#NeuroThursday is back this week to talk about the #neuroscience of #synesthesia. What does it mean for a letter to have an intrinsic color, for a number to have a distance? And why the heck would this trait evolve in humankind?
Synesthesia is when "stimulation of one sense automatically provokes a secondary perception in another." The secondary perception can be direct ("9's are red") or associative ("9's make me think of red"), either counts.
Synesthesia comes in countless forms, but color-based are the most frequent. The most well-known is "grapheme-color" synesthesia, where a grapheme (written shape, e.g. letter or numeral) has a color - like the opening picture.