Learning partial grapheme synaesthesia

Abstract

Synaesthesia is a variation of normal human perception. A grapheme synaesthete, for example, can experience extra sensations, such as colours when seeing letters and/or numbers. Synaesthetic ability is commonly developed at an early age, and is linked to a genetic pre-disposition; however, there is a learnt component, as one must also learn to read and write to develop grapheme synaesthesia. To explore the extent to which synaesthesia can be learnt, a training method was employed, which was first used by Colizoli, Murre and Rouw (2012). In order to learn their own coloured letters a group of non-synaesthetic individuals read colour books, which are free eBooks reproduced to have four letters consistently appear in colour. Before and after reading, the participants completed a modified Stroop-design based on Mills (1999), which was used to measure if they had learnt the two key characteristics of synaesthesia, namely an involuntary and automatic reaction to letters. Both the colour reading (n=15) and control (n=6) groups did not have a significant involuntary reaction to letters. However, it was found that the participants had significantly more automatic reactions to letters. This included the control group, who did not read in colour, which suggests that merely completing the modified Stroop test is enough to learn the automatic characteristic of grapheme synaesthesia.