40 (.17) .36 (.22) .35 (.16)
Older adults .32 (.17) .33 (.18) .23 (.15) .31 (.18)
Experiment 1b
Older adults .32 (.09) — .26 (.11) —
Experiment 2
Younger adults .40 (.20) .38 (.22) .37 (.20) .31 (.20)
Older adults .35 (.18) .33 (.18) .27 (.18) .32 (.19)
Experiment 3
Younger adults .42 (.22) .40 (.18) .35 (.25) .36 (.20)
Older adults .29 (.19) .30 (.16) .20 (.14) .29 (.16)
Note: Standard deviations are in parentheses.
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4 Biss et al.
recalled after the delay). As is evident in the figure and in
Table 2, only older adults benefited from exposure to distrac-
tion: Clearly, presentations of relevant distracting information
minimized older adults’ forgetting and dramatically eliminated
age differences in younger and older adults’ recall of these
items, whereas typical age differences were seen in the recall
of unrepeated words.
Experiment 1b
A question left open by the first study is whether the benefits
of distraction seen among older adults occurred with or with-
out a cost to memory for the unrepeated items. This question
arises because of evidence that reexposure to a subset of
learned items can disrupt the retrieval of other items (e.g.,
Ratcliff, Clark, & Shiffrin, 1990). To address this issue, we
tested 24 additional older adults in a control condition in which
no study-list words appeared in the 1-back task. We compared
the performance of these participants with that of the older
adults in Experiment 1a who had been reexposed to words
from the list.
Method
Participants. A new sample of 24 older adult participants
(5 males, 19 females) was recruited in the same way our sam-
ple was recruited in Experiment 1a. There were no differences
in the average age, level of education, or vocabulary of partici-
pants in the two samples (see Table 1), ts < 1.
Materials and procedure. The sole way in which Experi-
ment 1b deviated from Experiment 1a was that the repeated
words used in the 1-back task in Experiment 1a were replaced
with eight new distractor words. These words matched those
in the previous word lists in their frequency (M = 54.5, SD =
26) and length (M = 5.3 letters, SD = 0.7; Coltheart, 1981).
Results and discussion
Older adults in Experiment 1b performed similarly to those in
1a on the 1-back task in terms of both accuracy (median =
93%) and response times (RTs; M = 589 ms, SD = 84), ps >
.76. Recall performance of these participants (Table 2), for
whom word type (repeated vs. unrepeated) was a dummy vari-
able, was then compared with that of the older participants in
the previous study using an Experiment (1a, 1b) × Test Time ×
Word Type ANOVA. The three-way interaction was reliable,
F(1, 62) = 5.00, p = .03, ηp
2 = .08. Consequently, we compared
participants’ forgetting in Experiment 1b with older adults’
forgetting in Experiment 1a. Forgetting was reduced for
repeated words in Experiment 1a compared with words in
Experiment 1b, which were never repeated as distractors,
F(1, 62) = 4.65, p = .03, ηp
2 = .07. In contrast, rates of forget-
ting of unrepeated items in the two experiments did not differ,
F < 1. Thus, we found no evidence that exposure to a subset of
studied words in Experiment 1a disrupted the retrieval of unre-
peated words. This finding strengthens the conclusion that
exposure to distracting but relevant information can boost the
recall performance of older adults.
ExperimentExperiment Experiment ExperimentExperimentExperiment 3
0.06 0.07 0.04 0.020.020.01
d 0.06 0.04 0.07 0.080.080.09
0.03 0.03815 0.036197 0.02195 0.043735 0.04
0.04 0.034989 0.042224 0.037950.0396830.037
Younger Adults Older Adults
−0.04
−0.02
0.00
0.02
0.04
0.06
0.08
0.10
0.12
0.14
Experiment 1a Experiment 2 Experiment 3 Experiment 1a Experiment 2 Experiment 3
Older AdultsYounger Adults
Forgetting Score
Repeated
Unrepeated
Fig. 1. Mean forgetting score (the proportion of words recalled in an initial test after study minus the proportion of
words recalled after a delay) as a function of age group (younger adults vs. older adults) and word type (repeated as
distraction vs. unrepeated) in Experiments 1a, 2, and 3. Error bars show 95% confidence intervals.
