Presentation Details
Mapping and Remapping the Human Olfactory Perceptual Space

Sarah Cormiea, Jason Fischer.

Johns Hopkins University, BALTIMORE, MD, USA


In visual perception, words are said “jump-start” object recognition. Similarly, learning the label seems to transform an odor – to snap its perceptual features into sharper focus. Here, we present a novel method for mapping human olfactory perceptual space. We tested whether assigning labels to everyday odors alters their perceptual similarity. Participants reported the similarity of odors by dragging and dropping icons into a circular arena on a computer screen. In Session 1, stimuli consisted of sixteen unlabeled odors from common foods (e.g. onion, carrot, grapefruit, vanilla), delivered in opaque squeeze bottles. Subjects sniffed the odors and then arranged the icons on the screen, placing icons for similar-smelling items close together and different items farther apart. In Session 2, participants performed the same task, but this time with labels on the bottles identifying the odors. In Session 3, participants performed the arrangement task based on labels alone. Perceptual similarity was reliably correlated, demonstrating shared structure in participants’ perceived relationships among odors (N=20, leave-one-out correlation = 0.45; p<0.001). Further, the addition of labels in Session 2 altered the perceptual space in a reliable way that was not fully accounted for by a linear combination of the odor-only arrangements (Session 1) and the label-only arrangements (Session 3). Shifts in olfactory similarity space predicts that some odors will move farther apart and become more discriminable. Consistent with this hypothesis, we found improved discrimination in an odor mixture classification task with the application of labels (N=76, p = 0.041). These results suggest a reliable olfactory perceptual space that is systematically remapped with the application of labels.

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