Why Does Evolution Allow Some People to Hear Colors?

National Geographic has a piece on the evolution of synesthesia, which is broadly defined as “a neurologically based condition in which stimulation of one sensory or cognitive pathway leads to automatic, involuntary experiences in a second sensory or cognitive pathway.” In the most extreme cases, this means that people can taste words or hear colors.

This article caught my eye because I realized a number of years ago that I have a mild case of grapheme color synesthsia. I basically associate a color with every letter and number. The colors don’t change, and there doesn’t seem to be a logical reason as to why each letter or number has its color. For example, 7 is green. M is red. I don’t see colors when I look at written text, but when I think about words or numbers (e.g., a phone number), each character has its respective color.

My case is so mild that I didn’t even realize this was unusual until about six years ago when I asked someone else whether the colors they associate with letters and numbers change over time and got a very confused response. I’ve since found a handful of people that have similar associations (if anyone from Sloan is reading this, Kanaka is one of them).

The article links synesthesia to creativity and artistic capability. Maybe that’s true for the types that can taste words, but I don’t think it helps me in any way. I suppose on occasion when I forget someone’s phone number I may remember that it starts out yellow. Unfortunately, both 4 and 8 are yellow.

Any readers out there have something similar going on?