Sunday, February 1, 2015

The Blind Versus Sighted Smell-Off: Who Wins?

Smell has more than its share of bogus conventional wisdom. Case in point: the notion that blind people have a superior sense of smell by way of sensory compensation. I explored the evidence for this proposition in What the Nose Knows. It turns out the blind are no better than sighted people in terms of odor detection. While some studies find that the blind are better at naming odors, this is more likely due to cognitive factors (memory and practice) than to having a supersensitive nose. I concluded that superior smell in the blind is a canard, and I dubbed it the Helen Keller Fallacy.

My rejection of the CW would not have troubled the great lady herself. While acknowledging the importance of smell to her experience of the world, Helen Keller admitted that “I have not, indeed, the all-knowing scent of the hound or the wild animal.”

Since my book came out there have been additional studies. I blogged about one that claimed superior performance by the blind; it offered no challenge to my earlier conclusion.

Now another study has popped up. In a recently published paper, a group of German researchers asked “Do the blind smell better?” They tested 46 blind and 46 normal-sighted people with the Sniffin’ Sticks test kit. The kit provides three measures of smell ability: odor identification, odor discrimination, and olfactory threshold (i.e., sensitivity). The result: no difference between the groups overall, or on any single measure.

The myth remains busted.

The study discussed here is “Do the blind smell better?” by Christoffer Luers, Stefanie Mikolajczak, Moritz Hahn, Claus Wittekindt, Dirk Beutner, Karl-Bernd H├╝ttenbrink, & Michael Damm, published in European Archives of Oto-Rhino-Laryngology 271:1933-1937, 2014.

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