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Tue Jun 19, 2012, 03:35 PM

The Humans With Super Human Vision

An unknown number of women may perceive 
millions of colors invisible to the rest of us. One British scientist is trying to track them down and understand their extraordinary power of sight.
by Veronique Greenwood

An average human, utterly unremarkable in every way, can 
perceive a million different colors. Vermilion, puce, cerulean, periwinkle, chartreuse—we have thousands of words for them, but mere language can never capture our extraordinary range of hues. Our powers of color vision derive from cells in our eyes called cones, three types in all, each triggered by different wavelengths of light. Every moment our eyes are open, those three flavors of cone fire off messages to the brain. The brain then combines the signals to produce the sensation we call color.

Vision is complex, but the calculus of color is strangely simple: Each cone confers the ability to distinguish around a hundred shades, so the total number of combinations is at least 1003, or a million. Take one cone away—go from being what scientists call a trichromat to a dichromat—and the number of possible combinations drops a factor of 100, to 10,000. Almost all other mammals, including dogs and New World monkeys, are dichromats. The richness of the world we see is rivaled only by that of birds and some insects, which also perceive the ultraviolet part of the spectrum.

Researchers suspect, though, that some people see even more. Living among us are people with four cones, who might experience a range of colors invisible to the rest. It’s possible these so-called tetrachromats see a hundred million colors, with each familiar hue fracturing into a hundred more subtle shades for which there are no names, no paint swatches. And because perceiving color is a personal experience, they would have no way of knowing they see far beyond what we consider the limits of human vision.

more

http://discovermagazine.com/2012/jul-aug/06-humans-with-super-human-vision

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Arrow 32 replies Author Time Post
Reply The Humans With Super Human Vision (Original post)
n2doc Jun 2012 OP
gordianot Jun 2012 #1
Swede Jun 2012 #2
Confusious Jul 2012 #25
6502 Jul 2012 #29
Silent3 Jun 2012 #3
AnotherMcIntosh Jun 2012 #4
laconicsax Jun 2012 #6
Posteritatis Jun 2012 #19
Geoff R. Casavant Jun 2012 #5
laconicsax Jun 2012 #7
Silent3 Jun 2012 #10
Spitfire of ATJ Jun 2012 #16
laconicsax Jun 2012 #17
Spitfire of ATJ Jun 2012 #18
HopeHoops Jul 2012 #31
chknltl Jul 2012 #26
PADemD Jun 2012 #8
Bradical79 Jun 2012 #13
knitter4democracy Jun 2012 #14
Marrah_G Jun 2012 #15
laconicsax Jun 2012 #21
NickB79 Jun 2012 #23
Nay Jul 2012 #27
Ganja Ninja Jul 2012 #30
guardian Jul 2012 #32
Jim__ Jun 2012 #9
laconicsax Jun 2012 #11
Jim__ Jun 2012 #12
hunter Jun 2012 #24
Javaman Jun 2012 #20
Glassunion Jun 2012 #22
ashling Jul 2012 #28

Response to n2doc (Original post)

Tue Jun 19, 2012, 04:32 PM

1. It explains why Mom was so good in choosing socks, I could never match socks

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Response to n2doc (Original post)

Tue Jun 19, 2012, 04:33 PM

2. Here is a graph.

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Response to Swede (Reply #2)

Sun Jul 1, 2012, 02:54 PM

25. Strawberry and magenta

are more red to me.

eggplant more blue.

flora, honeydew -> yellow.

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Response to Swede (Reply #2)

Mon Jul 2, 2012, 08:13 AM

29. I'm the opposite... I'm colorblind...

... so when I look at this or other similar charts, I see the same bands of colors repeating 2-3 times.

My vision reports 2 identical blue sections with an extra 3rd one of a different shade.

A repeating pattern from Salmon to Sea Foam.

And the reds fall closer to black and deep grays.

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Response to n2doc (Original post)

Tue Jun 19, 2012, 04:54 PM

3. I would think it would be fairly easy to find such people

The article says, "...because perceiving color is a personal experience, (the tetrachromats) would have no way of knowing they see far beyond what we consider the limits of human vision.

