How can music help to strengthen our memories during sleep?

By Hae Young Yi, BC '23
Posted on September 14, 2023

If you’ve ever experienced a late night, caffeine-fueled study session cramming for an exam you’ve put off to the last minute, you may have faced the temptation to simply place your textbook under your pillow, sleep on it, and hope for the best (yes, this myth does indeed exist and you can find several Reddit threads on it!). There is no evidence supporting the claim that sleeping on a book will magically help you retain information, but studies have found it’s possible to improve memory consolidation using targeted memory reactivation (TMR). TMR is a technique where memories can be cued during sleep using a stimulus that was present when the memory was initially encoded. For example, smelling a book while reading a certain passage of text and then being presented with the same scent during sleep can reactivate the memory and allow it to be stored more effectively into long-term memory. This process could be explained by the system consolidation theory of memory (Born & Wilhelm, 2012): think of memories as first being encoded and stored in a neurological waystation, such as the hippocampus. They lie dormant there and patiently wait in line to be shipped off to their long-term residences in the brain. However, not every piece of information/memory you encode is worth storing in long term memory, so during sleep some items may be “lost” or forgotten. If the information lost is your best friend’s boyfriend’s roommate’s birthday, then it’s not a cause for concern, but if it’s an incredibly important definition to remember ahead of your psychology exam, you may be more inclined to hold onto this memory if you can. Here’s where targeted memory reactivation comes into play. Targeted memory reactivation helps bring specific memories to the front of this metaphorical line, effectively telling your brain, “Hey! This is important. I need to remember this!”, and thereby increasing their likelihood of being stored in long term memory. Whoo hoo! So… perhaps Reddit users are onto something here…

Active system consolidation relies on getting an appropriate amount of sleep, specifically slow wave sleep, in order for memories to be consolidated. This is especially salient for students as their ability to learn new material depends in part on the quality of sleep they receive. A study by Cousins, Sasmita, and Chee at Duke-NUS Medical School (2018) found that sleep deprivation (sleeping 5 hours a night for 5 consecutive nights) prior to learning new material in 15 to 18-year-olds significantly worsened their scores on a memory retrieval task compared to those who had not been sleep deprived (those who slept 9 hours a night for 5 consecutive nights). However, if you’re someone who is chronically sleep deprived, TMR has been suggested to be a tool to help combat the negative effects of sleep deprivation on learning and memory by biasing which memories are more likely to be stored in long term memory (Gao et al., 2020).

It was over these concerns of how chronic sleep deprivation could negatively impact student education and performance that inspired researchers Gao, Fillmore, and Scullin at Baylor University (2020) to construct a study testing the effects of targeted memory reactivation (TMR) on memory and conceptual learning. This was a shift in focus from previous TMR studies that only tested people’s memory of word /object lists - a fine way to measure memory, but less applicable to the average student/individual who is not tested on strict memorization. Gao et al. also chose music as the TMR cue because of its popularity as a memorization and study tool amongst students.

They recruited 50 undergraduate students with no prior economics backgrounds and instructed them to work through a self-guided, virtual college-level microeconomics lecture. Half of the students listened to classical music (the experimental TMR condition) and half listened to white noise (the control condition) while working. They then slept overnight in the laboratory where experimenters replayed either classical music or white noise when they entered slow-wave sleep. Results from an exam taken the next morning found that students who had undergone TMR (the classical music condition) had a higher probability of passing the exam (57.89% of TMR participants vs. 22.73% of control participants). The TMR group also scored 18.58% higher than the white noise group on integrative knowledge-transfer questions that required participants to apply learned concepts in novel ways. This improvement was seen even more drastically in female participants than male participants - a significant finding given experimental data showing women are more negatively affected by sleep deprivation than men (Goldestein-Piekarski et al, 2018; Conklin, Yao, Richardson, 2018). Finally, EEG analyses found that TMR participants had higher levels of frontal theta activity during sleep than control participants, suggesting this difference in brain activity is a method by which TMR can exert its positive effects. These improvements in conceptual integration were not present when participants returned 9 months later to take a similar exam, but in the short-term, TMR using music effectively improved exam performance and the ability to integrate college-level educational concepts. Although more work has to be done to determine the degree to which TMR may help sleep-deprived individuals, it remains an exciting and promising tool to help people consolidate memories more efficiently.

