#2: Reading Research Articles
A., Kohler, M. J., Payne, J. D., & Drummond, S. A. (2017). The effects of
sleep restriction and sleep deprivation in producing false memories. Neurobiology
of Learning and Memory, 137107-113.
study is focused on the relationship between sleep restriction and sleep
deprivation on the formation of false memories. Its purpose was to determine by
experiment whether cognitive dysfunction caused by sleep loss during the
encoding process of memory has an impact on the formation of false memories.
The major findings are that partial and total sleep loss led to the same effects
on false memory and real verbal memory; participants did more poorly after
partial or total sleep loss on cued recognition-based false and real verbal
memory tasks, and that under free recall conditions sleep loss impacted participants’
ability to remember real, but not false memories; and that sleep loss had no
significant effect on a visual false memory task-supporting that sleep loss leads
to the dysfunction and decreased repair time of an online verbal associative
process in the brain.
this study was done, it was known that sleep loss has a negative impact on
basic elements of cognitive functioning, such as attention processing, response
inhibition, and working memory; as well as elements of higher cognitive
functioning, such as rule based learning, memory encoding, and the ability to
plan and follow through with intention. Sleep has also been suggested to play a
role in associative memory formation. It was also known that sleep loss reduces
the amount of information remembered by individuals both by negatively
impacting the capacity for encoding new memories and through the loss of
sleep-based benefits in terms of memory consolidation. Specifically in regards
to knowledge on false memories, it was known that false memories can occur
across all stages of memory processing, and that false memories can arise from
spreading activation in neural networks and self-referential encoding,
competing imagery during encoding, memory reactivation and generalization
during consolidation, or monitoring errors during retrieval. Furthermore, it
was stated that sleep has been found to reduce false memories when using
cognitive-based retrieval procedures, increase both correct recall and false
memory using recognition tasks, and generally increase both correct recall and
false memory when free memory recall procedures are used. Lastly, it was known
that sleep deprivation at memory retrieval has been linked with increased
endorsement of false memories, as has sleep deprivation at encoding.
variables studied were amount of sleep: 9 hours a night for six nights, sleep
deprivation of 30 hours, or 4 hours a night for 4 nights; and performance on
tasks: mood and sleepiness scales, a verbal false memory task (DRM), and a
visual false memory task after reaching the amount, or lack of, sleep they were
The hypotheses about these variables are:
partial and total sleep deprivation will not significantly differ in their
effects on real and false memory, all sleep loss will increase the rates of
false memory production, and that all sleep loss will increase false memory in
both verbal and visual modalities.
operational studies of the variables studied were as follows:
Amount of sleep was measured by being
monitored by polysomnography and interaction with the staff in the lab, and self-report
when at home.
Mood and sleepiness scales were measured by
participants being asked, “How _____ do you feel?” where the blank was
completed with the words: sad, happy, calm, anxious, relaxed, stressed, and
irritable. They then marked a spot on a 10cm long line corresponding to their
mood state, which had the terms “very little” and “very much” on either side.
It was scored by measuring the distance from “very little,” with small numbers correlating
to little feeling of the particular emotion and large numbers correlating to a
significant feeling of the particular emotion.
The verbal false memory task (DRM) was
measured by participants being presented with 3 sets of 12 words and then
completing a free recall test. The recall form was then taken out and the participants
saw another 2 sets of 12 words. In total there were a total of 4 “trials,” each
followed by a free recall testing. After the presentation of all lists, participants
performed a recognition memory test, each with contained 108 words-54 being previously
seen and 54 words being new. The previously seen words consisted of 6 randomly
selected words from each study list. The new words consisted of each of the 12
lures and 42 foils selected from unused DRM lists, and they were matched for
frequency, word length, and concreteness.
The visual false memory task was assessed by
participants being given 16 sets of 9 abstract shapes, each presented for 2.5
seconds each with an inter-trial interval of 3 seconds. Participants had to
indicate if each shape was old or new, and were told to give their answer as
quickly as possible without compromising accuracy.
participants in the study were 25 females and 19 males, with the average age
being 24.9 years old. They were all reported to be “normally functioning”
begin the procedure to test the study’s hypotheses, the participants adhered to
their regular sleep schedules for a week before the study began. Afterwards,
the researchers assigned a control group to continue with their normal sleep
patterns, but adding or subtracting sleep to schedules to all equal 9 hours so
all participants were receiving the same amount of sleep. The groups of partial
and total sleep deprivation were then determined by randomization, and order of
condition was counterbalanced. While participants were in the lab, actigraphy
was used to monitor the participants throughout the day, and polysomnography
was used to monitor participants while they were sleeping. Tests were then
administered 7 hours after the control group and partial sleep deprived
participants awoke, and 5 hours after the total sleep deprived participants
usually awoke (this difference was due to constraints not specified).
experimental method was used in this study because there was an independent
variable being manipulated, as well as a dependent variable being measured.
major results were that partial and total sleep deprivation led to the same
effects; in regards to verbal information, sleep loss led to decreased
recognition of both real and false memories, and reductions in recall of real
memory, but not recall of false memory; and sleep loss did not have a
significant impact on real or false memory for abstract shapes.
result of partial and total sleep deprivation having the same effects were
consistent with the researchers’ hypotheses; the second result of sleep loss
decreasing formation of false memories was the opposite of what was predicted,
and the third result was not consistent with the hypotheses since it was not
The researchers proposed that an alternative
explanation for the results is dysfunction during the encoding process,
retrieval process, or both, that occurred in a state of sleep deprivation. They
stated another alternative explanation could be that the lists used in testing
were not properly encoded in the first place, for the proposed reasons of
cognitive load or overtaxed memory systems. Further, the researchers said a
potential reason for discrepancies between their results and the results of
similar studies was due to the different tests used-which could possibly lead
to encoding and retrieving differences. The researchers recognized these
confounds and determined an extension of the study would be necessary to look
further into the tests used to produce the most accurate results.
think another possible alternate explanation is that some people might
naturally be better or worse at the tasks distributed than others; or
potentially that sleep restriction with tests being administered could cause
participants to act accordingly to how think they should.
The researchers suggested that future
researchers studying the same topic should selectively manage sleep amounts at
different stages of memory processing. They also recommended event-related
potentials to eliminate the possible differing effects of encoding and
retrieval processes. Further, they believe it would be beneficial to
incorporate a mixed neurophysiological and behavior design in the future.
I would suggest that the researchers
say that they are testing for something they aren’t
to avoid participants acting in a way they think they should if they know or guess what the study is about.