A recent study, which used rose scents to boost memory performance, investigated the role of smell in learning and memory. Olfaction is one of the oldest senses and links closely to parts of the brain that deal with emotion and memory.

Learning anything new relies on the conversion of details from the short-term memory into the long-term memory, which occurs through a process called consolidation. Studies showed that consolidation during sleep was vital for building memories and to this end, researchers have looked to scent. The authors confirmed that the strategic use of aromas while learning and during sleep possibly improved exam performance.

This study concluded that if we smell an aroma while we take on new knowledge and then sleep next to the source of that same odour, we would find it easier to recall the information at a later date. As the lead researcher, Dr. Jurgen Kornmeier explained, “We showed that the supportive effect of fragrances worked very reliably in everyday life and can be used in a targeted way.”

Ref: https://www.medicalnewstoday.com/articles/using-scents-to-boost-learning-during-sleep