The Human brain put images together because they have learned to expect things, and sometimes the data might get a little confused.

We may see an illusion because we know what we are expected to see, even though part of a picture or design may not be completely there. The basis of this is in how we perceive things.

That almost explains everything right there. If our brain and eyes did not function like they do, we would not see illusions like we do.

One example of optical illusion is the television. The television is just shows us a continuous flow of still pictures, one right after the other. Our eyes along with your brain fill in all of the empty spots. Our brain has learned to expect movement. As a result, our brain can fill in all of the missing pieces and the television appears to be actually moving to you, even though it really isn’t!

A computer monitor is also one big optical illusion. Sometime when you have a chance, look at a computer screen really close for a minute or two. You will notice that you computer screen is made up of tiny red, green, and blue dots. The illusion is, you see more than just red, green, and blue dots; you see thousands of different colors. Our brains put the red, green, and blue dots together to make the colors.

Optical illusions just trick you into seeing something else. They are an error in our perception of the illusion.