A study conducted at Northwestern University has recently suggested that listening to sound cues for memories while sleeping can help people obtain better memory recall.
The study consisted of 12 subjects who were shown 50 images one at a time in particular locations on a computer screen. Each image was paired with a related noise. For example, researchers paired the sound of shattering glass with the image of a wine glass. After about an hour of memorizing the associated images, locations and sounds, the participants took naps for 90 minutes or less- long enough to enter a deep sleep, but not to enter rapid eye movement sleep, the phase in which dreams occur. It is during this deep, slow-wave sleep that occurs before the REM cycle that the brain is believed to reinforce factual memories.
Scientists played 25 of the 50 sounds while the participants slept. Upon awakening, the participants were then asked to recall the location of the 50 images. Participants' scores after napping were lower than those before napping, indicating a small memory loss over time. They were, however, able to more accurately place the 25 images whose associated sounds they had been exposed to while they slept, though none of the participants reported hearing any sounds while they were asleep.
Researchers believe that auditory stimuli may help trigger specific memories while the brain is replaying memories during sleep, thus reinforcing something already learned.
-compiled by Kaitlyn Hiltz