Do the blind have a more acute sense of smell?

April 26, 2010

An ongoing study by Mathilde Beaulieu-Lefebvre, a graduate student from the Universite de Montreal Department of Psychology, has debunked the myth that the blind have a more acute sense of smell than the sighted. Vision loss simply makes blind people pay more attention to how they perceive smells.

"If you enter a room in which coffee is brewing, you will quickly look for the coffee machine. The entering the same room will only have the smell of coffee as information," says Beaulieu-Lefebvre. "That smell will therefore become very important for their spatial representation."

The three-step study tested 25 subjects, 11 of whom were blind from birth. Participants answered a questionnaire and were subjected to two experiments: one where they had to differentiate 16 different perfumes using an olfactometer, another where they lay in a tomodensitometer to identify three smells: a rose, vanilla and butanol (a sweet alcohol).

"There is an urban legend that blind people have better smell than the sighted. We are proving this to be false," says Maurice Ptito, a professor at the Université de Montréal School of Optometry and Beaulieu-Lefebvre's thesis director. "However, the blind do set themselves apart when it comes to cognitive efforts."

Using functional imagery, the team determined that the blind use their secondary olfactory cortex more than the sighted when they smell. They also use the occipital cortex, which is normally used for vision. "That's interesting because it means the blind are recuperating that part of their brain," says Dr. Ptito. "We're not speaking of recycling per se, yet that part of the brain is reorganized and used otherwise."

This research could lead to concrete applications in the re-adaptation of the blind. "For instance, smells are very peculiar in shopping centers," says Beaulieu-Lefebvre. "A hair salon, a pharmacy and a clothing store each have their own distinctive scent. We could easily foresee developing re-adaptation programs for getting around in such places."

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dsl5000
not rated yet Apr 27, 2010
If these people are able to pay more attention on average than a non-blind person, it would appear as if their smell is more acute, no?

FYI neurons in their olfactory bulb/neuron in nose doesn't increase per se, but with so many neuronal connections to other parts of the brain like the occipital cortex, the likely hood of those neurons in the olfactory bulb undergoing pruning is less likely. Maybe they can look into that :)

The study should probably show if the sense of smell is more preserved by blind people vs non-blind over time.
antialias
not rated yet Apr 27, 2010
Uh huh..."We are proving this to be false" with a test group of 25/11 people.

I think not.

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