I woke up last week convinced that I could smell coffee. My husband, the coffee drinker in our household, was away for business and my 20-month-old son hasn’t yet discovered the substance so it seemed odd that there would be the familiar comforting aroma in the air. Within seconds of my waking up, however, it was gone. I’m not a coffee drinker, but I can easily be categorized as a coffee sniffer. I’d been craving a whiff last night before I went to bed. Was it possible that I’d dreamed up the aroma while asleep?
It’s possible, but it would make me part of a tiny minority. I often fall in love with things because of the way they smell — old books, roadside chai in India, a sandalwood box in which I keep my wedding ring, my son’s first onesie. While human beings can and do dream of odor, it’s proven that only very few of us — usually people attune to odors in everyday life — actually do.
In fact, it’s so infrequent that research on odors in dreams is choppy and incomplete at best. The first study was done in 1893 when Mary Whiton, an instructor at Wellesley College analyzed dream diaries kept by two volunteers over a six- to eight-week period. Her conclusions, then followed up in 1896, showed that odors show up in an estimated 15 percent of dreams. A hundred years would pass before anyone thought to study the subject again. In 1998 researchers at McGill found that while as many as 20.9 percent of women had odorous dreams, the number was only 2 percent for men.
More interesting, however, is the latest research, which shows that not only are odorous dreams possible, but what you smell before your head hits the pillow may be behind whether you wake up feeling happy or sad.
In a German study at the University Hospital, Mannheim, researchers conducted an experiment on fifteen women. When the women were in REM sleep (the phase where dreams are most likely to occur), they were exposed to three different odors three different times — once with hydrogen sulfide (which smells of rotten eggs), once with a neutral scent, and once with phenyl ethyl alcohol (which smells of a rose). A minute after being exposed to the odor, they were woken up and asked about their dreams.
Surprisingly, the women did not wake up recollecting smells of roses or rotten eggs. The sense of smell is closely associated with the brain’s limbic system, which is responsible for emotion and behavior. The brain handles scent differently than it does sound or touch and so several of the women in the study reported dreams about activities involving smells — cleaning toilets or walking through a garden — but not the smells themselves.
It could be why I woke up feeling happy and loved (and sniffing coffee) that morning last week and why baking oatmeal cookies before bed may just be a very good idea.