SynQuiz tests this 'grapheme-colour' synaesthesia. The first three short quizzes in the app are designed to give a taste of what synaesthesia might be like and to find out whether you might be ...
On the standard definition, synaesthesia is an condition in which people make 'unusual associations' between various 'sensations'. For example, a colour-grapheme synaesthete sees/thinks of letters ...
As editors Julia Simner and Edward M. Hubbard write in the introduction to the recently published Oxford Handbook of Synesthesia, there has probably never been a better time to write such a volume.