Perceptual Rivalry: Nostrils Alternate To Process Competing Odors
When the nose encounters two different scents simultaneously, the brain processes them separately through each nostril in an alternating fashion.
For the study, 12 volunteers sampled smells from two bottles containing distinctively different odors. One bottle had phenyl ethyl alcohol, which smells like a rose, and the other had n-butanol, which smells like a marker pen. The bottles were fitted with nosepieces so that volunteers could sample both scents simultaneously — one through each nostril.
During 20 rounds of sampling, all 12 participants experienced switches between smelling predominantly the rose scent and smelling predominantly the marker scent. Some experienced more frequent and drastic switches than others, but there was no predictable pattern of the switch across the whole group of volunteers or within individuals.
Chen said this “binaral rivalry” between the nostrils resembles the rivalry that occurs between other pairs of sensory organs. When the eyes simultaneously view two different images — one for each eye — the two images are perceived in alternation, one at a time. And when alternating tones an octave apart are played out of phase to each ear, most people experience a single tone that goes back and forth from ear to ear…. (more @ ScienceDaily)
