High and low roads to odor valence? A choice response-time study.

Abstract

Valence and edibility are two important features of olfactory perception, but it remains unclear how they are read out from an olfactory input. For a given odor object (e.g., the smell of rose or garlic), does perceptual identification of that object necessarily precede retrieval of information about its valence and edibility, or alternatively, are these processes independent? In the present study, we studied rapid, binary perceptual decisions regarding odor detection, object identity, valence, and edibility for a set of common odors. We found that decisions regarding odor-object identity were faster than decisions regarding odor valence or edibility, but slower than detection. Mediation analysis revealed that odor valence and edibility decision response times were predicted by a model in which odor-object identity served as a mediator along the perceptual pathway from detection to both valence and edibility. According to this model, odor valence is determined through both a “low road” that bypasses odor objects and a “high road” that utilizes odor-object information. Edibility evaluations are constrained to processing via the high road. The results outline a novel causal framework that explains how major perceptual features might be rapidly extracted from odors through engagement of odor objects early in the processing stream.

The muted sense: neurocognitive limitations of olfactory language

“…A recent study suggested that when rapid behavioral responses were based on accessing the valence of a familiar odor, decision latencies were consistently longer (> 100 ms) and more variable compared to an object categorization task [29]. Similar results were obtained in a follow-up study where odors were subject to binary classifications based on their valence or object properties [30]. These findings suggest, at least for familiar smells, that odor objects manifest early in the processing stream [31].…”

Grounding language in the neglected senses of touch, taste, and smell

“…Pomp et al (2018) suggest the lack of piriform activation is due to the overall hedonicity of the olfactory sentences-which highlight a pleasant or unpleasant odour experience-and therefore activate secondary olfactory regions where odour valence is processed. However, since valence is thought to be the primary dimension by which odours are encoded (Khan et al, 2007;Yeshurun & Sobel, 2010;Zarzo, 2008;although see Olofsson et al, 2012;Olofsson, Bowman, & Gottfried, 2013), and odour language is also strongly encoded along this dimension (Levinson & Majid, 2014;Winter, 2016;Wnuk & Majid, 2014) piriform activation ought to be expected on a fully grounded perspective.…”

Odors: from chemical structures to gaseous plumes

“…However, competing research indicates that humans more likely identify the perceived identity of an odor in terms of its odorous quality (i.e. what it smells like) (Olofsson et al, 2012(Olofsson et al, , 2013. Additionally, Kumar et al (2015) created an alternative computational model to that of Snitz et al (2013) using descriptors of odor qualities and not judgements of valence, as well as measures of chemical structures to predict olfactory quality.…”