Neat optical illusion
- Thread starter Forty-Two
- Start date
-
- Tags
- optical illusions
Dark Jaguar
Graduate Poster
- Joined
- Jan 19, 2006
- Messages
- 1,666
Wow, that's totally alien to me. Are you sure you aren't seeing another shade of green or something and thinking that you are seeing a distinct other color? I have had the experience of seeing a lot of darker and lighter shades of green, or mostly green with some blue, and been able to distinguish each as a distinct color in the same way you would distinguish different shades of grey as their own color, but if suddenly a red thing is tossed in there, bam, that is far more distinctly a different color.
Blue and green seem somehow "closer" to each other than red is to either one though. I wonder if that's the normal look of them? I've never confused "true blue" with "true green" and those two do look distinct, just not AS distinct. Yellow, which I realize now is pretty much just an illusory color, seems far more of a completely distinct color from any of the others than blue and green do from each other. Yellow is like red in it's distinctness, though ligher shades are like THIS close to being plain ol' white.
At any rate, strawberries look completely different than the leaves they are intermingled with.
Mr. Scott
Under the Amazing One's Wing
- Joined
- Nov 23, 2005
- Messages
- 2,546
Denying Conscious Sensations
Another hypothesis relates to our malady du jour Asperger's Syndrome. It's a mild form of Autism that makes many otherwise-brilliant people rather zombie-like. A famous Asperger's person is Temple Grandin, an author recently brought up in the "Do animals feel?" thread. Could consciousness deniers, including those in the Artificial Intelligence field, be missing a good copy of a gene that endows us with conscious sensations? This would be like a color blind person saying people who see red and green are making something up that isn't there.
I have a friend who was once very close to an Asperger's sufferer who was brilliant but pretty much a zombie. So clever, in fact, that he learned how to fake emotions to get along with people, and could readily admit to faking them. They walk among us!
(Could they pass the Turing Test?)
I can imagine how listening too closely to an Asperger sufferer's theories about consciousness could lead one astray.
Another hypothesis relates to our malady du jour Asperger's Syndrome. It's a mild form of Autism that makes many otherwise-brilliant people rather zombie-like. A famous Asperger's person is Temple Grandin, an author recently brought up in the "Do animals feel?" thread. Could consciousness deniers, including those in the Artificial Intelligence field, be missing a good copy of a gene that endows us with conscious sensations? This would be like a color blind person saying people who see red and green are making something up that isn't there.
I have a friend who was once very close to an Asperger's sufferer who was brilliant but pretty much a zombie. So clever, in fact, that he learned how to fake emotions to get along with people, and could readily admit to faking them. They walk among us!
(Could they pass the Turing Test?)I can imagine how listening too closely to an Asperger sufferer's theories about consciousness could lead one astray.
Last edited:
Mr. Scott
Under the Amazing One's Wing
- Joined
- Nov 23, 2005
- Messages
- 2,546
Benham's Wheel -- Colors from B&W
The optical Illusion Benham's Disk should be mentioned here. You spin a wheel made up of nothing but Black and White markings, and colors appear. Interesting references there for articles on "subjective colors." I'd like to know if color blind people see colors in it they've never seen before.
The optical Illusion Benham's Disk should be mentioned here. You spin a wheel made up of nothing but Black and White markings, and colors appear. Interesting references there for articles on "subjective colors." I'd like to know if color blind people see colors in it they've never seen before.
Mr. Scott
Under the Amazing One's Wing
- Joined
- Nov 23, 2005
- Messages
- 2,546
I can't recall the actual study and that may be a false memory, but I'm pretty sure I learned that deaf people (maybe only young ones) could hear for the first time through direct cochlear nerve stimulation.
Then again, spontaneous atrophy being what it is, I'd not be suprised to learn that born-blind people, by adulthood, have had their visual systems rendered inoperative or reassigned and are therefore unrecoverable. I'll backpedal on that point.
Rat
Not bored. Never bored.,
Yes, they do to me as well, when I look at them individually. It's kind of impossible to explain, or, I guess, to imagine. Red and green (I am, of course, red/green colour-blind) look very different to me. I certainly perceive them as two separate and very different colours. But the strawberries just don't stand out for me.
I also perceive green as closer to blue. I don't know if there's a clue in your allusion to shades of grey. If, in good light and minimal shadows, you take a greyscale picture of a strawberry field, I suspect that the strawberries and the accompanying leaves would come out a similar shade of grey to each other. I further suspect that this would not be the case if the strawberries were yellow. And indeed, I can pick out unripe (yellow) strawberries with no problem. But when I've tried to explain it that way before, people come to the conclusion that I must see in black and white, which is patently not true.
And it can't be that I can tell the colour of each individually only because I know already what colour they are, because if you held up cards of red and green, I could get them right every time. If, however, you arranged the cards (assuming there were a lot of them) in a pattern so that the red cards made an image among the green ones, I would have difficulty picking that pattern out. This is a simplified version of how the splatter pattern tests work, of course.
On the other hand, I do have real difficulty telling green and brown apart. If you don't have blue eyes, I'm unlikely to be able to tell you what colour your eyes are. Unless you're albino. Truth be told, I don't know what colour my own eyes are, but I think I remember them as brown. Unless it's a very vivid green, or a very muddy brown, I think this is were I really do rely on knowing beforehand what colour something is. I know that wood is brown and (living) leaves are green. But if you're wearing an item of clothing (say, a t-shirt) that could be either, it's unlikely I could tell, again, unless it was were vivid-green/muddy-brown.
