Seeing colours: I am a synesthete

Synesthesia is a neurological condition wherein one associates abstract, intangible things such as numbers, letters, words, musical notes or chords with sensory information usually associated with something physical, like colours, tastes or physical sensations. The most common form of synesthesia is grapheme-colour synesthesia. In this condition, one associates numbers, letters or words with colours. I have this condition. I've always had it. I assumed it was normal. I thought everyone saw colours when they thought of numbers, letters and words.

Wikipedia's page on synesthesia is fairly in-depth. There's also a website called the Synesthesia Battery which has an online test you can take to determine if you're synesthetic or not. (I took the test, and its results weren't as conclusive as I'd hoped for my own experiences. I feel that the test relies more on the user being able to repeatedly recognise fairly similar colours with very little margin for error than actually acknowledging when two quite similar colours are selected. I'm sorry, my brain doesn't function in HSV values.)

Whack the link below to keep reading, if you're into numbers and colours, and the unnatural marriage thereof.

Brady Haran's Numberphile, one of my favourite YouTube channels, recently posted a follow-up to their previous video on the subject of synesthesia. I've embedded both episodes below for your perusal:

And the follow-up:

I notice that these videos tend to avoid the subject of grapheme-colour synesthesia for letters and words, but I suspect there's a conscious decision at play considering the YouTube channel hosting them is dedicated largely to numbers.

I've included my own synesthesia alphabet above, for fun. It seems to me that my perception of grapheme-colour tends to be related largely to the geometric shape of the characters, with the following specifics:

• sharp angles seem to tend towards green and olive
• right angles lean towards brown, with "F" and "T" being very specifically brown. "L" strikes me as green, though
• Rounded shapes tend to take on a yellow hue
• "A", as recounted by many synesthetes, is almost always represented as red
• The three middle vowels are very neutral

My perception of numbers is more interesting:

There's less consistency, here. But, surprisingly, there's actually some logic, and much like Alex in the Numberphile videos, it seems to be largely factorial.

• One and zero are neutral, much like the vowels in the alphabet
• I have a suspicion that four is red largely because of its resemblance in form to the letter "A". If this is the case, my own mental association made this connection many years before Leetspeak was ever a thing
• A similar thing no doubt applies to five and its resemblance to "S"

The factorial nonsense comes into play when you organise the numbers:

Two, four and eight are warm coloured numbers.

Three, six and nine are cool.

I've found limited practical applications for my "abilities". One of the few is that in data entry work, I find that I can error-check data fairly efficiently by relying on the colours associated with figures. If a figure is supposed to be the same in two different locations, it's plainly obvious to me if it's not the right "colour".

Larger numbers are generally a gestalt of the colours represented by the figures that comprise them, with the hues blending across the figure. Some specific really big numbers have weird habits: One million (1,000,000) appears blue, presumably due to the connection with the letter "M", and one billion (1,000,000,000) appears green, again because of the letter "B".

Musical notes and chords also have coloured connections for me, again largely governed by the letters that associate with them.

When notes become flat or sharp, they change their appearance slightly. Flat notes (or chords) become darker. E flat actually becomes darker than its default state, black, but I can't represent this in a picture because there's nothing darker than black! Sharp notes and chords take on a desaturated look, with an ethereal kind of rusted vomit colour that I've been unable to represent graphically. (Come to think of it, I'm appalled by my description of it, too. Rusted vomit? Nice.)

Minor chords reflect a paler, ice-cream texture. Other chord types, 7ths, augmented chords, diminished chords, etc, have their own peculiar qualities.

I find it exciting to think about the possibility that synesthesia may be the only quantifiable example of qualia at work. Qualia is a collective term for all the little things that happen inside your mind, that you can't directly share with another person. For example:

• The age-old psychological litmus test: Do you see colours the same way I do? Is my red your blue? Does it matter?
• What does a strawberry taste like to you?
• What does a noise sound like to you?

Sensory information is fickle, and the idea that we all sense things the same way is largely untestable. The most frustrating (or perhaps relieving) thing about this problem is that it makes no difference in the end. If I see a stop sign as what I call "red", and you see it as what I call "blue" (but what you call "red"), it makes no difference, because we both call it "red" and stop at it.

Synesthetic responses could be the missing link for qualia. Many synesthetes report similar associations between colours and characters. Brady's second video (embedded above) includes a chart of reported synesthetic connections from his readers. It may be possible that this kind of information proves the existance, and uniqueness of qualia.

Oh, and Porcupine Tree have an awesome song from their 1992 album Up The Downstair entitled Synesthesia. You should go buy it from Burning Shed.