Elusive Illusions

Most of us have seen an optical illusion before. We know that through our sense of sight they trick our brains into seeing what may or may not be real. But how do they work?

There are a number of factors that contribute to a given illusion. One of the simplest to understand is the ambiguous illusion. This type is a picture or object that simply creates a perceptual switch between two alternative interpretations. A simple well know example of this is the Rubin vase.

The next type of illusion is the distorting illusion which distorts size, length or curvature. Our brain learns to make very efficient interpretations of 3D scenes which is why when some goes away from us, we do not see them as getting shorter. Or when we stretch one arm and look at the two hands we do not see one hand smaller than the other. Below, the seemingly imperfect circle is an example of this.
Another type of illusion is the sometimes frustrating paradox illusion which is generated by objects that are paradoxical or impossible. Because of this, our brain has a hard time of interpreting these illusions such as the flow of the water below.

Sometimes it can be a little disconcerting to know how easily the mind can be tricked...