Grapheme–color synesthesia

[5] However, one recent study has documented a case of synesthesia in which synesthetic associations could be traced back to colored refrigerator magnets.

[2] Furthermore, the area of the brain where word, letter and color processing are located, V4a, is where the most significant difference in make-up was found.

[1] Writer and synesthete Patricia Lynne Duffy remembers one early experience: "'One day,' I said to my father, 'I realized that to make an 'R' all I had to do was first write a 'P' and then draw a line down from its loop.

'"[9]As does filmmaker Stephanie Morgenstern: "A few years ago, I mentioned to a friend that I remembered phone numbers by their colour.

I hadn't heard of synesthesia (which means something close to 'sense-fusion') – I only knew that numbers seemed naturally to have colours: five is blue, two is green, three is red… And music has colours too: the key of C# minor is a sharp, tangy yellow, F major is a warm brown..."[10]Many synesthetes never realize that their experiences are in any way unusual or exceptional.

For example, the Nobel Prize winning physicist, Richard Feynman reports: When I see equations, I see the letters in colors – I don't know why.

As I'm talking, I see vague pictures of Bessel functions from Jahnke and Emde's book, with light-tan j's, slightly violet-bluish n's, and dark brown x's flying around.

Here's a Thai chef who wrote a terrific vegetarian cookbook [these letters appear in a distinct pattern for Cassidy]:

This is especially problematic at parties.These experiences have led to the development of technologies intended to improve the retention and memory of graphemes by individuals without synesthesia.

[15] A somewhat related example of "computer-aided synesthesia" is using letter coloring in a web browser to prevent IDN homograph attacks.