COLORED SPEECH-PERCEPTION - IS SYNAESTHESIA WHAT HAPPENS WHEN MODULARITY BREAKS DOWN

Evidence was reported earlier from a single case that chromatic-lexica l (CL) synaesthesia was a genuine phenomenon. A study is presented in which nine subjects were tested who also reported having coloured hear ing. The following questions were addressed: (a) were these cases also genuine (ie consistent over time), (b) were they truly lexical, or ra ther variants of this condition, such as chromatic-graphemic (CG) or c hromatic-phonemic (CP) synaesthesia, (c) did the experimental subjects show any commonalities between them, and (d) were they able to give i nformation on a standard questionnaire about the phenomenology and ont ogenesis of the condition? Subjects were asked to describe the colour sensation experienced on hearing items from a list of 130 words, phras es, and letters. The experimental group were not informed of any retes t, but were retested more than one year later. A control group (n = 9) , matched for IQ, memory, age, and gender, were read the same list and asked to associate a colour with each list item. They were informed a t the time of testing that they would be retested on a sample of items from the list a week later. 92.3% of the responses of the experimenta l group when retested one year later were identical to those given in the original test, compared with only 37.6% of the control subjects' r esponses (retested one week later). This confirmed the genuineness of these nine cases. All nine experimental subjects showed CG synaesthesi a, none showing either CL or CP synaesthesia. Among the experimental g roup, some consistency was found in the colours evoked by hearing spec ific letters, suggesting the condition has a neurological basis. There was also evidence of a genetic sex-linked familial pattern underlying the condition. The importance of these distinct forms of synaesthesia for our understanding of the modularity of speech perception and colo ur vision is discussed.