RE: Color perception arbitrary?
July 25, 2013 at 7:03 pm
(This post was last modified: July 25, 2013 at 7:28 pm by Anomalocaris.)
(July 25, 2013 at 6:53 pm)Napoléon Wrote: The names are arbitrary but the colours themselves aren't. Why is white, white? I'm not talking about labels, I'm talking specifically about the colour. Alternatively why do we have only 3 colour receptors as you say? Why not 4? Would we perceive new colours if that were so? Are there more colours to what we can see now? For that matter can you imagine a new colour? How come we only perceive the colours in our imagination that we can see with our eyes?
Mind fuck.
I try to address two separate questions:
1. Why not 4? Because of our evolutionary history.
Our distant precambrain evolutionary ancesters did in fact have four, (3 usually in wavelengths visible to us, and one extra one sometimes sensitive to ultraviolet), and can perceive 4 separate primary colors and see the world in combinations of those 4 primary colors. This is the ancesteral condition of the biological lineage that culminated in us.
Unfortunately somewhere on the way to us our early direct mammalian ancesters lost the genes for two of the four receptors, so many mammals perceive the world in combinations of only two primary colors.
But fortunately for us, early primates somehow through mutation developed a new red color receptor, so most living primates have genes for three color receptors and perceive the world in a pallate consisting of combinations of three primary colors, including red.
Other mammals would not see red directly. Instead they would see red as combinations of two other primary colors.
So we have three color receptors. Two of which we inherited from precambrain ancesters, one of which we have our early monkey ancesters to thank for. We lost two other color receptors, I don't know whether we know exactly which of our direct ancesters we can blame that on.
2. Why do our eyes perceive the three primary color that they do, and not some others?
This question can't yet be answered in detail, only in outline, because genetic changes can in fact make each photo receptor drift in the color of its maximum sensitivity. So we are only loosely limited by genetics and biochemistry to our three primary colors, it is certainly possible biologically for our primary colors to be somewhat different. The answer in outline is our immediate ancesters in their environment experienced the most survival advantage, ie, see the things most clearly that they need to see in order to survive, with our set of three primary colors.
