New research shows consistency in synaesthetic experiences

A quirky psychological phenomenon known as “grapheme-color synaesthesia” describes individuals who experience vivid colors whenever they see, hear, or think of ordinary letters and digits. A hallmark of synaesthesia is that individuals seem to be idiosyncratic in their experiences. That is, most synesthaetes will consistently see the same colors accompanied with specific graphemes, but few of these experiences appear to be shared with other synesthetes.