The labeled dissimilarity scale: A metric of perceptual dissimilarity

Abstract

Fundamental to the concept of psychological distance is the idea that confusability allows discovery of the perceptual relationships between objects, which provides understanding of the underlying principles that govern the functioning of a system. Thus, judgments of dissimilarity (conceptually proportional to the inverse of confusability) may provide insight into the elusive underlying quality-coding mechanisms in that sensory system. In the present experiments, a labeled dissimilarity scale (LDS) that reflects the magnitude of odorant dissimilarity was developed in a fashion similar to that reported by Green (Green, Shaffer, & Gilmore, 1993).This scale was produced by rating the perceptual intensity implied by adverbs describing different levels of dissimilarity, and then attaching those descriptors to appropriate locations on a numerical scale. The usefulness of the scale was demonstrated by its ability to produce visual color space with ratings of dissimilarity of Munsell color chips. The stability and reliability of the LDSwas evaluated by comparing it with the traditional scaling technique of magnitude estimation (ME). It was found that the scales produced similar ratings of odorant dissimilarity and showed a similar susceptibility to the effects of contrast convergence. However, the coefficients of variation of dissimilarities rated with MEwere much higher than those produced with the LDS. The subjects also dealt with the LDSwithout the anxiety that usually accompanies first-time users of ME. The LDS provided stable ratings of odorant dissimilarity and preserved the inferred ratio scale properties of ME.The concept of psychological distance, as embodied by dissimilarity between stimuli, has proven useful in the understanding of many perceptual and cognitive processes. Investigations of dissimilarity take a number of forms, including errors in identification that are often summarized in confusion matrices (actually a measure of confusability), measures of discrimination, and direct scaling of perceptual similarity/dissimilarity. Regardless of the form, the premise of investigations of psychological distance is that dissimilarity allows for the discovery ofthe psychological or perceptual relationships between objects, thus suggesting the principles that govern the functioning of a system.A prime example of the utility of the concept of psychological distance can be found through the evaluation of color vision in normal and colorblind people. It is a simple task to ask people with normal color vision to rate the degree of dissimilarity between the hues of variousThe authors express their gratitude to Maxwell Mozell and Lawrence Marks, both of whom offered excellent advice on an earlier draft of this paper. The authors also thank the reviewers of this article, particularly Barry Green, for their helpful comments on earlier drafts of the manuscript. Experiment 2 was presented at the 1997 International Symposium of 01faction and Taste, with the abstract of that presentation published in

Categorizing Smells: A Localist Approach

“…Conversely, if the size of the set of odorants determines whether dimensions can emerge, then criteria by which odors are compared should be expected to change if the set of odors changes. This is exactly what is found: Changing as little as one single odor in the set of odors under examination (Kurtz, White, & Hayes, 2000) can change the criteria used for comparing these smells.…”

How we talk about smells

“…Which comparison class is considered also affects the choice of similarity criteria (Jraissati & Deroy, 2021, pp. 5–8, 13–15; see also Kurtz et al, 2000; Wise et al, 2000). Since our smell reports are plausibly a linguistic expression of our smell categorisations, an account of such reports where similarities, respects and comparison classes play a key role fits well with this research.…”

Smell identification and the role of labels

“…Moreover, research on olfactory categorisation shows that, partly because of the qualitative complexity of smells, which and how many categories subjects form depends on which similarity criteria and comparison class they deem salient in the context (e.g. Jraissaty & Deroy, 2021; Kurtz et al, 2000;Wise et al, 2000;Chastrette, 1998). As highlighted in a methodological review by Kaeppler and Mueller (2013), factors such as variation in similarity criteria and paradigms, choice of comparison class, potentially subjective selection of labels by the experimenters, and personal associations are all relevant factors in studies on olfactory cognition that rely on linguistic evidence.…”