| Synesthesia is the phenomenon in which the stimulation of one sensory modality activates a response in another modality, for example, tasting colors or smelling words. One of the most common types of synesthesia is chromesthesia, in which individuals see sounds as colors. Past research has indicated that the general population has an attenuated form of chromesthesia, called pseudochromesthesia, in which there is an association between hue of color and pitch of sound, but no visual hallucination upon being played tones of different pitch. Specifically, studies have shown that individuals display a linear relationship between pitch and hue. Synesthetes who see colored sounds also display a linear relationship, but more consistently over time than non-synesthetes.;The author attempted to examine the relationship between hue and pitch in two groups---individuals who demonstrate a proneness to psychosis, and individuals who display very low proneness. The study is based on indications that psychotic individuals may display reliable synesthetic characteristics. The question investigated here is whether these synesthetic characteristics are a developmental feature in psychotically-prone individuals, or a symptom of psychosis. The author hypothesized that individuals who display high levels of magical ideation, perceptual aberration, and absorption into imaginative states would show a more linear relationship between color and tone, and that this relationship would be consistent over time. These relationships were measured by two tasks: in one, participants listened to six tones in random sequences, and chose a color they associated with each tone. In the other, they were asked to match 13 notes with colors on a computer, repeating the task three times.;In all, 30 individuals who were found to be highly prone to psychosis and 31 individuals who were not prone to psychosis were recruited. Their performance indicated no differences in the relationship between hue and pitch, nor consistency in that relationship over time. Both high and low-prone groups showed a cubic relationship between hue and pitch, with participants generally choosing shorter wavelength colors (blue, violet) for lower pitches, higher wavelength colors (orange, red) for moderate pitches, and middle wavelength colors (yellow) for high pitches. Highly prone individuals were more likely to choose shorter wavelength colors overall, which may be due to brightness or emotional valence behaviorally assigned to colors, but both groups showed consistency and the same level of variability on both color/tone tasks, suggesting no difference in synesthetic ability. Additionally, highly-prone individuals reported significantly higher overall drug use than low-prone individuals, and significantly higher subjective synesthetic experience, suggesting a difference between the perception of synesthesia and the objective phenomenon Implications for future research are discussed. |
