Harieshwar Vetri
One of our most impressive cognitive abilities is learning and remembering new things. Humans are thought to be the only beings capable of scientific learning, the ability to relate events that are separated by an interval of 60 seconds or more (Davis, 1986). If we were to lose this ability, would we lose a part of who we were? Almost certainly. Amnesia causes people to lose their ability to learn and retain new information while also affecting their memory to varying degrees (Amnesia - Symptoms and Causes, 2022).
Amnesia
from trauma is often temporary, in time the individuals will be able to recover
from this and regain all of their cognitive functions (Amnesia - Symptoms
and Causes, 2022). Nonetheless, they will have to deal with this loss of
function for that period and there are, unfortunately, no treatments or
interventions that can speed up this process. Fortunately, there is evidence
that shows that there is some retention, or at the very least recovery, of
these facilities very early in the recovery of the individual.
Various
studies with patients suffering from all kinds of amnesia have shown that
amnesiac patients can learn and become proficient in tasks in the short and
long term. Take, for example, the study by Nissen et al. (1989) involving the preservation
of learning in individuals suffering from Korsakoff’s syndrome. They were able
to realise and remember, albeit unconsciously, a series of letters that were
presented to them repeatedly. This information even remained present with them
after a substantial period.
Squire and Frambach (1990) conducted another study
involving two cognitive tasks both of which were related to keeping some sort
of variable at a certain level and were evaluated similarly allowing for
learning to occur. The participants were not told how the variable is
calculated at each step of the task and had to discern it themselves. The
amnesiac cohort consisted of individuals who had developed the condition
through various conditions such as anoxia and Korsakoff’s syndrome. Once again,
the amnesiac cohort displayed some characteristics of learning though there
seemed to be no evidence of practice when the task was carried out again a
month later due to a lack of declarative knowledge- the ability to recollect
facts and information.
Another
interesting study was conducted by Winter (2002). The amnesiac patient, referred
to as M.S., in this study had developed the condition due to anoxia which had
caused damage to the bilateral hippocampus. They were introduced to the game of
Tetris and taught the instructions and goals of the game. They were then
allowed to play and practice on their own time and every week their scores were
taken as part of a trial. When compared to a control group of 13 healthy individuals
M.S. was able to outperform the control group in week 2 and caught up to their
level of play by week 11, though the control group stopped giving measurements in
week 4. This discrepancy was attributed in part to M.S.’s slower reaction speed
but it can also be related to a lack of declarative knowledge causing him to have
to effectively relearn the game every session. Curiously, however, after the
study was complete, M.S. retained his access to the game and in time the
experimenters reported that he had “learned” the game’s mechanics and had far
exceeded both his own and the control group’s previous scores.
This
particular study is interesting because you can see evidence that some form of
learning and practice did in fact take place in patient M.S.’s case, though it
took him an undisclosed considerable amount of time to do so. This result relates
to a study once again involving amnesia and Tetris. Stickgold et al. (2000)
were conducting a study to document a reported effect where people who spent
large periods of time on a single activity would see images relating to these
activities as they fell asleep. The study involved 27 participants who were
asked to play 7 hours of Tetris over 3 days. 5 of the participants were
anterograde amnesiacs with bilateral medial temporal damage, meaning they were
unable to learn or even remember playing the game. Nonetheless, 3 of them
reported the very same imagery of Tetris blocks dropping at sleep onset. This
effect would go on to take the game’s name and be referred to as the Tetris
effect and spearhead further study into game transfer phenomena.
It
must be noted that in the last 3 studies all of the learning occurred with the
amnesiac’s declarative knowledge being impaired or even inaccessible. And yet
there is clear evidence of the participants displaying the ability to learn and
retain information, even if the individual themselves cannot consciously remember.
Stickgold et al. (2000) reason that there is some form of implicit memory
playing a role here.
While
our memory and ability to retain knowledge are often what makes us who our
brains are capable of repairing themselves from what would be far more debilitating
injuries. Humans seem to have an inherent curiosity and thirst for knowledge
and it would seem not even damaging or wholly removing their ability to store
what they have learnt will keep us from seeking and learning new things.
References
Amnesia - Symptoms and causes.
(2022, November 18). Mayo Clinic. https://www.mayoclinic.org/diseases-conditions/amnesia/symptoms-causes/syc-20353360
Davis, D. D. (1986). The uniqueness of
human learning. Medical Hypotheses, 21(2), 153–164. https://doi.org/10.1016/0306-9877(86)90005-8
Nissen, M. J., Willingham, D., &
Hartman, M. (1989). Explicit and implicit remembering: When is learning
preserved in amnesia? Neuropsychologia, 27(3), 341–352. https://doi.org/10.1016/0028-3932(89)90023-7
Squire, L. R., & Frambach, M. (1990).
Cognitive skill learning in amnesia. Psychobiology, 18(1),
109–117. https://doi.org/10.3758/bf03327224
Stickgold, R., Malia, A., Maguire, D.,
Roddenberry, D., & O’Connor, M. (2000). Replaying the Game: Hypnagogic
Images in Normals and Amnesics. Science, 290(5490), 350–353. https://doi.org/10.1126/science.290.5490.350
Winter, W. E. (2002). Acquisition of
Expertise on a Difficult Perceptual-Motor Task by an Amnesic Patient. Perceptual
and Motor Skills, 94(1), 59–67. https://doi.org/10.2466/pms.2002.94.1.59
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