An investigation of the cognitive and perceptual dynamics of a colour-digit synaesthete.

L, a 47-year-old female of Choctaw descent, was first identified as a potential synaesthetic++ on the basis of self-report data regarding digit-colour associations. Upon completion of the identification procedures typified in the literature, it was concluded that L met the classic memory-performance criteria used to identify synaesthetic ability. A series of Stroop-type tasks were then performed to identify the dynamics of her synaesthetic experiences. The results of these analyses provided three findings of note. First, the clear pattern of response-time differences between L and the control group suggests that tasks designed to produce involuntary divisions of attention can be an effective means by which to demonstrate that synaesthetic experiences are involuntary but elicited. Second, the significantly slower performance by L on a negative-priming Stroop list shaped around her colour-digit associations indicates the presence of a lexical component in her synaesthetic experience. Third, the use of a manual colour-classification task for which a verbal response was not employed served to confirm the presence of a lexical component in L's synaesthetic experiences. The implications of these results for current synaesthetic theories are then discussed. Finally, a clustering solution of a portion of L's colour-digit experiences is presented, along with the ramifications of its results on the nature of L's perceptual experience.