There was a very interesting BBC reports about perception of colors. The eye is capable of separating millions of colors and captures the right information but the brain interprets it in a different way and make you see want it wants you to see. The topic was about illusions and 'magic' tricks designed to alter sense of reality. That's why it always makes chuckle when I hear people commenting too red, too green, etc.. in pictures when most of the time if you actually use the color picker in PS and put the color sampled on top of a white background it might turn orange or even blue.