I don't think that's at all true. Tetrachromats should be hugely dissatisfied with computer monitors, color television, color printing, color photographs -- our entire world of tri-stimulus color media. All such media wouldn't look just a little bit off, they would be grossly inaccurate in their reproduction of many of colors these people could see directly with their eyes.

I think their own dissatisfaction would stand out pretty clearly when they hear other people praising the quality of a new TV or a photograph that looks crappy to their eyes, or when they look at at touched-up paint jobs that everyone else thinks looks good, but where they see very clear and messy blobs of mismatched color.

EDIT: On further reading the article, is seems like the difference in color perception needs training otherwise those possessing this ability ignore it. It could also be that the brain doesn't typically process the signals from the mutant cones as a separate channel of information from the information coming from close-but-not-quite-the-same cones.

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Response to n2doc (Original post)

Tue Jun 19, 2012, 05:41 PM

4. Some fighter pilots such as Chuck Yeager were know to have superior vision. It might be worthwhile

 

for the scientists to research whether any of the current fighter pilots are tetrachromats.

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Response to AnotherMcIntosh (Reply #4)

Tue Jun 19, 2012, 06:01 PM

6. As I understand it, only women can have tetrachromacy.

 

Color vision is X-linked. That's why men are around 100 times more likely to be color blind. Tetrachromacy would require a "normal" set of trichromatic genes and an "altered" set that allow for tetrachromacy. An altered set on it's own would merely result in a different perception of the hues trichromats can see rather than superior vision.

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Response to AnotherMcIntosh (Reply #4)

Wed Jun 20, 2012, 07:46 AM

19. Sharpness and colour perception are determined by different mechanisms

Think of it as the difference between a camera's lens and a camera's film.

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Response to n2doc (Original post)

Tue Jun 19, 2012, 05:50 PM

5. The tetrachromats would all be women.

The gene for one of the cones lies on the X chromosome -- tetrachromats would have two copies, and if they differ significantly then both copies would be expressed.

Men, having only one X chromosome, cannot be tetrachromats. Though depending on what X chromosome any particular man inherited from his mother, he might see a different set of 1 million colors than a man who inherited an X chromosome with a different variation of the cone gene.

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Response to n2doc (Original post)

Tue Jun 19, 2012, 06:07 PM

7. I want to see into the ultraviolet, dammit!

 

Birds, insects, and even turtles can do it, so why can't I just get gene therapy to see light at ultraviolet wavelengths?

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Response to laconicsax (Reply #7)

Tue Jun 19, 2012, 08:53 PM

10. Actually, I've heard that some people do see into the near ultraviolet.

Particularly people who have had cataract surgery. It appears that in some cases the artificial lens implants people get don't filter out as much of the UV as a natural lens does.

This isn't tetrachromacy, of course. The extra UV that gets through apparently acts like extra blue light as far as the effect on the colors you see.

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Response to laconicsax (Reply #7)

Wed Jun 20, 2012, 05:08 AM

16. Because you'll end up looking like this

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Response to Spitfire of ATJ (Reply #16)

Wed Jun 20, 2012, 05:10 AM

17. I'm pretty sure he only has monochromatic vision. n/t

 

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Response to laconicsax (Reply #17)

Wed Jun 20, 2012, 05:25 AM

18. He was going for a shell and missed that too

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Response to laconicsax (Reply #17)

Wed Jul 4, 2012, 05:47 PM

31. Yeah, white and non-white.

 

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Response to Spitfire of ATJ (Reply #16)

Sun Jul 1, 2012, 03:11 PM

26. He has optical rectitus.

(Shity outlook) Common ailment with republicans. He also has Bovine Oral Rectitus which leaks out uncontrollably.

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Response to n2doc (Original post)

Tue Jun 19, 2012, 06:34 PM

8. Just for fun, try taking this color test

I took this test once at work and only got two wrong out of one hundred.

http://www.xrite.com/custom_page.aspx?pageid=77&lang=en

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Response to PADemD (Reply #8)

Tue Jun 19, 2012, 09:27 PM

13. I scored 102

Not surprising as I already knew I was colorblind, haha.

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Response to PADemD (Reply #8)

Tue Jun 19, 2012, 10:40 PM

14. That's hard! I missed four.

I'm going to have my mom and my daughter take it, as I'm convinced they see more colors or colors more clearly than most do.

