A study in Science shows that wafting perfume under a person’s nose during slow-wave sleep helps the brain retain information learned during the day.
The study hints that odor cues could help with everyday mnemonic challenges, such as remembering names and faces.
First author Björn Rasch and colleagues had volunteers learn a 2D object location task (a card-sort test) while they got a blast of rose scent. Later, while they were sleeping, the volunteers were given two more shots of the fragrance at 30 second intervals. The next day all the volunteers were re-tested in the card sort test.
Those who smelled the roses during the initial training and later during SWS performed significantly better, remembering the location of 97 percent of the card pairs as compared to 85 percent for those who did not receive the scent or who only got it during training or during sleep alone.
But you don’t need to use a odor. You can use as well any sound and turn on it during SWS.