when we look at optical illusions such as the one in the previous post, we see that things aren`t as they seem. why does a pattern begin to move when we look at it? who`s to say that it doesn`t move of it`s own accord?
who`s to say that it`s moving?
there are those rare people who don`t actually see movement when they look at the image. i imagine that they`re puzzled to hear that some people see the images moving.
so, how does the image actually move?
the surface of the retina, which is the inside surface of the back of the eye, is covered with nerve clusters called rods and cones. these nerves convert light into colours, shapes and movement that the brain then converts back into pictures of the world. i have oversimplified this process for descriptive purposes, but it is an accurate model nonetheless.
when the rods and cones become fatigued, as with the complex pattern in the optical illusion, then other rods and cones are recruited to maintain the image in the mind. these other rods and cones are located on slightly different areas of the retina, giving the illusion of movement to the brain.
this fatigue/re-recruitment process is true of all aspects of the human system, from brain cells to muscle cells. the eye is no different.
our body adapts to fatigue by adjustng it`s self to perpetuate operation.
it`s a good thing too. unless what it`s adapting to is an illusion. then it gets fooled.
so what`s real then?