Having recently read Phantoms in the Brain, I’ve gotten around to wondering whether the division of the spectrum is unique to humans or even individuals.
In other words, does everyone “see the same color” when they look at light belonging to the ‘red’ portion of the spectrum. On a broader note, does the visible spectrum start and end at different points for different optical devices (human eye vs. dog eye vs. bat eye …etc)?
I’ve often wondered the same thing, and I’ve come to the conclusion that there’s not really any way to tell - and that it doesn’t really matter.
For it to matter, you would need a way for one person to “see” what is in another person’s mind. Telepathy isn’t that far yet (if it exists at all,) so the question is kind of moot.
I attended a lecture given by Dr Arthur Tarrant (http://colour.derby.ac.uk/colour/people/tarrant/) where he demonstrated that people do perceive colours differently from each other.
He did this by projecting a patch of colour through a filter and getting people to try to match that colour by mixing red, green and blue lightsources (controlled by analog dials). I remember the patch and the mixed area looking clearly different to me when someone else had matched them in their mind.
Having a look in the colour picker in Paint Shop Pro (and trying to remember what I saw at the time) I think the differences between people were, at maximum, around 5/255 (2%) in hue, and often less.
Perhaps that makes more sense as 7 degrees as the hue axis is circular.
There’s no way to tell whether red looks to me the same as what you would call green; perception happens in the brain, not the eyes, however, it is possible to tell that the sensors themselves (the rods and cones) are pretty much uniformly calibrated for individuals of the same species. There are people who have an extra type of cone cell, I believe, and this enables them to discern more shades of red than the average person.
I think it is also true that some animals have sensors that are differently tuned and so they would be sensitive to a different range of wavelengths, which may in various cases be broader or narrower than our own, but again, there is no way to tell what it actually looks like to them, that is until I perfect my mind-transfer machine.