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Response to PADemD (Reply #8)

Wed Jun 20, 2012, 12:45 AM

15. I scored 4...much better then I thought I would do

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Response to PADemD (Reply #8)

Thu Jun 21, 2012, 04:55 AM

21. Woo! Scored 3!

 

I knew the three I got wrong were out of order, but no amount of shuffling looked right.

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Response to PADemD (Reply #8)

Thu Jun 28, 2012, 11:37 AM

23. 174? WTF?

My wife is going to give me so much shit over this. She already says I'm not allowed to teach our 2-yr old colors

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Response to PADemD (Reply #8)

Sun Jul 1, 2012, 03:29 PM

27. I scored an 8, which ain't bad, I guess. nt

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Response to PADemD (Reply #8)

Mon Jul 2, 2012, 10:21 AM

30. That's the same test they had over at Huffington post last week.

I scored a zero on it. Perfect color vision.

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Response to PADemD (Reply #8)

Wed Jul 4, 2012, 06:48 PM

32. 109 for me n/t

 

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Response to n2doc (Original post)

Tue Jun 19, 2012, 07:33 PM

9. It looks like the cone for red is highly polymorphic.

The red and green cones have a huge overlap in the colors they respond to. From wikipedia:



...

The opsins (photopigments) present in the L and M cones are encoded on the X chromosome; defective encoding of these leads to the two most common forms of color blindness. The OPN1LW gene, which codes for the opsin present in the L cones, is highly polymorphic (a recent study by Verrelli and Tishkoff found 85 variants in a sample of 236 men). A very small percentage of women may have an extra type of color receptor because they have different alleles for the gene for the L opsin on each X chromosome. X chromosome inactivation means that only one opsin is expressed in each cone cell, and some women may therefore show a degree of tetrachromatic color vision. Variations in OPN1MW, which codes the opsin expressed in M cones, appear to be rare, and the observed variants have no effect on spectral sensitivity.

...


So, is the implication that this fourth cone would have a peak response between the peak responses shown for red and green, maybe at about 575nm?

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Response to Jim__ (Reply #9)

Tue Jun 19, 2012, 09:06 PM

11. I think it would depend on the mutation.

 

While the implication seems to be that the fourth cone would peak in that green-yellow range, the lack of research in the area can't rule out other possibilities.

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Response to laconicsax (Reply #11)

Tue Jun 19, 2012, 09:26 PM

12. My thought is that the mutation that causes color blindness in men probably peaks ...

... nearer to green than normal.

Of course, with the red cone being highly polymorphic, there are probably women with different spectral versions of tetrachromatic vision. That difference could explain why most of the women they suspect have this vision haven't tested positive for it.

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Response to Jim__ (Reply #9)

Sat Jun 30, 2012, 09:11 PM

24. Our red-green discrimination is an evolutionary kludge.

Our fury distant ancestors lost two of their color receptors. Skulking about at night, maybe they weren't using them.

Our great ape ancestors regained trichromacy in a forking of the remaining red-green receptor.

The peak sensitivities of reptile and bird color receptors are evenly spaced.



http://en.wikipedia.org/wiki/Bird_vision





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Response to n2doc (Original post)

Wed Jun 20, 2012, 10:40 AM

20. RadioLab just did a show on this...

and what they found was pretty interesting.

They did locate a woman with this ability. She happened to be an interior designer.

They gave her several swatches of color to look at. All seemed, to the average viewer, to be the same color. However, when she viewed them, she was able to pick out the subtle differences in each as if they all were completely different colors.

But then something interesting happened. They asked a male artist to take the same test. He was also able to see the differences in color with the same accuracy as the woman.

The conclusion they came to was: while some woman may have this as an innate ability, it appears as if a person can also learn to hone their own ability.

Given the fact that the guy was an artist and is looking at color all day long, it could be the difference between someone who plays a piano as apposed to some who is a accomplished pianist.

The more you deal with color the better you get at seeing the various differences.

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Response to n2doc (Original post)

Mon Jun 25, 2012, 11:48 PM

22. This explains how my wife can see through my bullshit.

It all makes sense now.

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Response to n2doc (Original post)

Sun Jul 1, 2012, 05:03 PM

28. And that's no Bull, . . . Penn



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