Free and cued identification of individual odorants in blind and sighted individuals

Abstract

Prior visual experience may affect olfactory identification of some odors, yet it remains unclear, whose qualities affect odor salience and familiarity in blindness. It seems very interesting, because such odors could be used to support the visually impaired individuals through novel solutions involving olfactory orientation and navigation. Here, we analyzed identification performance of 44 early blind and 52 sighted people focusing on differences in individual odorants included in a standardized olfactory identification test (SST). We hypothesized that blind people would outperform the sighted in the identification of unpleasant smells, as these odors are relevant for organism protection, and food odors, given blind people's intense odor focus in daily food evaluation. Our study consisted of cued and free identification tasks, each comprising one part of the popular Sniffin' Sticks identification test. We found no evidence of enhanced identification of unpleasant smells or food odors in blindness. Overall, our research suggests that visual impairment does not result in increased odor identification skills, especially in the case of suprathreshold cued odor identification task. Practical Applications Blindness is commonly associated with superior olfactory abilities, and this enhanced olfactory perception might be used to support the blind peoples' everyday functioning. We assumed that if odors of certain qualities were particularly salient and identifiable for people with blindness, these odors could be used to support the visually impaired individuals through novel solutions involving olfactory orientation and navigation. We tested whether visual impairment results in better identification of common odorants varying in pleasantness and edibility, as these qualities seem to be relevant for human vital functions. Our study suggests that blindness does not relate to particularly enhanced perception of suprathreshold odors. Therefore, further exploration is necessary to design systems supporting the daily functioning of the blind people through sensory cues.