It makes for some interesting moments, but unless you have a career planned as a train driver or electrical engineer (both of which are barred to me), it's hardly an affliction. And I'm told it does have some advantages, which may explain why it continues to exist, in other apes as well as humans. There is a story (I don't know if it's true) that bomber crews used to like to take a colour blind crew member on board, because while they miss certain things, there are other things that they see rather vividly, and thus can pick out camouflaged targets. This may also apply to gathering fruit for apes. Certainly if I see gold against brown, the contrast is almost painful to me, with a shimmering line between the two, and I'm told that others (even some colour-blind people) don't get this effect, though I have heard it from some other colour-blind people.
Cheers,
Rat.
What a great question! I would predict, based on a behavioral view of language learning, that color blind individuals would see the same colors they do in response to other stimuli. But it is a falsifiable prediction, which is the great thing about empiricism. It would be a simple test, too! We could do it with only the color-blind people who have posted to this thread, and a couple of print-out disks.
(Grunfeld & Spitzer (1995, Vision Research) take a look at Benham's Disk...from their abstract: "... a general spatiotemporal model for the subjective color phenomenon of Benham's disk based on general cell response to inhibitory stimulation and differences among 3 color pathways. The model takes into account known spatial and temporal properties of the color-coded ganglion cells, including specific nonlinearity (the rebound response) which is suggested to initiate the effect.")
A quick and cursory EBSCOHOST search suggests that there are critical periods. Looks like after people have learned to recognise speech, they can lose hearing for decades (and have auditory cortex taken over by other processing) and still regain it (and retake that cortex. Very cool...), but if hearing is lost early, the longer the wait before a cochlear implant, the more difficult it is to gain hearing. Hearing loss at a younger age makes speech recognintion more difficult, although tone recognition may be possible.
Did not see anything about congenitally deaf with cochlear implants in adulthood. Kids, yes. Cats, yes. But it was a quick and cursory search.
Jeff Corey
New York Skeptic
- Joined
- Aug 2, 2001
- Messages
- 13,714
Memory serves and aces, Merc. John Dalton, 18th century English chemist first described this condition that he had. Red-green colorblindness(protanopia) is still called Daltonism, at least in French,
I have heard also the stories about the bomber crews.
The perception of a given color, from a given stimulus, depends on both the wavelengths coming from the stimulus ("stimulus" broadly defined, including information both at and surrounding the target), and the sensitivity of the retinal cells to those particular wavelengths. Paints (including camouflage colors) that are blended to reflect a particular spectrum, may come up with, say, a particular green with several different combinations of pigments. That green may be the result of essentially a single wavelength of light, or a combination of two, three, or many wavelengths, each combination resulting in the same combination of signals from the three photopigments. If, however, you change either the sensitivity of the retinal photopigments (as with Rat's colorblindness) or the light illuminating the paint, colors that looked identical now can look terribly different.
Anyone can see this--it does not require getting rid of a set of cones--by visiting your local paint store. Most have learned that they must have a display that allows customers to see how different paint colors look when combined (walls & trim, for instance), and will have 3 or 4 different light sources to use for this purpose. Natural sunlight, incandescent light, fluorescent light, and perhaps one or two others I can't think of right now, each give a very different spectrum to reflect off of the paint samples. (Greens are particularly difficult to match under both incandescent and fluorescent light.) The spectral curves of the light sources are very different--the full spectrum of sunlight, the "redder" incandescent light, the discrete peaks of the fluorescent spectrum. Paints which look like a good match in sunlight can look horrible in fluorescent light (similar effect--take photos of someone's face, with no camera flash, by sunlight, incandescent, fluorescent, candlelight, and compare them).
Dang, I am wordy. Bottom line is, what looks like a match to a trichromat may stand out brightly to a dichromat.
alfaniner
Penultimate Amazing
Nope -- nuthin' but black & white circles.
gumboot
lorcutus.tolere
- Joined
- Jun 18, 2006
- Messages
- 25,327
You get some really trippy effects like that in film using foreshortening (using a lens with a long focal length which reduces depth perception and "Squashes" the image).
Like in the film Lord of the Rings...
When Frodo and Gandalf are riding on the cart they're actually about 14 feet apart. Similar in the scene where Gandalf and Bilbo are having tea at Bilbo's house.
Completely weird on set to see these actors performing scenes at opposite ends of a room....
Just had to trust PJ knew what he was doing!
-Andrew
Beerina
Sarcastic Conqueror of Notions
- Joined
- Mar 3, 2004
- Messages
- 34,334
I notice a similar issue with the ring of pink dots. If you try to follow the green dot, it disappears. This seems to indicate that this is a physiological "burn in" issue rather than some mental trick of the brain. Like smell receptors, perhaps the rods and/or cones need a few seconds to relax without stimulation in order to feed the purest signal again, rather than a corrupt negative signal?
Almo
Masterblazer
I have loads of eyeball control, and it took me years to see stereograms. My problem is there are two ways to set them up: 1) crossed eyes see it correctly 2) eyes drifted apart see it correctly. It was determined by someone that the best way was method 2). I can't drift my eyes apart, but I can easily cross them and hold them there. It ocurred to me that crossing should work once I saw some stereograms that were made of visible patterns instead of dots. Then I could see them easily, though the 3D was backward.
BTW... I've played the StereoQuake mod, which displays two side-by-side views. Cross your eyes quite a lot, and you get full 3D quake. Was great for about 15 min when the headache set in. MetalPig
Illuminator
I can cross, but then I can't focus. Fortunately the drifting works for me, although sometimes I need to remove my glasses (and get real close to the picture
).GreedyAlgorithm
Muse
- Joined
- Aug 29, 2005
- Messages
- 569
Long lasting illusion
Cribbed from boingboing. It's been going strong for 10 minutes now, and the claim is that it will last for at least several hours.
Cribbed from boingboing. It's been going strong for 10 minutes now, and the claim is that it will last for at least several hours.