Very interesting, Ruby. It's standard in the literature to say that imagined graphemes are more strongly associated with their colors than visually presented ones. The main reason is that there's an interference effect with visually presented colors when the actual color and the synaesthetic color fail to match. I suppose it's possible to have the effect only for imagined graphemes, but I don't know of cases like that discussed in the literature.
I'm interested to see how DS does on the task. I did notice that this morning he looked very deliberately at the digital clock display and saw the number 40 in bright yellow lights, before reporting that 40 is gray.
BB
