Monday, April 26, 2010
An ongoing study by Mathilde Beaulieu-Lefebvre, a graduate
student from the Université de Montréal 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 blind person 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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University of Montreal
Thanks to University of Montreal for this article.