Sleep learning used to be a pipe dream. A few examinations found that presenting scent signals during learning and specifically during slow-wave sleep increases learning success.
Now, a new study by the University of Freiburg has extended prior research offering evidence that this effect can also be achieved very quickly outside the lab.
Scientists performed a field study that involved 54 students from two 6th grade classes of a school in southern Germany. They were then asked to place rose-scented incense sticks on their desks at home while learning English vocabulary and on the bedside table next to the bed at night.
In another experiment, they also placed the incense sticks on the table next to them during a vocabulary test at school during an English test.
Scientists compared the test results in which no incense sticks were used during one or more phases. They found that the students remembered the vocabulary much better with a scent.
Study leader PD Dr. Jürgen Kornmeier, head of the Perception and Cognition Research Group at the Freiburg-based IGPP, said, “We showed that the supportive effect of fragrances works very reliably in everyday life and can be used in a targeted way.”
First author and student-teacher Franziska Neumann said, “The students showed a significant increase in learning success by about 30 percent if the incense sticks were used during both the learning and sleeping phases.”
“The results also suggest that the additional use of incense sticks during the vocabulary test promotes memory.”
Kornmeier said, “One particular finding beyond the seminal initial study was that the fragrance also works when it is present all night. This makes the findings suitable for everyday use. Previous studies had assumed that the fragrance needs to be only present during a particularly sensitive sleeping phase. However, since this sleep phase needs to be determined by an effortful measurement of brain activity using an electroencephalogram (EEG) in the sleep laboratory, this finding was not suitable for everyday use.”
“Our study shows that we can make learning during sleep easier. And who would have thought that our nose could help considerably in this.”
The study is published in the journal Scientific Reports.