This raises the question: why is music an effective TMR tool? What broader connections does it have to memory and learning? From personal experience, you may have found that listening to certain music actually inhibits concentration and learning. Perhaps you find a song that’s incredibly upbeat makes you want to dance more than it makes you want to read “The Great Gatsby.” Or perhaps you find that listening to Adele is not the right mood for completing calculus problem sets, but Mozart is your jam. Studies have shown listening to music has a positive cognitive influence, especially when it comes to memory. Melody Chan and Yvonne Han (2022) found in a neuroimaging meta-analysis that classical music, but not other kinds of music, activated the limbic network - a collection of brain structures which has been implicated in mediating behavioral and emotional responses as well as learning and memory functions. However, other research has suggested it’s not necessarily the music itself that increases memory performance, but the effect music has on arousal and emotion, which in turn affects memory. Researchers Bottiroli, Russo, Vecchi, and Cavallini (2014) found that listening to classical music while performing various memory tasks improved overall performance. More specifically, listening to happy music led to increased brain processing speed. This suggests that listening to background music improves memory task performance by producing emotional states in the participants that activate the limbic system.

Apart from illustrating how associations between a stimulus, such as music, and memories can lead to more effective memory consolidation during slow wave sleep stimulus presentation, the experiment by Gao et al. highlights the wider applicability of TMR outside the laboratory. More generally, it demonstrates how scientific findings can be utilized outside academia to improve people’s daily lives - if listening to music while studying and sleeping is something you regularly do, you can take advantage of TMR to learn more efficiently, even if you don’t get the recommended amount of sleep. So go ahead! Blast your music while you study, whether it be Mozart, Childish Gambino, Frank Ocean, Frank Sinatra, or Ariana Grande - you name it! And perhaps you’ll find that although sleeping on your textbook doesn’t work to improve your memory, sleeping with your headphones on does.

Interested in listening to the music used in the study? Click the links below!

References

Born, J., & Wilhelm, I. (2012). System consolidation of memory during sleep. Psychological research, 76(2), 192–203. https://doi.org/10.1007/s00426-011-0335-6
Bottiroli S, Rosi A, Russo R, Vecchi T and Cavallini E (2014) The cognitive effects of listening to background music on older adults: processing speed improves with upbeat music, while memory seems to benefit from both upbeat and downbeat music. Front. Aging Neurosci. 6:284. doi: 10.3389/fnagi.2014.00284
Chan, M., & Han, Y. (2022). The functional brain networks activated by music listening: A neuroimaging meta-analysis and implications for treatment. Neuropsychology, 36(1), 4–22. https://doi.org/10.1037/neu0000777
Conklin, A. I., Yao, C. A., & Richardson, C. G. (2018). Chronic sleep deprivation and gender-specific risk of depression in adolescents: a prospective population-based study. BMC public health, 18(1), 724. https://doi.org/10.1186/s12889-018-5656-6
Cousins, J. N., Sasmita, K., & Chee, M. (2018). Memory encoding is impaired after multiple nights of partial sleep restriction. Journal of sleep research, 27(1), 138–145. https://doi.org/10.1111/jsr.12578
Gao, C., Fillmore, P., & Scullin, M. K. (2020). Classical music, educational learning, and slow wave sleep: A targeted memory reactivation experiment. Neurobiology of learning and memory, 171, 107206. https://doi.org/10.1016/j.nlm.2020.107206
Goldstein-Piekarski, A. N., Greer, S. M., Saletin, J. M., Harvey, A. G., Williams, L. M., &
Walker, M. P. (2018). Sex, Sleep Deprivation, and the Anxious Brain. Journal of cognitive neuroscience, 30(4), 565–578. https://doi.org/10.1162/jocn_a_01225
Grandner M. A. (2012). Sleep duration across the lifespan: implications for health. Sleep medicine reviews, 16(3), 199–201. https://doi.org/10.1016/j.smrv.2012.02.001
Thompson, W. F., Schellenberg, E. G., & Husain, G. (2001). Arousal, mood, and the Mozart effect. Psychological science, 12(3), 248–251. https://doi.org/10.1111/1467-9280.00345

Category: research-highlight