One of the classic questions of cognitive science is “Why do things look as they do?” Two opposing answers to this question are “Things look as they do because we are the way we are,” and “Things look as they do because the world is the way it is.”
On the one hand, things look as they do because the world is the way it is. Photons are emitted by light sources, bounce off of things, and into our eyes. The wavelengths of these photons determines the colors we perceive.
But on the other hand, things look as they do because we are the way we are. Any optical illusion is evidence of this, because in an optical illusion we perceive something that is contrary to what exists in the world.
The Cognitive Science classes I’ve taken here at Berkeley concede the necessity of environmental stimulus, but beyond that are pretty organism-centric. The phenomenon of optical illusions (among others) is taken as evidence that our experiences of the world are dependent on our biology.
But “because we are the way we are” always seemed to be missing something for me, and today I figured out what it was.
Why do things look as they do?
Because we are the way we are because the world is the way it is.
We see the colors we do because our eyes are visible to a specific wavelength of light. Why are our eyes sensitive to visible light instead of infrared? Because the majority of the light that reaches the surface of the earth is in that wavelength. Why does the wagon wheel illusion occur? Because the proximity heuristic used to help solve the motion correspondence problem was more accurate than other failed (and hence unknown) heuristics, which gave the organisms with those heuristics an advantage.
If our species had developed on a world where gravity behaved differently, or where other wavelengths of light predominated, we would be different organisms, and we would most likely experience the world differently. Our brains were shaped by the environment in which they developed, making our experiences just as much a product of our environment as they are a product of our biology.
(Please note that I am not talking about “nature versus nurture.” That’s a whole other can of worms that I’m not even going to get into.)