Anne-Sylvie Crisinel

Crossmodal correspondences between odors and contingent features: odors, musical notes, and geometrical shapes

Olfactory experiences represent a domain that is particularly rich in crossmodal associations. Whereas associations between odors and tastes, or other properties of their typical sources such as color or temperature, can be straightforwardly explained by associative learning, other matchings are much harder to explain in these terms, yet surprisingly are shared across individuals: The majority of people, for instance, associate certain odors and auditory features, such as pitch (Belkin, Martin, Kemp, & Gilbert, Psychological Science 8:340–342, 1997; Crisinel & Spence, Chemical Senses 37:151–158, 2012b) or geometrical shapes (Hanson-Vaux, Crisinel, & Spence, Chemical Senses 38:161–166, 2013; Seo, Arshamian, et al., Neuroscience Letters 478:175–178, 2010). If certain odors might indeed have been encountered while listening to certain pieces of music or seeing certain geometrical shapes, these encounters are very unlikely to have been statistically more relevant than others; for this reason, associative learning from regular exposure is ruled out, and thus alternative explanations in terms of metaphorical mappings are usually defended. Here we argue that these associations are not primarily conceptual or linguistic, but are grounded in structural perceptual or neurological determinants. These cases of crossmodal correspondences established between contingent environmental features can be explained as amodal, indirect, and transitive mappings across modalities. Surprising associations between odors and contingent sensory features can be investigated as genuine cases of crossmodal correspondences, akin to other widespread cases of functional correspondences that hold, for instance, between auditory and visual features, and can help reveal the structural determinants weighing on the acquisition of these crossmodal associations.

A Fruity Note: Crossmodal associations between odors and musical notes

Odors are notoriously difficult to describe, but they seem prone to a variety of crossmodal associations. In the present study, we generalize the previously-shown association between odors (from perfumery) and pitch (Belkin et al. 1997) to odors related to food and drink (in this case those associated with wine). We also demonstrate that, to a lesser extent (25% of the odor tested), participants preferentially match specific odors to certain types of instruments. The ratings of the odors along a number of dimensions are used in principal components analysis (PCA) to explore the psychological dimensions underlying the odor-pitch associations. The results demonstrate that both pleasantness and complexity, but not intensity, appear to play a role when choosing a pitch to match an odor. Our results suggest that these features of odor stimuli constitute psychological dimensions that can be consistently matched to auditory features.

Composing with cross-modal correspondences: Music and odors in concert

We report two experiments designed to investigate cross-modal correspondences between a range of seven olfactory stimuli and both the pitch and instrument class of sounds as well as the angularity of visually presented shapes. The results revealed that odors were preferentially matched to musical features: For example, the odors of candied orange and iris flower were matched to significantly higher pitches than the odors of musk and roasted coffee. Meanwhile, the odor of crème brûlée was associated with a more rounded shape than the musk odor. Moreover, by simultaneously testing cross-modal correspondences between olfactory stimuli and matches in two other modalities, we were able to compare the ratings associated with each correspondence. Stimuli judged as happier, more pleasant, and sweeter tended to be associated to both higher pitch and a more rounded shape, whereas other ratings seemed to be more specifically correlated with the choice of either pitch or shape. Odors rated as more arousing tended to be associated with the angular shape, but not with a particular pitch; odors judged as brighter were associated with higher pitch and, to a lesser extent, rounder shapes. In a follow-up experiment, we investigated whether people could match specific pieces of music (composed to represent odors) to three of the odors (candied orange, crème brûlée, and ginger cookies). In one case (candied orange), a majority of the participants matched the odor to the intended piece of music. In another case (ginger cookies), another piece of music (than the one intended) was preferred. Finally, in the third case (crème brûlée), people showed no preference in matching the odor to the pieces of music. Both theoretical and practical implications of these results are discussed.

Crossmodal associations between flavoured milk solutions and musical notes.

A number of crossmodal associations have now been described in the context of food evaluation, such as between tastes or flavours and musical notes (Crisinel & Spence, 2010b). Here we extend these findings by presenting flavoured milk solutions of varying fat contents. The participants in the present study matched a series of milk samples to musical notes. They chose both the pitch and the class of instrument that they felt was most appropriate for each sample. Participants also rated various features of the samples, such as their pleasantness, bitterness, or familiarity. Consistent associations between flavours and both pitch and instruments were confirmed. However, fat content did not influence either the pitch or instrument chosen, although it did have an effect on pleasantness and intensity ratings. These results demonstrate that flavour-sound associations are not restricted to basic tastes and flavours presented individually, but are still present in the context of more complex food stimuli. The present study opens the way for further investigations into the nature and characteristics of crossmodal associations (or correspondences) between more complex stimuli, both in the auditory and gustatory/olfactory modalities. This novel approach could lead to new insights into the representation of chemosensory stimuli in humans.

‘The Sweet Taste of Maluma’: Crossmodal Associations Between Tastes and Words

Several recent studies have demonstrated the existence of crossmodal associations (or correspondences) between tastes and non-words, such as ‘maluma’ and ‘takete’. In the present study, we further explore these associations, using tastes and flavors solutions. Participants rated the stimuli on scales anchored by either non-words, taste descriptors, or other descriptors. The results confirm the existence of consistent crossmodal associations between tastes/flavors and words. Moreover, the results of principal components analysis suggest that these associations are likely based on the evaluation of the ‘hedonic value’ and ‘activity’ of the stimuli, two of the three dimensions first identified by Osgood (Psychol Bull 49:197–237, 1952), and since then repeatedly documented in the evaluation of a variety of sensory stimuli. The crossmodal associations elicited by non-words are particularly relevant for the naming/labelling of food products, since they might elicit expectations prior to consumption (and hence potentially be used to avoid any disconfirmation of expectation).

Crossmodal correspondences between chemosensory stimuli and musical notes

We report a series of experiments investigating crossmodal correspondences between various food-related stimuli (water-based solutions, milk-based flavoured solutions, crisps, chocolate and odours) and sounds varying in pitch and played by four different types of musical instruments. Participants tasted or smelled stimuli before matching them to a musical note. Our results demonstrate that participants preferentially match certain stimuli to specific pitches and instrument types. Through participants’ ratings of the stimuli along a number of dimensions (e.g., pleasantness, complexity, familiarity or sweetness), we explore the psychological dimensions involved in these crossmodal correspondences, using principal components analysis (PCA). While pleasantness seems to play an important role in the choice of instrument associated with chemosensory stimuli, the pitch seems to also depend on the quality of the taste (bitter, salty, sour or sweet). The level at which such crossmodal correspondences might occur, as well as the potential applications of such results, will be discussed.