Smelling America's Favorite Flower Helps People Learn Effortlessly During Sleep

Human beings have the ability to associate sounds with odors during sleep. A basic form of learning known as conditioning can occur during sleep. A new study reported that presenting odor cues while learning and selectively during slow-wave sleep can increase learning success.

Our memories play a vital role in allowing us to make future plans based on memorized past experiences, understand language and communicate effectively. We transfer about 10 Mbit of data per second from our eyes to the primary visual cortex of the brain. Other sensory modalities can also transfer information in a similar way.

The researchers at the University of Freiburg Medical Center sought to examine the effect of rose odor cues on the memory performance of students aged 11-12, given in different learning contexts including during sleep and memory retrieval.

The study included a couple of 6th-grade classes consisting of 31 eleven-year-olds and 22 twelve-year-olds in their normal school and home environments. They had one year of English classes before the study. To analyze the effect of odor cues, the researchers used vocabulary tests performed regularly in second language classrooms. In each class, the students were randomly assigned to the test and control groups.

They introduced vocabulary sets to all the students alongside school lessons without any odor cues. They, then, used rose odor cues to the test group while they were studying the English vocabulary at home. The study consisted of four steps: 1) initial presentation of the material at school; 2) learning at home; 3) sleep at home, and; 4) a vocabulary test at school.

The odor cues were applied via conventional commercially available incense sticks that were used in an unlit state.

“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,” Neuroscience news quoted the study’s lead author Franziska Neumann. “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.”

This study also showed learning during sleep can be made easier. The findings of the study also suggested that the additional use of the incense sticks during the vocabulary test promoted memory.