The nature and origins of crossmodal associations to astringent solutions and basic tastes

People match gustatory (basic tastes) and non-gustatory stimuli (e.g., colors, shapes, and textures) to each other in a reliable manner. Yet, whether other attributes of the experience of flavor, such as, for example, astringency also evidence such reliable crossmodal mappings is currently unknown. Therefore, the aim of this study was to assess whether individuals make reliable crossmodal mappings between astringent solutions and non-gustatory stimuli (e.g., colors, shapes, hand-felt roughness/smoothness), and to examine the basis of any mappings observed. Participants sampled 6 solutions – astringent and 5 basic tastants – at 2 concentrations each (low, high), and for each selected their best matching color, texture, and shape (in three separate counterbalanced blocks). After making their selections, the participants evaluated the valence of the solutions, their colors, textures, and shapes, as well as the qualities/intensities of the solutions, and their confidence in the matches they made. Participants reported the rationale for their color-, texture- and shape matches at the end of the study. Color, texture, and shape selections evidenced consensual mappings, and participants were generally confident in all matches to a comparable level. Whilst people typically reported that their color matches were driven by real world associations (e.g., yellow chosen for sour, as lemons are yellow and sour), followed by valence (liking; e.g., pink for sweet, as both are liked), texture and shape matches to solutions were more attributable to intensity (e.g., rougher textures, selected for rougher feeling [e.g., astringent] solutions) as well as valence. Implications for flavor binding and marketing are discussed.