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The Neuroscience of Illusions and Dictionaries
Scientific American is running a pair of stories about what words and illusions can tell us about the brain. Mark Changizi of the Rensselaer Polytechnic Institute is interviewed about his research into the relationship between the mechanisms of the brain and the evolution of language. The second article contains a slide-show of various illusions and why the brain interprets them as it does.
Why do LED clocks jiggle up and down when I'm eating crunchy things?
it's a blue bright blue Saturday hey hey
I had always wondered why elephants had forward-facing eyes, since they are not predators... and this helps explain it. I had always supposed that it was because they were social animals, and communication ability and multiple individuals scanning for threats was better than one individual with a larger field of view. This makes even more sense if the scanning in a smaller area is more effective due to the binocular vision associated with forward-facing eyes.
"Trolls they were, but filled with the evil will of their master: a fell race..." -- J.R.R. Tolkien on Olog-hai
Maybe I missed something, but I found the second article to be a let-down.
(Warning for epileptics: if visual stimuli can set off a seizure for you, you should probably stay away from the following links. I am not susceptible, but I found the second link to be visually overwhelming at first.)
IMHO, more interesting galleries of examples can be found at Wikipedia's Optical Illusions page and at Michael Bach's 78 Optical Illusions & Visual Phenomena page.
You must have done something wrong. I opened the image in Photoshop and used the eye dropper to sample the pixels. The A and B squares are the same.
Another great resource for this stuff is the "Best Visual Illusion Contest of the Year" page that's sponsored by (and done at) the Vision Science meeting every year:
http://illusioncontest.neuralcorrelate.com/
These are the newest and most interesting illusions that are found every year. Some of them are very interesting and quite clever.
Fascinating really!
"It's a fact of neuroscience that everything we experience is actually a figment of our imagination. Although our sensations feel accurate and truthful, they do not necessarily reproduce the physical reality of the outside world. Although our sensations feel accurate and truthful, they do not necessarily reproduce the physical reality of the outside world."
I think you totally misunderstood what they were getting at, poorly chosen words. According to physics of relativity, "insideness vs outsideness" is an illusion of consciousness. Reality is a continuous field. i.e. If we were in a simulation you wouldn't know it. There is no object "out there" per se, all your mind is doing is discretizing a continuous surface of data that you percieve or have access to into chunked-objects that don't really exist. i.e. a tree is not seperate from the earth, which ultimately is not seperate from space, which is ultimately not seperate from the sun, all of these things are continuously connected in ways we don't fully understand.
How we currently interpret reality is based on what we think we know, not what we actually know. There's a huge difference. A color blind person interprets the features of world differently then someone with full color vision for example, and there are rare 'tetra chromats' that see the world in full four color vision.
The point is you there are gaps in what we are able to detect and perceive, what you ultimately are perceiving in the end is data, when you go to sleep for instance, you could die and not KNOW that you in fact have died, the only reasonable indicator that you have died would be the fact that you are no longer conscious but you wouldn't ever know that you were not.
http://www.post-gazette.com/pg/06256/721190-114.stm
Let us grant your second suggestion: that dichromatic vision is sufficient for detecting changes in emotional state. What that would mean is that the task requires no less than two kinds of photoreceptor, and that both dichromats and trichromats will become more common in the population than monochromats. However, you've given us no reason to think that the dichromats would be better off than the trichromats. We could end up with a majority trichromat population not because trichromats would be fitter than dichromats, but just because the original population had a mutant allele for trichromatism but none for dichromatism.
Of course, all my argument shows is that both Changizi and you would need to pursue other lines of argument to settle the dispute.
But in order to see red best, you need to be able to detect what is not red. If you want to see why, take a photo of a colourful scene then create two versions in Photoshop, make one greyscale, then on the other one, use the channels pallet to look at each channel separately. A bright red object in the red channel will look the same as a white object, while the other channels will show it as very dark. Obviously, human vision doesn't work exactly like this, but the same principle still applies: The best way to detect red is not just to see red in an otherwise grey world, but to have it contrast with other colours.
Of course, I don't entirely buy the blushing theory, either. And this isn't necessarily saying anything about the way vision actually evolved, as well. But I do think it shows that your reasoning in this case is wrong, even if you are right. The food theory has always made more sense to me when you look at how other species have evolved.
I've heard about this before, and I think it's vaguely true. I can easily pick out 3, 4, or even 5 objects without having to count, of having them in any particular formation/sequence. But if you gave me 6 objects in a random configuration (without showing me a lesser number before hand), I really would have to count. Case in point is Roman Numerals (and Chinese I guess). Roman Numerals (now) goes up to III before IV (though apparently it use to go up to IIII). Chinese does the one stroke, two stroke, three stroke thing too, before switching to other symbols (though apparently the Chinese four also derived from a 4 stroke character too).