Christelle Chrea

Mapping the Semantic Space for the Subjective Experience of Emotional Responses to Odors

Two studies were conducted to examine the nature of the verbal labels that describe emotional effects elicited by odors. In Study 1, a list of terms selected for their relevance to describe affective feelings induced by odors was assessed while participants were exposed to a set of odorant samples. The data were submitted to a series of exploratory factor analyses to 1) reduce the set of variables to a smaller set of summary scales and 2) get a preliminary sense of the differentiation of affective feelings elicited by odors. The goal of Study 2 was to replicate the findings of Study 1 with a larger sample of odorant samples and participants and to validate the preliminary model obtained in Study 1 by using confirmatory factor analysis. Overall, the findings point to a structure of affective responses to odors that differs from the classical taxonomies of emotion such as posited by discrete or bidimensional emotion theories. These findings suggest that the subjective affective experiences or feelings induced by odors are structured around a small group of dimensions that reflect the role of olfaction in well-being, social interaction, danger prevention, arousal or relaxation sensations, and conscious recollection of emotional memories.

Emotional Processing of Odors: Evidence for a Nonlinear Relation between Pleasantness and Familiarity Evaluations

Pleasantness, familiarity, and intensity are 3 interdependent dimensions commonly used to describe the perceived qualities of an odor. In particular, many empirical studies have demonstrated a positive correlation between familiarity and pleasantness. However, on the basis of both theoretical and methodological perspectives, we questioned the validity of such a relation for malodors. We report 2 studies based on subjective judgments of a large sample of odorants (Experiment 1) associated with autonomic recordings (Experiment 2). Multivariate exploratory analysis performed on the data splits the whole odorant set into 2 subsets composed, respectively, of unpleasant and pleasant odorants. Subsequent correlation analyses have shown that the relation between pleasantness and familiarity is specific for the pleasant odors in the 2 experiments. Moreover, autonomic activity was more important in response to malodors than to pleasant odors and was significantly correlated with unpleasantness ratings in the subset of unpleasant odors. These 2 studies argue in favor of a functional dissociation in the relations between both subjective and autonomic responses to odors as a function of pleasantness and indicate that researchers in the olfactory domain should consider the relations between pleasantness and familiarity as more complex than linear.

Taste-odour interactions in sweet taste perception

The sense of smell plays a major role in food flavour perception: Individuals who loose their sense of smell often report that food has no taste anymore. Yet, from a neuroanatomical point of view taste and smell are very different senses. Taste is perceived primarily on the tongue whereas odours are perceived in the upper part of the nasal cavity either directly or via the back of the mouth. But does this neuroanatomical dissociation imply that taste and odour perception are independent? Probably not! Indeed, information coming from the gustatory and the olfactory systems are likely to be combined at a higher level of processing in the brain to give rise to a unique perception referred to as ”flavour” (1), (28). The question thus is: What is the nature of this combination? Is it an additive combination whereby taste and odour perception are simply added to form an overall perception or can we observe interactions between taste and odours? In this context, taste odour interaction refers to a modification in perceived taste intensity in the presence of an odour. For example, a sweet solution will taste sweeter in the presence of a vanilla aroma even though the vanilla aroma possesses no taste properties. The aim of this chapter is to examine whether such interactions exist for sweet taste perception. We begin with an overview of the literature on the effect of odour

How to map the affective semantic space of scents.

The investigation of the semantic space associated with subjective affective experiences or feelings linked to odour perception has recently emerged. Because of the specificity of the emotional effects of odours, the terms derived from traditional models of emotion are unlikely to optimally account for odour-associated feelings. In this study, sets of terms derived from two traditional models, basic emotions and valence by arousal by dominance dimensional emotions, were compared with a recently elaborated olfaction-specific set of terms (Geneva Emotion and Odour Scale; GEOS). Three main criteria were considered: (1) the feelings intensity reported in response to odours; (2) the inter-rater agreement concerning the reported feelings; and (3) the power to discriminate feelings evoked by various odorous substances. The evidence strongly suggested that the set of terms proposed by GEOS outperformed the terms derived from the two classical models in measuring the subjective affective experience elicited by odours. These results are interpreted with respect to a good correspondence between the functions of olfaction and the meaning conveyed by GEOS terms.

Graded structure in odour categories: a cross-cultural case study.

The existence of graded structure in fruit and flower odour categories and its stability in different cultures is examined. Groups of students from France, the United States, and Vietnam performed a typicality rating task, a similarity judgment task, a membership verification task, a recognition memory task, a familiarity rating task, and a free identification task using a set of 40 odorants (20 fruit odorants and 20 flower odorants). Overall, our results demonstrate that fruit and flower odour categories possess graded structure. Moreover, principal component analyses of the data revealed the implication of typicality in a variety of cognitive tasks where typical odours receive a preferential processing compared to atypical ones. Finally, our results suggest that typicality can be predicted to a certain extent by experiential knowledge but that other determinants play a role in odour category structure. Altogether, this study confirms that graded structure is a universal property of categories and suggests that universals and cultural specifics can both constrain the emergence of odour category structures.