Sweet Is Soft, Bitter Is Rough: Evidence for a Shared Emotional Dimension Across Taste and Touch

Although taste and touch are processed through separate sensory channels, both elicit strong emotional responses that may share an underlying affective organization. This study investigated whether gustatory and tactile experiences are structured within a common emotional coordinate system defined by valence and arousal. To address this question, we re-analyzed two previously collected datasets, one for taste-based emotion ratings and one for tactile emotion ratings. In two independent datasets, 30 participants evaluated four taste stimuli (sweet, sour, bitter, and salty) on ten affective adjectives, while a separate group of 27 participants rated four tactile textures (rough-hard, rough-soft, smooth-hard, and smooth-soft) on twenty affective adjectives. Principal component analyses of the group-averaged emotion matrices revealed comparable two-dimensional affective spaces in both modalities, corresponding to pleasant-unpleasant and high-low arousal dimensions. Procrustes alignment and consensus mapping demonstrated strong geometric correspondence between taste and touch, with sweet aligning most closely with smooth-soft, sour with smooth-hard, salty with rough-hard, and bitter with rough-soft. Quantitatively, the Procrustes distance was low ( d = 0.094), the mean cosine similarity across pairs was 0.70, and the Mantel test showed a significant correlation ( r = 0.90, p = 0.04), confirming robust cross-modal affective similarity. A combined multidimensional scaling solution further integrated both modalities into a unified affective map with negligible stress. Together, these results provide converging evidence that affective responses to taste and touch follow a shared low-dimensional structure, supporting the idea that affective responses across modalities can be represented within a common evaluative coordinate space. This finding highlights emotion as a unifying representational framework that bridges distinct perceptual domains and informs multisensory theories of affect.