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Distraction and Forgetting 5
Except for evidence of an absence of age-related decline in
the recall of information about the gist of texts (e.g., Radvan-
sky, Zwaan, Curiel, & Copeland, 2001) and personally mean-
ingful information (e.g., prices of groceries, Castel, 2005;
safety-related information, May, Rahhal, Berry, & Leighton,
2005), we are unaware of findings comparable to those of
Experiment 1a demonstrating a reduction of forgetting in older
adults and an elimination of age differences in recall. Given
the novelty and potential importance of these findings to the-
ory and real-world applications, we conducted two conceptual
replications.
Experiment 2
In the 1-back task in Experiment 1a, participants responded
only on trials in which repeated pictures appeared. In Experi-
ment 2, participants responded on every trial, pressing one key
if a picture had repeated and another key if the picture had not
repeated. This procedure enabled us to compare RTs for unre-
peated pictures that were superimposed with study-list words
with RTs for those superimposed with control words. If older
adults are distracted by recently studied material, their
responses to pictures superimposed with repeated words
should be delayed. We also expected that Experiment 2 would
replicate the results of Experiment 1a, such that older adults
would show less forgetting of words repeated as distractors
during the 1-back task than of unrepeated items and younger
adults would show no difference in forgetting of the two types
of items.
Method
Participants. Thirty younger (10 males, 20 females) and 30
older (9 males, 21 females; see Table 1) adult participants
were recruited as in Experiment 1a. Data from 3 younger
adults who reported both awareness and deliberate use or
avoidance of the repeated words and from 2 older adults whose
scores on the 1-back task were more than 2.5 standard devia-
tions below the group mean were replaced with data from new
participants. Again, on average, older adults had more years
of education, t(35) = 3.86, p < .001, and larger vocabularies,
t(52) = 5.12, p < .001, as measured by the Shipley (1946)
vocabulary test.
Materials and procedure. Picture and word stimuli were the
same as those used in Experiment 1a, with the exception that
now three sets of eight items (repeated, unrepeated, and con-
trol distractor words), instead of two sets of eight items, were
counterbalanced across participants. The recall and filler tasks
were the same as in Experiment 1a.
As in Experiment 1a, distractors occurred twice on the
1-back task, and all items in the sets of repeated and control
distractor words occurred with the same picture on both
presentations.
Results and discussion
Overall, younger adults (median = 98%) were more accurate
on the 1-back task than were older adults (median = 95%),
U = 289, z = 2.40, p = .02, r = .31. RTs from the 1-back task
were trimmed by removing incorrect trials and responses with
latencies more than 2.5 standard deviations from each partici-
pant’s cell mean (this resulted in removal of 1.8% of younger
adults’ trials and 1.6% of older adults’ trials). We then com-
pared trimmed mean RTs for trials on which a repeated word
appeared with trials on which a control distractor appeared.
Among younger adults, there was no difference in RTs for
these two types of trials (repeated word: M = 497 ms, SD =
116; control distractor: M = 490 ms, SD = 108), t(29) = 1.08,
p = .29. In contrast, older adults responded more slowly on
trials in which previously studied items appeared (M = 695
ms, SD = 145) than on those in which control words appeared
(M = 671 ms, SD = 146), t(29) = 2.59, p = .02, d = 0.47. These
results suggest that older adults were more distracted by the
repeated items than the control items, a pattern consistent with
older adults’ general difficulty with ignoring distraction
(Campbell et al., 2010; Connelly et al., 1991; Lustig et al.,
2006; May, 1999; Rabbitt, 1965).
We analyzed recall using an Age × Test Time × Word Type
mixed ANOVA (see Table 2). The main effect of age was not
significant, F(1, 58) = 1.85, p = .18. There was a main effect of
test time, F(1, 58) = 29.44, p < .001, ηp
2 = .34, indicating for-
getting between the initial and final tests. Critically, the three-
way interaction of age, test time, and word type was significant,
F(1, 58) = 5.99, p = .02, ηp
2 = .09. This pattern of findings was
comparable to that of Experiment 1a: Older adults showed less
forgetting of words that were repeated as distractors than of
unrepeated words (see Fig. 1), F(1, 29) = 5.00, p = .03, ηp
2 =
.15, and younger and older adults did not differ in their final
recall of repeated words, t < 1. Younger adults showed no dif-
ference in the forgetting of repeated words and the forgetting
of unrepeated words, F(1, 29) = 1.48, p = .23, and there were
marginal differences between younger and older adults in the
final recall of unrepeated items, t(58) = 1.94, p = .057, d =
0.50. Thus, as in Experiment 1a, repeating words as distractors
benefited the recall of older adults, resulting in reduced forget-
ting across a delay and eliminating age differences in recall of
these items.
