https://www.scientificamerican.com/article/trying-to-forget-may-impair-memory/
Go ahead. Try it. What did you have
for breakfast last Tuesday? Oatmeal, eggs, waffles? Did you, perhaps, skip
breakfast because you didn’t hear your alarm go off or you took a little too
long in the shower? If you are like me, and most other humans for that matter, you
may draw a complete blank when asked these seemingly simple questions. If you
are like me, you may even be totally and utterly convinced of a particular
aspect of a situation that your memory tells you is true, but ends up being
dead wrong. If you are like me, you may wonder just how specific details become
lost in the routines of daily life. If you are like me, you may wonder why
exactly some particulars are salient and others become muddled in the sea of
memories that our brain is forced to process. If you are like me, you will be
intrigued to find out why we can or cannot remember whether or not we had
pancakes, a side of orange juice, and an apple for breakfast last Tuesday
morning.
In the article “Neural Correlates of
Reactivation and Retrieval-Induced Learning,” Bridge and Paller of Northwestern
University discuss how recall of recently learned information can be improved
via reactivation of this information, just like what you had for breakfast this
morning. They supported this theory with an experiment which involved three
trials that tested participants’ memory of 180 object-location associations
over 72 hours (in 24 hour increments). Participants were provided with a grid
in which an object would appear in the middle, and then be placed in a certain
location on the grid (see figure). They learned these associations until they could
correctly place all the objects twice. This simulates newly learned facts in
our everyday lives, such as how many pounds are in a kilogram, or how many
plays Shakespeare wrote. In trials 1 and 3, participants were asked to recall
spatial associations for all 180 items. However, in trial 2, participants were
only asked to place a subset of the items in their correct locations, while the
others merely flashed in the middle of the screen. The researchers hypothesized
that, because participants were being asked to recall the location of the items
in trial 2 with a greater frequency than the items not included in trial 2,
participants would demonstrate a greater accuracy of recall for those items in
trial 3. This means that the subjects’ memory was better for objects that they
had reactivated in their memories. As they had predicted, retrieval of the
items in session 2 led to significantly greater recall accuracy in trial 3 when
compared with the items that the participants had not been asked to recall in
trial 2. For those of us who remember studying history in grade school, this
makes sense. The more we recall new facts, such as the day the Constitution was
signed or the name of the Union general at the beginning of the Civil War, the
more readily we are able to recall them at a later time. Finally, we are
validated for those countless hours sitting at the kitchen table with our noses
buried in a history book!
Furthermore,
Bridge and Pallor also explored what happens if we retrieve information but
that information is actually inaccurate with respect to the information we had
actually learned in the first place. Imagine this, you are sitting at your
kitchen table studying history. You read in your book that the Constitution was signed
in1787, but your mom walks in and mistakenly declares that it was actually
signed in1776. You write this down on a notecard for further studying and you
ultimately get this question wrong on the test because you retrieved inaccurate
information. Bridge and Pallor found
similar results to this scenario. If participants incorrectly recalled a
location in trial 2, they were significantly more likely to place the item in
trial 3 near the incorrect trial 2 location than in the correct trial 1
location. Therefore, to this reader, it seems logical that inaccuracies in
memory may accumulate over subsequent recalls, potentially leading to a false
memory. It truly forces one to wonder how well the most vivid memories compare
to what had occurred in reality. Is our view of the past actually just a
product of numerous distortions?
However, what
happens when we deliberately try to suppress information? Is it actually possible
to forcibly forget? A recent study by Jesse Rissman addressed this exact
question. Participants were asked to memorize sets of word pairs, with one word
being linked to a set of retrieval tasks and the other being linked to a set of
suppression tasks. Participants were also shown a picture of an object in a
specific background (a teddy bear in a kitchen, for example) in between these
retrieval and suppression tasks and asked to relate the picture to the word
pair. Interestingly, when later asked to recall the object when given the location
without the object in it (i.e. just the kitchen), participants were
significantly more likely to correctly identify the object (i.e. teddy bear)
when the object/background pair was given between retrieval tasks than between
suppression tasks. Clearly, it is possible that forcible memory suppression
hinders future recall. This fact could possibly explain why people suffering
from PTSD oftentimes have issues with short-term memory, as they oftentimes repress their traumas.
Clearly, there is
no need to tie a ribbon around your finger the next time you have to remember
to send a birthday card to your grandmother or pick up some milk from the
grocery store. Just remember, constant and consistent retrieval is key! Maybe
you will even start to remember what you had to breakfast last Tuesday.
Works Cited
Bridge, Donna A. and Ken A. Paller. "Neural Correlates of Reactivation and Retrieval-Induced Distortion." Journal of Neuroscience 32.35 (2012): 12144-12155.
Sachan, Disna. "Trying to Forget May Impair Memory." Scientific American. N.p., 02 Aug. 2016. Web. 17 Oct. 2016
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