The study, published in the journal Scientific Reports, was conducted within pupils of two classes that learned English vocabulary, one of which learned it with the scent sticks while the other one did it without it.
"We showed that the supportive effect of fragrance works very reliably in everyday life and can be used in a targeted way," said study leader Jurgen Kornmeier from the University of Freiburg in Germany.
For the study, first author and student teacher Franziska Neumann conducted several experiments with 54 students from two 6th grade classes of a school in southern Germany.
The young participants from the test group were 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.
The results were compared with test results in which no incense sticks were used during one or more phases.
"The students showed a significant increase in learning success by about 30 per cent if the incense sticks were used during both the learning and sleeping phases," Neumann said.
The results also suggest that the additional use of the incense sticks during the vocabulary test promotes memory.
"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," Kornmeier said.
Previous studies had assumed that the fragrance needs to be only present during a particularly sensitive sleeping phase.
"Our study shows that we can make learning during sleep easier. And who would have thought that our nose could help considerably in this," Kornmeier said.