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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.
Link to the one-page/print version of the dictionary article and the meat of the illusion article
Also, a summary of the illusion article: The brain uses context, rather than absolute sampling.
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
In the first FA, Changizi states his hypothesis that primates evolved color vision in order to detect changes in emotional state indicated by things like blushing/flushing of the face. I find this a bit problematic, primarily because it doesn't explain why our vision evolved to respond to three different wavelength ranges of light (red, green, and blue). It would make more sense to have only evolved cones responsive to red light, or perhaps red and one other color, if that were the only reason.
It seems to me that a more reasonable hypothesis is that trichromatic color vision co-evolved along with the colorings of fruits that primates would find nutritious. Emotional cues seem like a more subtle issue - as well as a mostly-solved problem - that would have taken advantage of color vision that was already partially or fully evolved.
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.
Is anyone else having trouble reading the second article? The image on the left keeps distracting me, with its pretend turning of ultimate attention attainment.
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.
I'm with you on this. Major suckage.
As interesting as the idea (of developing visual acuity and color sensitivity) is, TFA teases us. It mentions that we developed a sensitivity to red because of the blushing mechanism (never mind that people of color probably do not blush like whites), but doesn't give us much more. A slideshow of optical illusions? Whee.
That being said, it's a compelling idea, but it really belongs in the realm of science fiction and historical fantasy.
The letter "Y" looks like it does, becaues it looks like a tree? "A" looks like a mountain?
Meh.
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!
Quoting from the slide show link:
The whole philosophy of perception that this quote embodies is fundamentally wrong. As an example of this, take a look at the first so-called "illusion" in the slideshow: the Edward Adelson checkerboard-and-shadon example. This is called an "illusion" on the basis that our eyesight "misleads us" by telling us that a light square in the shadow is lighter than a dark one in the light, whereas they are, supposedly, "the same color." By "the same color," what they seem to mean is that the stimulus, i.e., the rays of light reflected or emitted from the squares that hit our retina, have the same spectrum and intensity.
What they're missing is that the point of vision, and perception in general, isn't to give us information about the rays of light that hit the retina. What vision does is give us information about the objects in our environment, which reflect or emit rays of light. The reason we see the two squares as having different colors, despite the fact that our retinas are getting the exact same pointwise stimulus from them, is because the visual system, using contextual information about light and shadow across the whole scene, can figure out that the surface spectral reflectivity of the two squares must be different. Square B looks lighter than square A because the visual system judges, correctly, that it must reflect more light. Or put alternatively: the visual system figures out that if the two squares were in the same light, the point stimulus from the reflected light rays would be different.
This is accurately reproducing an aspect of the physical reality of the outside world; vision is accurately reproducing the spectral reflectivity of surfaces in our environment, at the apparent expense of failing to reproduce the spectral distribution of the rays of light that hit our retina. But of course, the answer to that one is that the rays of light aren't the object of visual perception, they're just the means.
Seeing the squares as different colors is not an illusion. There is only one visual illusion in that example, and they don't remark on it: the illusion of seeing, in a flat surface, a 3D scene with light and shadow. The judgement that the two squares have different colors follows from that, because in the real-world scene the image depicts, those squares would in fact be surfaces with different colors when seen under the same light.
Are you adequate?
...strong AI cannot come from the processing of real data. That is not how minds work. Minds exist in a self-contained virtual reality that are periodically updated with real-world sensory data. This is why autism can impact the flow of that data and its connectedness without impacting the underlying mind. They're simply not associated in that way.
It's a small world and it smells funny; I'd buy another if it wasn't for the money; Take back what I paid (SoM)
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).