Word-gustatory synesthesia: a case study

A case study of a rare form of synesthesia is presented, where specific words act as the inducer, and gustatory sensations function as the concurrent. The female participant (TD) was twice presented with a list of 806 English words and 222 grammatically correct non-words (with 3 months between presentations). For each presentation, TD was asked to provide: a subjective description of the gustatory experience (if any) associated with each stimulus; a rating (from 0 to 10) of the intensity of the gustatory experience; and an indication (yes/no) if the experience was aversive. TD's responses across the two presentations were quantified, and comparisons are provided. In addition, TD's ability to create and recall novel word-taste associations was compared to that demonstrated by a sample of ten age-matched non-synesthete females. TD's synesthetic experiences were found to be highly consistent, more common in English words than non-words, and rarely aversive. Although TD was superior to control participants in remembering novel word-taste associations, her reported experiences cannot be wholly explained by either an exceptional non-synesthetic learning of taste-word associations over time, or a clear response to phonemes, rather than whole words. These conclusions are compared to the five other published reports of word-gustatory synesthesia, and directions for future research are discussed.