As part of the project, more than four dozen 6th graders were instructed to place rose-scented fragrance sticks on the desk where they studied their schoolwork and to place another rose-scented fragrance stick on the stand next to the bed where they slept at night. [...] The results, according to the study, indicated ‘a significant increase in learning success’ in the students who studied and slept with the same scent.
— Read more in Fragrance and deep sleep combo found to significantly boost learning at Slashgear, or see the original study How odor cues help to optimize learning during sleep in a real life-setting at Nature.