Each nostril communicates more directly with a specific hemisphere of the brain, according to Science IQ. Researchers at Monell Chemical Senses Center, which studies the sense of smell, showed in an experiment that the left nostril communicates with the left hemisphere and the right nostril with the right hemisphere.
The left hemisphere contains the brain's dominant language centers, and study participants were slightly better at correctly identifying smells by name when inhaling through the left nostril. When participants inhaled through the right nostril, they considered odors to be more pleasant. That result is because the right hemisphere processes certain kinds of emotions, according to Science IQ.