Experiment 3
In both previous studies, distraction occurred midway through
a 15-min delay. In Experiment 3, the same tasks were used, but
distraction occurred just before final recall. On the basis of the
impact of contextual similarity between rehearsal and recall
tasks reported in a number of studies (e.g., Howard & Kahana,
2002), we anticipated that even younger adults might benefit
from useful distraction that occurred immediately prior to
recall.
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6 Biss et al.
Method
Participants. Thirty-six younger adults (9 males, 27 females)
and 28 older adults (11 males, 17 females) participated in this
experiment (see Table 1). Data for 1 younger and 1 older adult
whose scores on the 1-back task were more than 2.5 standard
deviations below the group means and from 5 younger adults
who reported both awareness and conscious use or avoidance
of repeated words at final recall were replaced with data from
new participants. On average, compared with older adults,
younger adults had fewer years of education, t(38) = 3.49, p =
.001, and poorer vocabularies, as measured by the Shipley
(1946) vocabulary test, t(58) = 8.40, p < .001.
Materials and procedure. The materials and procedure in
Experiment 3 were similar to those used in Experiment 1a.
The sole change was the order of tasks in the 15-min interval
between initial and final recall: In this experiment, the 1-back
task occurred 10 min into the filled interval, immediately
before the final recall test.
Results and discussion
Younger adults were more accurate on the 1-back task
(median = 100%) than were older adults (median = 100%),
U = 366, z = 2.36, p = .02, r = .30. Although in the predicted
direction, the difference between 1-back RTs for younger
adults (M = 532 ms, SD = 67) and for older adults (M =
569 ms, SD = 123) was not significant, t(39) = 1.43, p = .16.
Recall performance was entered into an Age × Test Time ×
Word Type mixed ANOVA (see Table 2). As in Experiment 1a,
main effects of age, F(1, 62) = 9.73, p = .003, ηp
2 = .14, and
test time, F(1,62) = 19.33, p < .001, ηp
2 = .24, were reliable,
and there was a significant Test Time × Word Type interaction,
F(1, 62) = 15.21, p < .001, ηp
2 = .20. The three-way interaction
did not reach significance, F(1, 62) = 2.95, p = .09, ηp
2 = .05.
However, given the results of Experiments 1a and 2, we ana-
lyzed the data in Experiment 3 as we had in those experiments.
As in the previous experiments, older adults showed less for-
getting of items that had been repeated as distraction than of
unrepeated items, F(1, 27) = 11.82, p = .002, ηp
2 = .31. As a
result, there were no differences between younger and older
adults in final recall of repeated words, t(62) = 1.49, p = .14,
whereas these differences were evident for unrepeated words,
t(62) = 2.97, p = .004, d = 0.77.
For younger adults, there was a nonsignificant trend toward
less forgetting of words that had been repeated as distractors
compared with unrepeated words, F(1, 35) = 3.18, p = .08,
ηp
2 = .08. It is possible that the marginal benefit of repeated
distraction seen in younger adults in Experiment 3 (but not in
the previous experiments) resulted from the timing of the
1-back and recall tasks—that is, the contextual similarity
between reexposure to items as distractors and final recall
of those items may have produced this benefit (Howard &
Kahana, 2002).
Forgetting scores from Experiments 1a, 2, and 3 are shown
in Figure 1. As the figure makes evident, presenting studied
words as distractors minimized (Experiment 1a) or eliminated
(Experiments 2 and 3) older adults’ forgetting of these items
but had a minimal impact on the performance of younger
adults, who showed reliable forgetting of both types of words
across all three of the experiments.
General Discussion
The dramatic and consistent finding across these experiments
is that repeatedly presenting items as nontarget information—
that is, as distraction—minimizes and even eliminates age-
related forgetting. Across Experiments 1a, 2, and 3, older
adults showed little or no forgetting of words repeated as dis-
tractors but showed marked forgetting of unrepeated words.
