Many
research studies in the recent years have been interested in the process of
learning and memory within the brain. To
understand memory formation and consolidation researchers have been studying
both neuronal synapses through neurobiology methods and behavioral methods. It is one thing to see the formation of
strong synapses, but quite another to see the behavioral implications. Researcher Barbara Knowlton is a member of
the Psychology Department at the University of California, Los Angeles. Recently, she gave a talk about neural
substrates of desirable difficulties in motor sequence learning. According to the study, Knowlton found
statistical significance in the implementation of interleaved learning in terms
of memory consolidation. Knowlton’s
results suggest that cramming for an exam is not as effective of a study method
as studying throughout a longer period of time.
The concept of interleaved practice comes into play in the sense that
actually studying many different things over a period of time shows greater memory
retention. Therefore, the most effective
form of studying would not just include spreading the material across a period
of time, but also involves incorporating different subjects into every study
period. Retrieval practice is seen to be
beneficial to long-term learning. Doing
different things in between learning actually forces information retrieval at a
later time.
In a simple example and one of Knowlton’s
early studies, a group of participants underwent “blocked practice” while
another group underwent “interleaved practice”.
Blocked practice refers to learning information one group at a time. For example, it would be like memorizing the
list AAA, BBB, CCC, etc. Interleaved
practice is similar to memorizing the list ABC, BCA, CAB, etc. Each letter refers to a separate group or subject. According to Knowlton’s results, after a delay
of even ten minutes post memorization, the second group actually did much
better. At first, the performance of the
second group looked much worse, but after a longer period of time, the second
group seemed to have the best results. An
example involving a motor skill would be like playing the piano. It is better to learn three songs at the same
time in different parts than to learn one song fully and then move on to
another song.
Similarly, Knowlton and researchers
conducted an fMRI study on subjects who experienced both blocked and
interleaved practice. The fMRI results
showed that interleaved practice leads to better results than repetitive practice.
The disadvantage to interleaved practice is that constant retrieval of
information is very difficult; however, it does pay off in the long run! According to Knowlton, “The extra pain during
practice gives you more of a gain during retention” (quoted during talk). Results also showed that increased activation
in the superior frontal gyrus during interleaved practice was significantly
correlated with a subsequent behavioral benefit. When cerebellar function was manipulated with
tDCS, cerebellar activity was seen to be positively correlated with individual
transfer ability scores. The general
trend showed that cerebellar structure was beautifully suited to learning in
that plasticity at the synapses facilitate in the formation of strong connections.
The overall conclusions of this study demonstrate that interleaved practice is
beneficial for both retention and transfer of motor sequence learning.
A related study at Carnegie Mellon University
in the summer of 2013 analyzed synaptic formation and synaptic strength in
mice. This study was also published in the Journal
of Neuroscience. Mice with one
whisker were studied in different environments in order to analyze one brain
region at a time. (In mice, each brain region
controls the opposite whisker as a form of environmental perception. I find it
similar to how the right side of the brain controls the left side of the human
body and vice versa.) This method is
based off a specialized transgenic mouse model.
Previous research has shown that learning is best incorporated when it
is cumulative over a long period of time.
Many studies have also shown that synapses in the brain become much
stronger when exposed to a stimuli multiple times. However, this may not be the only case. According to neuroscientist Alison L. Barth, synapses
that are recently strengthened due to intense memorization or learning are
actually very fragile and vulnerable to increased stimulation. This activity could actually wipe out the
effects of learning. Data from Barth’s
study shows that synapses do strengthen with increased stimuli in the short
term; however, after a transitional phase predicted to involve consolidation of
the new information, the synapses quickly weaken!
Both Knowlton and Barth have similarities
in their studies in that they are looking beyond the effects of long-term, cumulative
practice in terms of memory and learning.
Knowlton focuses on the behavioral aspects while Barth studies the same
phenomenon from a neuronal perspective. Even
with the efforts of both Knowlton and Barth, there is still so much to be
learned in terms of memory formation. When
looking at future endeavors, I would love to see a combinatorial study using the
skill sets of both researchers. This
study could implement interleaved learning in terms of analyzing memory retrieval
ability as a whole and the same data could be analyzed for cues of synaptic strength
at varying periods of time. Overall,
both studies exemplify the importance of pushing beyond what previous research
shows in order to understand if there is more to the picture than what we may
actually see. Plus more research on
memory formation and consolidation means better exam scores, and I’m sure we
could all use a lot more of that!
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