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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.
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.
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.
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?
Dachannien's explanation is the correct one. LEDs sometimes use 'multiplexing' power sources, causing the segments to flicker when you move your eyes quickly. This is also true of some of the newer LED automobile tailights.
...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)
Actually a short film on National Geographic made a good point.
If we didn't have forward facing eyes, just how effective would our hands be? We'd have lots of trouble grabbing things, because we'd have a very hard time judging the proper distance. Same with manipulating things.
Granted, elephants aren't exactly known for having hands, but they do use their trunk for a LOT of gripping and manipulating. How much trouble would they have, if they didn't have forward facing eyes?
We do not live in the 21st century. We live in the 20 second century.
That would be pretty nasty for a biped--or anything of substantial size, really. Chameleons can get away with it since they don't have to worry about falling down or running into things. Unfortunately, having eyes that can move about like that requires putting them outside the skull to some degree, which puts them in serious danger. One bad headlong rush into a tree or down a flight of stairs could blind such a creature forever.
I can discern Pulse-Width Modulated LEDs without eating :) By rapidly oscillating my eyes I can tell you in a second which light sources in a room are PWM. Car brake lights, dashboard lights, billboard signs, power LEDs - it's surprising how much equipment is now PWMd. That unfortunately includes other POV-based technologies like DLP. I see the rainbow effect in every single-chip implementation that I've ever come across.
"Nine times out of ten, starting a fire is not the best way to solve the problem." - my wife