By contrast, younger adults showed reliable forgetting of both
types of words, with differences in forgetting of the two types
showing a tendency to emerge only when reexposure to old
items on the 1-back task occurred just prior to recall. Perhaps
the most remarkable finding was that older adults’ recall of
words that had been repeated as distractors was actually equiv-
alent to that of younger adults—a finding that, to our knowl-
edge, has been reported in the aging and memory literature
only for studies in which important or emotionally salient
information was presented (Castel, 2005; May et al., 2005).
We suggest that reminders of information in the form of dis-
traction may keep that information accessible for older adults, a
phenomenon similar to maintenance rehearsal’s enabling items
to be recirculated into the focus of attention (Greene, 1987;
Rundus, 1971). Although there has been some debate over
whether shallow rote rehearsal has any influence on long-term
memory (e.g., Craik & Watkins, 1973; Greene, 1987), neuroim-
aging evidence has suggested that even simple phonological
rehearsal boosts memory performance (Davachi, Maril, & Wag-
ner, 2001). Elsewhere in the literature, younger and older adults
have been reported to exhibit equivalent benefits of repetition of
studied items (Balota et al., 1989; Cohen et al., 1987), although
in those cases, repeated items have been presented as target
items, not as distractors as in our experiments.
For older adults, the mnemonic benefit of repeated expo-
sure to items in the form of distracting information occurs in
the absence of intentions to rehearse or even awareness that
rehearsal is taking place. This effect is consistent with evi-
dence that implicit or automatic retrieval of past information
can work in concert with recollection to benefit episodic mem-
ory (Campbell et al., 2010; Jacoby, 1991; Thomas & Hasher,
2012). This implicit process may be particularly beneficial to
older adults because, unlike effortful mnemonic strategies, it is
unlikely to be disrupted by negative beliefs about aging and
memory (e.g., stereotype threat; Mazerolle, Régner, Morisset,
Rigalleau, & Huguet, 2012).
Implicit rehearsal of information in the form of distraction
may be applied as a practical method for improving memory
function in older adults, whereby rehearsal opportunities are
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Distraction and Forgetting 7
transferred to the environment (Craik, 1986; Lindenberger,
Lövdén, Schellenbach, Li, & Krüger, 2008). Of course, some
older adults may spontaneously seize on these opportunities—
for example, older adults have been shown to exhibit enhanced
prospective-memory performance when tested at home, where
cues in the environment may serve as reminders, rather than in
a lab (e.g., Henry, MacLeod, Phillips, & Crawford, 2004).
However, some older adults, such as those who have severe
memory impairments or are in nursing homes, have difficulty
implementing memory-compensation strategies (Dixon,
Hopp, Cohen, de Frias, & Bäckman, 2003). These individuals
may particularly benefit from environments that include non-
target reminders of important tasks (e.g., taking medication,
attending an appointment).
Using distraction as a rehearsal opportunity capitalizes on
older adults’ existing information-processing style, specifi-
cally, their reduced ability to suppress distraction (Hasher,
Zacks, & May, 1999), to boost their memory performance,
and thus differs from many existing interventions that focus on
making older adults’ cognitive performance more similar to
that of younger adults (e.g., Ball, Edwards, & Ross, 2007;
Hertzog, Kramer, Wilson, & Lindenberger, 2009; Winocur
et al., 2007). It may be fruitful for researchers and clinicians to
instead work with older adults’ natural patterns of cognition—
in particular, their tendency to process both relevant and irrel-
evant information—to improve memory rather than try to
make older adults think and remember like younger adults do.
Acknowledgments
The authors thank Elizabeth Howard for her assistance with data
collection.
Declaration of Conflicting Interests
The authors declared that they had no conflicts of interest with
respect to their authorship or the publication of this article.
Funding
This work was supported by Canadian Institutes of Health Research
Grant MOP89769 to L. H., an Alzheimer Society of Canada
Postdoctoral Award to G. R., and scholarships from the Natural
Sciences and Engineering Research Council of Canada to R. K. B.
and K. L. C.
References
Ball, K., Edwards, J. D., & Ross, L. A. (2007). The impact of speed of
processing training on cognitive and everyday functions. Journal
of Gerontology: Psychological Sciences, 62B, 19–31.
Balota, D. A., Dolan, P. O., & Duchek, J. M. (2000). Memory changes
in healthy older adults. In E. Tulving & F. I. M. Craik (Eds.),
The Oxford handbook of memory (pp. 395–409). New York, NY:
Oxford University Press.
