Affective correspondences: According to the affective mediation account, people may simply want to match pairs of stimuli if they happen to evoke the same feeling or emotion or are known to be associated with the same affective state (e.g. [ 5, 39, 66, 68]). Relevant here is the longstanding literature showing that colours are associated with emotions [ 37, 38, 52]. Similarly, hedonic responses are also associated with/triggered by the presentation of basic tastes [ 3, 44, 47, 59]. Hence, given what is already known, the participants in the studies reported in the “ Crossmodal correspondences between colour and taste words: the empirical evidence” section could, presumably, potentially be matching based on the hedonic value or emotion associated with each individual stimulus. No one has, though, as least not as far as we are aware, proposed an affective mediation account specifically of the crossmodal correspondence between colours and basic tastes. That said, it is worth noting that the affective account has recently gained traction as a plausible explanation for the crossmodal correspondence between colours and both fragrances [ 48] and music [ 39]. Further investigation of the affective mediation account could presumably utilize a version of the clever experimentation introduced recently by Palmer et al. [ 39]. Footnote 16 Woods AT, Poliakoff E, Lloyd DM, Dijksterhuis GB, Thomas A. Flavor expectation: the effect of assuming homogeneity on drink perception. Chemosens Percept. 2010;3:174–81. Werning M, Fleischhauer J, Beseoglu H. The cognitive accessibility of synaesthetic metaphors. In: Proceedings of the Twenty-Eighth Annual Conference of the Cognitive Science Society. London, UK: Lawrence Erlbaum; 2006. p. 2365–70. Koriat A. Subjective confidence in one’s answers: the consensuality principle. J Exp Psychol Learn Mem Cogn. 2008;34:945–59.

Characterizing the relation between basic tastes and colour as a kind of crossmodal correspondence does not presuppose that a single relation is at stake. Although tastes are often described as being, in some sense, ‘basic’, they will also have a perceived intensity and an associated hedonic valence once in the mouth [ 3]. Likewise, colours are also analysed and described in terms of different dimensions, such as their hue, saturation, and brightness. In this respect, then, there might well be different correspondences, or even a complex network of correspondences, underlying the matching of any specific colour with any particular taste. So, for instance, one such mapping might exist between more intense tastes and more intense (i.e. brighter and more saturated) colours (see [ 54, 55]). Outline Simmons DR. Colour and emotion. In: Biggam CP, Hough CA, Kay CJ, Simmons DR, editors. New directions in colour studies. USA: John Benjamins Publishing Company; 2011. p. 395–413. Marks LE. On colored-hearing synesthesia: cross-modal translations of sensory dimensions. Psychol Bull. 1975;82:303–31. Cytowic RE, Wood FB. Synaesthesia II: psychophysical relations in the synaesthesia of geometrically shaped taste and colored hearing. Brain Cogn. 1982;1:36–49. Some case studies of chromatic gustation are very striking. For instance, the synaesthete “S”, who was thoroughly tested a little over a century ago by Downey [ 15] experienced very vivid colour concurrents that could last for up to 10 min. Footnote 10 These colour concurrents were localized to the mouth and tended to be stronger when S closed his eyes (see [ 15], p. 528) . Downey carefully controlled stimulus delivery so we can be certain that it really was the tastes (in the gustatory sense) of the stimuli that were the inducer in this case. Footnote 11 Another interesting finding was that while colour concurrents were triggered by pure tastants, they were not elicited by food-related odours. Footnote 12No added sugar: Each bottle of original Fruit Shoot contains about half teaspoon of sugar only; never containing added sugars, fruit shoot is sweetened from the sugars naturally occuring in real fruit juice resulting in a refreshing, low calorie drink Spence C, Deroy O. Tasting shapes: a review of four hypotheses. Theoria et Historia Scientiarum. 2013;10:207–38. Shermer DZ, Levitan CA. Red hot: the crossmodal effect of color intensity on piquancy. Multisensory Res. 2014;27:207–23. The oaky wine flavor of the brandy is perfectly balanced by the herbal flavor of the Green Chartreuse, and the acidic citrus is cut perfectly by the syrup. It tastes like an herbal brandy sour, but its proportions make it balanced and tasty. If you have never had this, you don’t know what you are missing—one of the top 5 drinks I have ever had. The Most Important Ingredient Collier GL. Affective synaesthesia: extracting emotion space from simple perceptual stimuli. Motivation and Emotion. 1996;20:1–32.

