Listen to Music While Studying & Napping

Continuing on the theme of neuroscience and cognitive psychology researchers trying to understand better the function of sleep and dreaming, I've just read another really interesting article in the New York Times (I have an email alert set up for articles containing the term "brain").  The article, "Sounds During Sleep Aid Memory, Study Finds", reports on a study by Rudoy et. al. at Northwestern University that was recently published in the journal Science.  The findings suggest that individual memories can be improved when subjects hear sounds associated with those memories during a nap.

The memory task used in this study involved teaching subjects the correct location of 50 different icons on a computer screen.  Icons - small pictures of a cat or a tea kettle - were associated with relevant sounds (for example, a "meow" sound was played when the picture of the cat was on the screen).  The subjects then took a nap (less than 90 minutes of sleep), during which they were monitored via EEG to track their sleep stage.  During the nap, some subjects heard only white noise, while some other subjects were (unknowingly) exposed, during "slow-wave" sleep, to 25 of the sounds they'd heard during the picture location learning task.  After the nap, subjects were tested for their ability to place icons on the screen.

Subjects who, during their nap, had heard the sounds associated with the icons performed significantly better in the memory task than subjects who heard only white noise during the nap.  EEG patterns were measured between the two groups, and confirmed that there was a significant difference between the electrical activity of their brains.  Though not exhaustive, the researchers performed a variety of control experiments to determine whether or not the sounds played during slow-wave sleep were the causal factor in the improved performance of the subjects who heard them, and it seems reasonable to infer that they were.

I would like to see some continued research on the importance of icon-sound relevance relative to task performance post-nap.  In other words, would performance on the task be as improved if subjects had heard an "irrelevant" sound for each icon - say, a car horn honking when the icon of the cat was displayed?  Of course, it would also be great to see further research on different types of memory and learning tasks and potential improvements in performance by associating sensory experiences (sound, smells) during the learning process and during sleep following that learning experience.  I am also curious about the utility of listening to music while studying, and then listening to that same music while napping.  In the mean-time, so long as the music we choose doesn't distract from learning or from sleep, it would seem reasonable to suggest that memory task performance may increase as a result.

Dream Work

A recent article in the New York Times suggests that dreams are the phenomenological result of the brain exercising itself in preparation for its next waking state.  This idea of dreaming as a "protoconscious state", proposed by Dr. Hobson, a psychiatrist at Harvard University who focuses on studying sleep, adds to the body of literature that frames the brain as an organ that does work.  Much like muscles need exercise to function well, so, apparently, does the brain.  This view, in my opinion, supports similar findings that the brain, again like muscle, requires time after exertion to return to its resting state.  Finding an educational application for this view of the brain's need for exercise to be highly functional is fairly straight-forward: we should introduce new ideas and concepts over time, in ways that the student finds engaging and authentic, so that the brain will have an opportunity to practice its work with this new material during its exercise time.

Cognitive Recovery Time

Researchers at the University of Cambridge have recently published findings in PLoS One that demonstrate the brain's need for a period of "down-time" after a challenging cognitive task in order to return to it's resting state. Barnes and colleagues continuously monitored their subjects' brain activity using fMRI, first having the subject relax for a bit more than 9 minutes, then having the subject perform a cognitive task for 9 minutes, and finally having the subject relax for almost 19 minutes. The cognitive task employed in this experiment was the widely used "n-back" memory game, in which subjects are shown two co-varying stimuli (generally a set of numbers that appear in different locations in a grid) and are challenged to respond correctly when the set of stimuli is a repeat of the set presented "n" times ago. In the version of "n-back" used here, the numbers ranged from 1 to 4 and appeared in a 4-quadrant grid; "n" was either 1 or 2 for different subjects.

Barnes et. al. found that the brain, like the heart, does not simply return to it's resting state immediately following activity. In this experimental design, the brain took approximately 6 minutes to return to its resting state following the task; although there was no statistically significant difference in recovery times between the n=1 and n=2 subjects, the data did indicate that the brain took more time to recover when the cognitive task was more demanding. As the researchers point out in the final paragraph of the discussion, these findings help to clarify further research questions, including testing the performance of subjects engaging in a new cognitively demanding task following a previous task, but before the brain returns to its resting state. For those of us involved in education as classroom teachers or as administrators in charge of the daily schedule of classes for students, this line of research should prompt us to reflect on how we structure the use of time within the classroom, as well as how much time we afford students to return to their resting state in between classes.

Barnes A, Bullmore ET, Suckling J, 2009 Endogenous Human Brain Dynamics Recover Slowly Following Cognitive Effort. PLoS ONE 4(8): e6626.doi:10.1371/journal.pone.0006626