Interesting. I wonder if some people are primed to develop such strong associations among different sensory experiences that the pathways become so ingrained as to evoke the original (in this case color) experience in it's pure neurological/sensory form even it's not consciously remembered (i.e., it would result in a "lower" synesthesia). So maybe BDad's DS hasn't yet had the (unconscious) experience of the remaining numbers being associated with a color, that's why they haven't been "painted" yet. I always wondered why I always "saw" green when I thought about Tuesday, but other days of the week had no color.
