Your point is valid, and while I agree there is not strong enough evidence for a causal connection, I think the idea is interesting.
My mother has painted Impressionist-style oil paintings my whole life, and taught painting classes. In her classes, she always tells people to use colors that they don't see ("You need the pink on the water", etc). Once you've painted enough, you learn to realize what colors are in the scene but not quite obvious. You definitely exaggerate the colors ("hint of pink" becomes "pink streaks") while painting in this style, but it also forces you to think harder about what colors your eye actually sees.
So it seems to me that impressionist-style coloring can definitely come from "faking it" (being taught it, and trying hard), but I would definitely believe it could come from tetrachromism, where those small differences stick out to you a lot. It would be fascinating to know if any early impressionists had evidence of being tetrachromatic.
I agree with this. Often the colors are there, that edge is warm and that edge is cool, but sometimes a shape is just not very interesting, the color isn't interacting and your job as the artist is to make everything work. Through that process you learn to see color.
My mother has painted Impressionist-style oil paintings my whole life, and taught painting classes. In her classes, she always tells people to use colors that they don't see ("You need the pink on the water", etc). Once you've painted enough, you learn to realize what colors are in the scene but not quite obvious. You definitely exaggerate the colors ("hint of pink" becomes "pink streaks") while painting in this style, but it also forces you to think harder about what colors your eye actually sees.
So it seems to me that impressionist-style coloring can definitely come from "faking it" (being taught it, and trying hard), but I would definitely believe it could come from tetrachromism, where those small differences stick out to you a lot. It would be fascinating to know if any early impressionists had evidence of being tetrachromatic.