> Hypothetical tetrachromacy has been demonstrated, that is, M and L cones with minor differences in peak spectral response existing in a retinal mosaic. The question arises whether this difference is capable of being propagated through the bipolar connecting neuronal paths (which form the "blue-yellow" and "red-green" channel paths conveying color info to the brain visual cortex).
Adding genes for extra cone types into normally dichromatic mammals (mice or something? I don’t remember off hand and I don’t have the citation at my fingertips) has seemed in studies to result in trichromatic vision, so it’s not too big a leap to suspect that tetrachromacy of the type described in the article might happen for some humans.
As you say there hasn’t been any study which showed this conclusively (that I’ve seen anyhow). I’d love to see more thorough research on these subjects who supposedly possess such vision.
> In art, there are great colorists and those who are virtually incapable of subtle use of color. If anyone interested in finding out about their own abilities, check out:http://www.xrite.com/online-color-test-challenge
Note, this online test is a bit easier than the paper version of the Farnsworth–Munsell hue test, since the colors in the screen version end up with some lightness differences that make it a bit easier to keep some sections of the chart in order. Either way, the test IMO mostly measures (a) whether someone has “normal” trichromatic vision, and (b) how patient and willing to fiddle with fine details they are. I don’t personally think Farnsworth–Munsell test scores are super meaningful, though a very poor score does indicate some color vision deficiency. [FWIW, if I take the time to do the test slowly, either on screen or on paper, I consistently score ~0, occasionally mixing up one pair or another.]
But anyway, I think the ability to be a good colorist in art has a whole lot to do with practice. Spending a lot of time mixing paint or color correcting photographs is likely to heighten awareness of tiny distinctions. For instance, I know that after a couple years of photography courses, several of my friends got much better at noticing color casts in photographs. Not that they couldn’t physically see them before, but after experience they more often spontaneously noticed the casts and started to have a feel for just how much adjustment in which direction would be necessary to counteract them.
\tangent A computer-based color test might not be able to detect tetrachromacy, because monitors do not display a continuum of frequencies of light. They are intrinsically tied to trichromacy, by combining only three frequencies of light in different proportions. RGB.
It's mathematically possible that a continuous spectrum of light also wouldn't pick it up, if its only effect was that different combinations of frequency that appear identical to an ordinary person could be distinguished. (Not that this would confer any evolutionary advantage.)
I got 39. I found the test interesting in terms of sorting algorithms. Typically when we think of sorting stuff, the comparison function is deterministic and cheap.
In this case, it gets increasingly hard and even erratic to tell adjacent colors apart; essentially the comparison function is increasingly expensive and non-deterministic.
I wonder if that has any consequences for the "optimal" strategy. In my case -- and I suspect most people did it the same way --, I used a kind of two-way insertion sort: for each field, I first decided if it should move left or right, then moved it as far as it "made sense". So I ended up with a list that got sorted from the outside towards the inside. In the end I had a few passes of "bubble sort", checking adjacent pairs for correctness. This was when it got expensive and erratic. :)
It would be a fun experiment to have an algorithm sort the list (based on whatever sorting algorithm) and simply use the human as a comparison robot: display two hues at the same time and let the human decide which of the two is "smaller". I'm sure you could easily measure and even predict the increase in "expense" (i.e. response time) and the increase in errors and ambiguity for close hues.
You could also do stuff like force the user to decide within a very short time, to determine if there's actually an increase in accuracy when staring at a given pair for 10 seconds vs a 500ms "hunch" decision (or heck, 10 500ms hunches, still a two-fold improvement).
> I think some of this has to do with practice. Spending a lot of time mixing paint or color correcting photographs is likely to heighten awareness of tiny distinctions.
I wouldn't doubt that practice could help, but the test (I believe) was designed to minimize practice effect. I've mixed a lot of color, but one can mix color to a shade only as far as one could determine it's right.
It used to be, color matching for printed material was done in large shops by workers visually comparing swatches to customer desired shades. This required training, but not every trainee could master it despite extra effort and time. Seemed it required native ability, talent as it were, to be able to be good at it.
Anyway, the online test is solely for one's own interest and information. I don't see there's anything substantial at stake.
I scored 0 on the test first time (perfect color vision), no practice, and I have pretty much no experience with any kind of art. (27 male for ref)
EDIT: Had another 2 tries, got 4 and 12. Turns out practice does more harm than good - after 3 tries it's a bit disorienting trying to read off the screen. Gonna have to take a break from machine.
I'm not sure how to describe it, I got 25... I could see the variances, in the tiles that looked "off" but wasn't always sure which direction to split to... I finally got frustrated and hit score. :-(
This would probably be a very large factor in the score. I scored a 7 on a calibrated Dell UltraSharp (IPS) monitor at work. If I were to do this same test on my cheap uncalibrated Acer at home, I don't believe my score would be nearly as good. Even the difference between a calibrated and an uncalibrated cheaper LCD should be noticeable to most people.
> I think some of this has to do with practice. Spending a lot of time mixing paint or color correcting photographs is likely to heighten awareness of tiny distinctions.
I've never done either, score 12, age +- 50, male.
Interesting test, harder than I thought it would be.
Adding genes for extra cone types into normally dichromatic mammals (mice or something? I don’t remember off hand and I don’t have the citation at my fingertips) has seemed in studies to result in trichromatic vision, so it’s not too big a leap to suspect that tetrachromacy of the type described in the article might happen for some humans.
As you say there hasn’t been any study which showed this conclusively (that I’ve seen anyhow). I’d love to see more thorough research on these subjects who supposedly possess such vision.
> In art, there are great colorists and those who are virtually incapable of subtle use of color. If anyone interested in finding out about their own abilities, check out: http://www.xrite.com/online-color-test-challenge
Note, this online test is a bit easier than the paper version of the Farnsworth–Munsell hue test, since the colors in the screen version end up with some lightness differences that make it a bit easier to keep some sections of the chart in order. Either way, the test IMO mostly measures (a) whether someone has “normal” trichromatic vision, and (b) how patient and willing to fiddle with fine details they are. I don’t personally think Farnsworth–Munsell test scores are super meaningful, though a very poor score does indicate some color vision deficiency. [FWIW, if I take the time to do the test slowly, either on screen or on paper, I consistently score ~0, occasionally mixing up one pair or another.]
But anyway, I think the ability to be a good colorist in art has a whole lot to do with practice. Spending a lot of time mixing paint or color correcting photographs is likely to heighten awareness of tiny distinctions. For instance, I know that after a couple years of photography courses, several of my friends got much better at noticing color casts in photographs. Not that they couldn’t physically see them before, but after experience they more often spontaneously noticed the casts and started to have a feel for just how much adjustment in which direction would be necessary to counteract them.