In perception, adaptation refers to the adjustment of sensitivity of sensory mechanisms in response to particular sensory inputs. For example, after putting on a wrist watch, the feeling of the watch touching the skin will soon be gone, a manifestation of sensory adaptation. Similarly, when wearing a pair of tinted glasses, initially the world will appear as tinted with the colors of the lens, but soon one will no longer notice the altered color and the world will look normally colored. As Aristotle noted more than 2,300 years ago, our senses are not static, and after looking at moving objects such as a waterfall, then static things could be seen as in motion. This is an example of seeing a motion aftereffect, which is another ...