Balota, D. A., Duchek, J. M., & Paullin, R. (1989). Age-related dif-
ferences in the impact of spacing, lag, and retention interval. Psy-
chology and Aging, 4, 3–9.
Campbell, K. L., Hasher, L., & Thomas, R. C. (2010). Hyper-
binding: A unique age effect. Psychological Science, 21, 399–
405. doi:10.1177/0956797609359910
Campbell, K. L., Zimerman, S., Healey, M. K., Lee, M. M. S., &
Hasher, L. (2012). Age differences in visual statistical learning.
Psychology and Aging, 27, 650–656. doi:10.1037/a0026780
Castel, A. D. (2005). Memory for grocery prices in younger and older
adults: The role of schematic support. Psychology and Aging, 20,
718–721. doi:10.1037/0882-7974.20.4.718
Cohen, R. L., Sandler, S. P., & Schroeder, K. (1987). Aging and mem-
ory for words and action events: Effects of item repetition and list
length. Psychology and Aging, 2, 280–285.
Coltheart, M. (1981). The MRC psycholinguistic database. Quarterly
Journal of Experimental Psychology, 33A, 497–505.
Commissaris, C. J., Ponds, R. W., & Jolles, J. (1998). Subjective for-
getfulness in a normal Dutch population: Possibilities for health
education and other interventions. Patient Education and Coun-
seling, 34, 25–32.
Connelly, S. L., Hasher, L., & Zacks, R. T. (1991). Age and reading:
The impact of distraction. Psychology and Aging, 6, 533–541.
Craik, F. I. M. (1986). A functional account of age differences in
memory. In F. Klix & H. Hagendorf (Eds.), Human memory and
cognitive capabilities (pp. 409–422). Amsterdam, The Nether-
lands: Elsevier.
Craik, F. I. M., & Watkins, M. J. (1973). The role of rehearsal in
short-term memory. Journal of Verbal Learning and Verbal
Behavior, 12, 599–607.
Davachi, L., Maril, A., & Wagner, A. D. (2001). When keeping
in mind supports later bringing to mind: Neural markers of
phonological rehearsal predict subsequent remembering. Jour-
nal of Cognitive Neuroscience, 13, 1059–1070. doi:10.1162/
089892901753294356
Dixon, R. A., Hopp, G. A., Cohen, A., de Frias, C. M., & Bäckman, L.
(2003). Self-reported memory compensation: Similar patterns in
Alzheimer’s disease and very old adult samples. Journal of Clini-
cal and Experimental Neuropsychology, 25, 382–390.
Duchek, J. M., Balota, D. A., & Thessing, V. C. (1998). Inhibition
of visual and conceptual information during reading in healthy
aging and Alzheimer’s disease. Aging, Neuropsychology, and
Cognition, 5, 169–181.
Gazzaley, A., Cooney, J. W., Rissman, J., & D’Esposito, M.
(2005). Top-down suppression deficit underlies working memory
impairment in normal aging. Nature Neuroscience, 8, 1298–
1300.
Gopie, N., Craik, F. I. M., & Hasher, L. (2011). A double dissociation
of implicit and explicit memory in younger and older adults.
Psychological Science, 22, 634–640. doi:10.1177/0956797611
403321
Greene, R. L. (1987). Effects of maintenance rehearsal on human mem-
ory. Psychological Bulletin, 102, 403–413. doi:10.1037/0033-
2909.102.3.403
Halamish, V., McGillivray, S., & Castel, A. D. (2011). Monitoring
one’s own forgetting in younger and older adults. Psychology and
Aging, 26, 631–635. doi:10.1037/a0022852
at UNIV TORONTO on June 28, 2013pss.sagepub.comDownloaded from
8 Biss et al.
Hasher, L., Zacks, R. T., & May, C. P. (1999). Inhibitory control, circa-
dian arousal, and age. In D. Gopher & A. Koriat (Eds.), Attention
and performance XVII (pp. 653–675). Cambridge, MA: MIT Press.
Henry, J. D., Macleod, M. S., Phillips, L. H., & Crawford, J. R. (2004).
A meta-analytic review of prospective memory and aging. Psy-
chology and Aging, 19, 27–39. doi:10.1037/0882-7974.19.1.27
Hertzog, C., Kramer, A. F., Wilson, R. S., & Lindenberger, U. (2009).
