for National Geographic News
What you smell may influence emotions in your dreams, according to a new study.
When researchers gave dreaming subjects whiffs of rose scent, the subjects reported rosier dreams. The scent of rotten eggs, on the other hand, provoked unpleasant dreams, the study found.
The different scents were not incorporated literally into a person's dreams, said study author Boris Stuck of the University Hospital Mannheim in Germany.
"There was hardly any kind of a dream dealing with smelling and tasting," he said.
Rather, the pleasant odor appeared to affect the subjects' emotional ratings of their dreams.
(Related: "'Brain Reading' Device Can Predict What People See" [March 5, 2008].)
Strong Emotional Impact
The sense of smell is known to be closely associated with the brain's limbic system, which governs emotion and behavior.
"If odor has a strong effect on your emotions when you're awake, it makes sense for it to have a strong effect on your emotions when you're asleep," said Stuck, who presented the research Sunday in Chicago at the annual meeting of the American Academy of Otolaryngology—Head and Neck Surgery. The findings have not been published.
Stuck and his colleagues studied the effects of rose and rotten-egg odors on 15 healthy women in their 20s. Young women have been shown to have the best sense of smell, they said.
Tubes were taped to the subjects' nostrils, linking them to olfactometers. The devices pumped constant streams of air into their noses so a gust of odor would not wake them.
The subjects' brain activity was also being monitored. When they reached the rapid-eye-movement (REM) stage of sleep, when most dreams occur, a shot of scent was administered via the olfactometer for ten seconds.
SOURCES AND RELATED WEB SITES