The example you linked to was "men with Klinefelter syndrome, who have two X chromosomes and one Y chromosome". I wrote "a man with (I presume) XY" because I d

The example you linked to was "men with Klinefelter syndrome, who have two X chromosomes and one Y chromosome". I wrote "a man with (I presume) XY" because I don't recall if the show I watched also described his chromosomes, but in order to be a reasonable control I don't see why they wouldn't have done so. (I can not find the video, and it's been too long for me to recall more details than I described.) Training certainly helps identify nuances in color. Color terms are also culturally dependent. https://en.wikipedia.org/wiki/Color_term#Cultural_differences https://en.wikipedia.org/wiki/Color_term#Cultural_difference... That said, there should be no reason to believe training will result in an ability to see like a tetrachromat through intensive training - the cones don't have a differentiating signal to train upon.