I predict sales of white noise machines to increase in the near future.
In the human brain a network of neurons are often activated together. The collective rise and fall of activity of the network produces oscillations, the lines we see in an EEG. At different times the brain oscillates at different frequencies. During sleep the brain produces slow, <1 Hz oscillations – hence the term “slow-wave sleep” – and these oscillations are thought to be important for consolidating memories. The idea that the scientists at the University of Tübingen in Germany wanted to test was whether or not auditory stimulation that boosted the slow-wave oscillations also boosted memory.
The study included 11 people who learned word associations right before they went to bed. Their word assocaition memory was tested before they went to sleep and then again the following day. While they slept, they were played short durations of pink noise, a hissing sound similar to white noise. Importantly, the pink noise sounds were timed to the sleeping person’s “slow-wave” brain oscillations. When the individuals received the pink noise stimulation they were able to remember twice as many word associations than without the stimulation. When they repeated the experiment with pink noise that was not synchronized to the slow-waves, they saw no improvement in memory.
Monitoring the brain waves with EEG, the researchers also saw that the sound stimuli actually boosted the ongoing slow-wave oscillations. This led the researchers to suggest that pink sound stimulation could not only boost memory, but it might also help people sleep better.“The beauty lies in the simplicity to apply auditory stimulation at low intensities,” Jan Born, of the University of Tübingen and coauthor of the study, said in a press release. “An approach that is both practical and ethical, if compared for example with electrical stimulation.”
Others have tried to boost memory by stimulating the brain into synchronized, oscillating activity. Rhythmic electrical, magnetic and sound stimuli had all been previously used but with no effect. The current method worked, the authors suggest, due to the fact that they synchronized their sound stimulation to the natural oscillations of slow-wave sleep simultaneously going on in the brain.
And more than just allowing us to boost our memory while we get a better night’s rest, the authors suggest that similar auditory stimulation might work to enhance other brain rhythms that occur while we’re awake, such as the oscillations involved in regulating attention.
Of course, this only works if you’re not distracted by the constant, pulsating sound being played in your ear.
So I have to modify my initial suggestion. You not only have to play sounds, but you have time the sounds with the EEG device you’re wearing. But even EEG devices are becoming user-friendly. So much for Mozart For Babies, here’s to EEG Hits For Adults.