Walker P. Cross-sensory correspondences and cross talk between dimensions of connotative meaning: visual angularity is hard, high-pitched, and bright. Atten Percept Psychophys. 2012;74:1792–809.Palmer SE, Schloss KB, Xu Z, Prado-León LR. Music-color associations are mediated by emotion. Proc Nat Acad Sci USA. 2013;110:8836–41. The existence of chromatic gustation synaesthesia and, more generally, the unusual experiences reported by representatives of the roughly 4 % of the population who count as synaesthetes have often been used as inspiration in the fields of art and design (e.g. [ 23]). Here, though, we wish to argue that the idiosyncratic nature of the synaesthete’s concurrents (this, in fact, being a defining feature of the condition, at least according to some researchers; see [ 21]) means that it is going to be exceedingly difficult to take the concurrent colours that are experienced by a chromatic gustation synaesthete as a useful source of information when it comes to trying to generate specific expectations of taste based on colour that work with the public at large. That said, it should not come as any surprise if it turns out that certain of the taste inducer-colour concurrent mappings reported in those synaesthetes with chromatic gustation end-up matching, at least in a subset of cases, the taste-colour correspondences reported by non-synaesthetes: S, for instance, reported seeing green on being given a sour taste [ 15]. After all, the combination of 10 colours and 5 basic tastes is not so large that some synaesthetes will not present one of the 6–8 associations found in non-synaesthetes by chance. It would also not be all that surprising if (in fact, one might expect that) the matchings learned by individual synaesthetes are constrained by the highly regular correspondences that are present in every one of us (see [ 14]). Where do crossmodal correspondences between colour and taste come from? Velasco C, Woods A, Deroy O, Spence C. Hedonic mediation of the crossmodal correspondence between taste and shape. Food Qual Prefer. 2015;41:151–8. In 2008, Tomasik-Krótki and Strojny had their participants (a convenience sample of more than 500 individuals from 17 different countries, covering a number of continents) via questionnaire: “how they link the colours, red, orange, yellow, green, blue, and violet to the tastes bitter, sweet, umami, sour and salty” ([ 65], p. 253). The wording of the article itself is a little ambiguous as to what exactly the participants had to do. Footnote 4 That said, crossmodal associations between red and orange with sweet, yellow and green with sour, blue with salty, and violet with bitter and umami were documented (see Table 2). A subset of the participants in this study also associated a bitter taste with the colour green. The researchers’ interest in carrying out this study was different again from that in the other previous studies reported in this section. Tomasik-Krótki and Strojny were specifically interested in trying to establish any crossmodal associations between colours and both tastes and odours on the other. These researchers created units of taste (mnians) and odour (fooys) and a permutation system that would allow for the standardized translation of one sensory impression into another across the senses.

Day S. Some demographic and socio-cultural aspects of synesthesia. In: Robertson LC, Sagiv N, editors. Synesthesia: perspectives from cognitive neuroscience. New York, NY: Oxford University Press; 2005. p. 11–33.

Schifferstein HNJ, Tanudjaja I. Visualizing fragrances through colors: the mediating role of emotions. Perception. 2004;33:1249–66. Finally, it is perhaps worth noting that, at least as far as we are aware, no one has offered a structural account of the correspondence between colour and basic taste. The same is not true of the relation between brightness and intensity of taste, which might, presumably, be explained by a common coding of stimulus intensity. Utilizing the crossmodal correspondence between colour and taste Fruit Drink – This legendary fruit drink is a great replacement for energy drinks, formulated with fruits & botanical flavours, this fruit drink is sure to keep you hydrated and energized all day long, a perfect immune system booster. Borges JL, Bioy-Casares A. An abstract art. In: Golden L, editor. A literary feast. New York, NY: The Atlantic Monthly Press; 1993. p. 70–3. Demattè ML, Sanabria D, Spence C. Cross-modal associations between odors and colors. Chem Senses. 2006;31:531–8.