The Mystery of Tetrachromacy • Hacker News Board

Re: The Mystery of Tetrachromacy

#21

Post by jhanschoo » Sun, Dec 20, 2015, 9:10 PM UTC

qb45 wrote: post #18

I wonder how those poor women deal with RGB displays. It must feel weird to see a difference between red+green and actual yellow. Although, on second thought, color vision doesn't seem to work perfectly anyway. I never understood how red+blue can be perceived the same as far violet, it just doesn't make sense if you look at those frequency response curves.

I doubt it will be that bad. It will probably seem a little more dull, like some of the colorblind simulators you can find around the net. It's probably not just screens; pigments have the color they have because they reflect certain wavelengths, tuned to the proportion that a trichromat would consider identical. A tetrachromat is almost certain to notice that pigments of pictures on paper might be drastically different in color to the color of the objects the pictures are supposed to represent.

The brain doesn't perceive color just by addition of the stimulation of the cones. Your red and green cones are still (slightly) stimulated when you see blue, and your brain tells you that blue is the color; with violet, the stimulation among the cones have a different proportion, hence violet. Incidentally, this is also why the sky appears blue; the sky is too polluted by other wavelengths to appear violet.

Re: The Mystery of Tetrachromacy

#22

Post by scott_s » Sun, Dec 20, 2015, 9:29 PM UTC

OopsCriticality wrote: post #11

peter303 wrote: post #7

Scientists are looking at direct delivery of gene therapy to retinal cells to cure serious eye diseases like macular degeneration, pigmentosa blindness, etc. Should this work well, then the next step would be lesser conditions like male color blindness. I read of some successful attempts to give dicromatic animals, genrally carnovoires, the trichromatic gene directly to the retina. These subjects can be tested by giv…

> The next step, more controversial, would be super-vision of tetrachromacity, perhaps infra-red and ultra-violet sensitivity. Night vision glasses no longer needed for enhanced soldiers. Utter poppycock. The cornea and lens in humans are UV opaque, which is a very good thing because UV light is damaging. People without a lens (aphakia) are reported to perceive UV light, but this is otherwise an undesirable condition…

Your comment would be much better without the first line.

Re: The Mystery of Tetrachromacy

#23

Post by GFK_of_xmaspast » Sun, Dec 20, 2015, 9:46 PM UTC

guard-of-terra wrote: post #13

peter303 wrote: post #7

Scientists are looking at direct delivery of gene therapy to retinal cells to cure serious eye diseases like macular degeneration, pigmentosa blindness, etc. Should this work well, then the next step would be lesser conditions like male color blindness. I read of some successful attempts to give dicromatic animals, genrally carnovoires, the trichromatic gene directly to the retina. These subjects can be tested by giv…

I don't think we can get good infra-red vision. Creatures with infra-red vision are usually cold blooded. We shine too brightly in infrared from within to be able to see something outside. But tetrachromacy should rightfully belong to us. It was lost by our pre-mammal ancestors, while reptiles still have base tetrachromacy, and some fish perceive even more colors. Most animals only perceive two colors and grow two pi…

> We shine too brightly in infrared from within to be able to see something outside.

Going by wikipedia, humans radiate in the 20-37THz range, which is a long long way away from the 430THz where visible light starts.

Re: The Mystery of Tetrachromacy

#24

Post by qb45 » Sun, Dec 20, 2015, 9:51 PM UTC

jhanschoo wrote: post #21

qb45 wrote: post #18

I wonder how those poor women deal with RGB displays. It must feel weird to see a difference between red+green and actual yellow. Although, on second thought, color vision doesn't seem to work perfectly anyway. I never understood how red+blue can be perceived the same as far violet, it just doesn't make sense if you look at those frequency response curves.

I doubt it will be that bad. It will probably seem a little more dull, like some of the colorblind simulators you can find around the net. It's probably not just screens; pigments have the color they have because they reflect certain wavelengths, tuned to the proportion that a trichromat would consider identical. A tetrachromat is almost certain to notice that pigments of pictures on paper might be drastically differ…

Actual violet (like UV LED or mercury lamp) should stimulate almost exclusively S cones. But it turns out that if you take blue, which stimulates M and L more than violet, and then add even more L stimulation, you end up with something that "feels" more violet than blue (at least to me). This is what bothers me. It looks like two distinct inputs producing the same output, even though there exists an intermediate input which produces different output.

Re: The Mystery of Tetrachromacy

#25

Post by lsh » Sun, Dec 20, 2015, 10:00 PM UTC

scott_s wrote: post #22

OopsCriticality wrote: post #11

Earlier quoted context omitted.

> The next step, more controversial, would be super-vision of tetrachromacity, perhaps infra-red and ultra-violet sensitivity. Night vision glasses no longer needed for enhanced soldiers. Utter poppycock. The cornea and lens in humans are UV opaque, which is a very good thing because UV light is damaging. People without a lens (aphakia) are reported to perceive UV light, but this is otherwise an undesirable condition…

Your comment would be much better without the first line.

