September 19 : A new research at the University of Waterloo has found a particular commonality among people with psychological phenomenon called “grapheme-colour synaesthesia” in which vivid colours are experienced whenever they see, hear, or think of ordinary letters and digits.

A hallmark of synaesthesia is that individuals tend to be idiosyncratic in their experiences, though these experiences are consistent for synaesthetes throughout their lifetime, according to the background information in a report published in the journal Psychological Science.

Psychologist Daniel Smilek and his colleagues at the university have now found that a relationship exists between how frequently a synaesthete uses a given digit and the brightness of synaesthetic colour experiences.

He says that the more often letters or digits are used in everyday life, the more luminous the synaesthetic colours. The researcher claims that the relationship is not limited to synaesthetic colour experiences.

During the study, non-synaesthetes were asked to select a colour to associate with each letter of the alphabet and the digits 0-9. The researchers found that the study subjects also selected more luminous colours for digits and letters used more frequently.

Smilek has revealed that the relationship between letter and digit frequency and colour luminance was much weaker for non-synaesthetes than synaesthetes.

“The evidence suggests the possibility that the unusually strong grapheme-colour associations made naturally in synaesthesia may more closely reflect normal cognitive processes than previously thought,” he says. (ANI)