Enrichment effects on adult cognitive development. Psychologi-
cal Science in the Public Interest, 9, 1–65.
Howard, M. W., & Kahana, M. J. (2002). A distributed representa-
tion of temporal context. Journal of Mathematical Psychology,
46, 269–299.
Jacoby, L. L. (1991). A process dissociation framework: Separating
automatic from intentional uses of memory. Journal of Memory
and Language, 30, 513–541.
Jost, K., Bryck, R. L., Vogel, E. K., & Mayr, U. (2011). Are old adults
just like low working memory young adults? Filtering efficiency
and age differences in visual working memory. Cerebral Cortex,
21, 1147–1154. doi:10.1093/cercor/bhq185
Kim, S., Hasher, L., & Zacks, R. T. (2007). Aging and a benefit of
distractibility. Psychonomic Bulletin & Review, 14, 301–305.
Kučera, H., & Francis, W. N. (1967). Computational analysis of
present-day American English. Providence, RI: Brown Univer-
sity Press.
Lindenberger, U., Lövdén, M., Schellenbach, M., Li, S.-C., &
Krüger, A. (2008). Psychological principles of successful
aging technologies: A mini-review. Gerontology, 54, 59–68.
doi:10.1159/000116114
Lustig, C., Hasher, L., & Tonev, S. T. (2006). Distraction as a deter-
minant of processing speed. Psychonomic Bulletin & Review, 13,
619–625.
May, C. P. (1999). Synchrony effects in cognition: The costs and a
benefit. Psychonomic Bulletin & Review, 6, 142–147.
May, C. P., Rahhal, T., Berry, E. M., & Leighton, E. A. (2005). Aging,
source memory, and emotion. Psychology and Aging, 20, 571–
578. doi:10.1037/0882-7974.20.4.571
Mazerolle, M., Régner, I., Morisset, P., Rigalleau, F., & Huguet,
P. (2012). Stereotype threat strengthens automatic recall and
undermines controlled processes in older adults. Psychological
Science, 23, 723–727. doi:10.1177/0956797612437607
Park, D. C., Lautenschlager, G., Hedden, T., Davidson, N. S., Smith,
A. D., & Smith, P. K. (2002). Models of visuospatial and verbal
memory across the adult life span. Psychology and Aging, 17,
299–320. doi:10.1037//0882-7974.17.2.299
Rabbitt, P. (1965). An age-decrement in the ability to ignore irrel-
evant information. Journal of Gerontology, 20, 233–238.
Radvansky, G. A., Zwaan, R. A., Curiel, J. M., & Copeland, D. E.
(2001). Situation models and aging. Psychology and Aging, 16,
145–160.
Ratcliff, R., Clark, S. E., & Shiffrin, R. M. (1990). List-strength
effect: I. Data and discussion. Journal of Experimental Psychol-
ogy: Learning, Memory, and Cognition, 16, 163–178.
Rowe, G., Valderrama, S., Hasher, L., & Lenartowicz, A. (2006).
Attentional disregulation: A benefit for implicit memory. Psychol-
ogy and Aging, 21, 826–830. doi:10.1037/0882-7974.21.4.826
Rundus, D. (1971). Analysis of rehearsal processes in free recall.
Journal of Experimental Psychology, 89, 63–77.
Shipley, W. C. (1946). Institute of Living Scale. Los Angeles, CA:
Western Psychological Services.
Snodgrass, J. G., & Vanderwart, M. (1980). A standardized set of 260
pictures: Norms for name agreement, image agreement, familiar-
ity, and visual complexity. Journal of Experimental Psychology:
Human Learning and Memory, 6, 174–215.
Thomas, R. C., & Hasher, L. (2012). Reflections of distraction in
memory: Transfer of previous distraction improves recall in
younger and older adults. Journal of Experimental Psychol-
ogy: Learning, Memory, and Cognition, 38, 30–39. doi:10.1037/
a0024882
Winocur, G., Craik, F. I. M., Levine, B., Robertson, I. H., Binns,
M. A., Alexander, M., . . . & Stuss, D. T. (2007). Cognitive reha-
bilitation in the elderly: Overview and future directions. Journal
of the International Neuropsychological Society, 13, 166–171.
at UNIV TORONTO on June 28, 2013pss.sagepub.comDownloaded from