And your tepid comments are just as useless.

Re: The Mystery of Tetrachromacy

#26

Post by neurosphere » Sun, Dec 20, 2015, 10:13 PM UTC

acchow wrote: post #9

It opens with an Australian painter who displays her extraordinary vidual experiences in her art. But if she was born this way, why would she find it extraordinary?

Hi! I wrote the Neurosphere article you're discussing, and noticed this lively comments section. I agree with the question you're asking - if she was born this way, why did she question it? From the research I did on her life, it appears that she always assumed people could see these colours, and apparently when teaching her students in art school she would try to say things like "Try to depict all the colours you see in this leaf, like the turquoise and orange on the sides..." and her students often just found it too embarassing to tell her they didn't see any of these colours. She slowly started realising that her colour perception may be different, until one day a neurology student taking her class suggested she took a genetic test. That's it. Since then I suppose she has really harnessed the results of the test to market her vibrant art as reflecting her 'tetrachromatic reality'. Some people have commented on Twitter questioning this, and it's something I think I will write about in the near future because it's a completely fair point.

Re: The Mystery of Tetrachromacy

#27

Post by nl » Sun, Dec 20, 2015, 11:14 PM UTC

OopsCriticality wrote: post #11

peter303 wrote: post #7

Scientists are looking at direct delivery of gene therapy to retinal cells to cure serious eye diseases like macular degeneration, pigmentosa blindness, etc. Should this work well, then the next step would be lesser conditions like male color blindness. I read of some successful attempts to give dicromatic animals, genrally carnovoires, the trichromatic gene directly to the retina. These subjects can be tested by giv…

> The next step, more controversial, would be super-vision of tetrachromacity, perhaps infra-red and ultra-violet sensitivity. Night vision glasses no longer needed for enhanced soldiers. Utter poppycock. The cornea and lens in humans are UV opaque, which is a very good thing because UV light is damaging. People without a lens (aphakia) are reported to perceive UV light, but this is otherwise an undesirable condition…

Utter poppycock.

That seems... strong, especially if referring to the "Night vision glasses no longer needed for enhanced soldiers" bit.

They eventually formulate a chlorin e6 solution for human use. A few drops are dripped into Licina’s eyes, and they had him look for people hidden among trees as well as symbols on objects in dim light. Licina seemed to perform a lot better than the four other people who did not get eyedrops.

http://gizmodo.com/the-real-science-behind-the-crazy-night-v...

Re: The Mystery of Tetrachromacy

#28

Post by Someone » Mon, Dec 21, 2015, 12:05 AM UTC

qb45 wrote: post #24

jhanschoo wrote: post #21

Earlier quoted context omitted.

I doubt it will be that bad. It will probably seem a little more dull, like some of the colorblind simulators you can find around the net. It's probably not just screens; pigments have the color they have because they reflect certain wavelengths, tuned to the proportion that a trichromat would consider identical. A tetrachromat is almost certain to notice that pigments of pictures on paper might be drastically differ…

Actual violet (like UV LED or mercury lamp) should stimulate almost exclusively S cones. But it turns out that if you take blue, which stimulates M and L more than violet, and then add even more L stimulation, you end up with something that "feels" more violet than blue (at least to me). This is what bothers me. It looks like two distinct inputs producing the same output, even though there exists an intermediate inpu…

Two distinct inputs producing the same output is metamery. https://en.m.wikipedia.org/wiki/Metamerism_(color).

Without it, color printing and color televisions would be way harder to create.

Re: The Mystery of Tetrachromacy

#29

Post by guard-of-terra » Mon, Dec 21, 2015, 7:45 AM UTC

GFK_of_xmaspast wrote: post #23

guard-of-terra wrote: post #13

Earlier quoted context omitted.

I don't think we can get good infra-red vision. Creatures with infra-red vision are usually cold blooded. We shine too brightly in infrared from within to be able to see something outside. But tetrachromacy should rightfully belong to us. It was lost by our pre-mammal ancestors, while reptiles still have base tetrachromacy, and some fish perceive even more colors. Most animals only perceive two colors and grow two pi…

> We shine too brightly in infrared from within to be able to see something outside. Going by wikipedia, humans radiate in the 20-37THz range, which is a long long way away from the 430THz where visible light starts.

Most things of interest also radiate in the same range.

Re: The Mystery of Tetrachromacy

#30

Post by dang » Mon, Dec 21, 2015, 8:12 AM UTC

lsh wrote: post #25

scott_s wrote: post #22

Earlier quoted context omitted.

Your comment would be much better without the first line.

And your tepid comments are just as useless.

scott_s was right, because the GP broke the HN guidelines by name-calling (in an otherwise fine comment). Your comment does too. Please don't do that.

https://news.ycombinator.com/newsguidelines.html