May 13, 2010
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The Theory of Perception
Everything about vision is explained by the Trichromatic Theory. The theory describes a model of vision in which light is captured by three photopigments (erythrolabe, chlorolabe, and cyanolabe) in the retina. This sets off a metabolic cascade, and the light stimulus is converted into an electrical signal that travels through the retinal ganglion cells and optic nerve. The signal exits the eye via the optic nerve, optic chiasm, and optic tract and is transmitted to the brain at the lateral geniculate nucleus. From here, the signal is sent through the optic radiation to the occipital lobe at the back of the brain, where the electrical signal is translated into vision by the visual cortex. What we see in real life is dictated by the three photopigments’ ability to capture light. Each photopigment has a peak absorption wavelength, and we are able to discriminate color based on the relative absorption properties of the photopigments per wavelength of light. The theory infers that if we were to have a hypothetical fourth photopigment, we would be able to see colors that we currently cannot appreciate. Additionally, the theory also implies that if we were to have less than three photopigments (say, two), we would not be able to appreciate all the colors that we currently can see. Human beings with four photopigments do not exist, but there are people alive with only two photopigments. I am one of these people. I, along with five percent of all males, am colorblind.
I will never be able to describe to anyone exactly what I see, just as no one will ever be able to describe to me exactly what they see. However, I can tell you that my life is not like an episode of I Love Lucy; I do not see the world in black and white. I see colors, but I’m really not that good at distinguishing them. The best way I can explain this is with bananas. Whenever I see something that might be yellow, I compare it to a banana and ask myself, “Is that the same color as a banana?” The only reason I know that bananas are yellow is because EVERYONE knows that bananas are yellow. So, whenever I see a banana, I assume that it’s yellow. But unripe bananas are green, and those really throw me off. I pretty much suck at distinguishing a green banana from a yellow one, which is why I wait until my bananas have a bunch of black spots on them before I dig into them like a rabid monkey.
I suppose that’s a pretty lame way at perceiving the world, but that’s how it is. Our perception is limited by our own physiology. I don’t know if this has anything to do with who I am, but it probably does. I’ve been told on more than one occasion by more than one person that I’m kind of a weird dude and I have interesting perspectives on life and the world. I’ll admit that they’re probably right. I’m a complete nutjob! And since, as I described above, the eye is intimately connected with the brain, and since 90% of the information our brain processes is received from the visual system, I suppose it’s plausible that my brain processes information differently. I literally (and figuratively, I suppose) see things differently, which probably makes me think about things differently, too. It’s either that or myself just trying to make some transcendent realization that somewhat relates to what I do for a living.
But, then again, it’s only a theory.
Comments (4)
you should give David Hume for proposing this theory first.
When I was 8, I wondered if different people saw different colors. What I thought was green was what someone else really saw as blue, but since everyone agrees on grass being green (or brown if you’re in certain parts of CA), that we all THOUGHT we were seeing the same color. I was a weird kid.
how do you explain color to blind people
Strange … I thought you were only red-green colorblind. I’ve never met a colorblind guy with “yellow issues.”
It’s really interesting how people adapt to such differences, though. Never would’ve thought of the spotty banana thing. I know another guy who has to watch traffic lights very carefully because they all sort of look yellow to him. Instead he pays attention to the position of the lights (which is still tricky; I’m surprised he hasn’t gotten into more accidents).
Also, you’re not a nutjob. Quit complimenting yourself.