Perceptual processes - illusions (external link)

Use this link to explore what optical illusions tell us about perception.

To perceive is to create a figure or shape that does not necessarily appear as such in the real world but that we can represent mentally so that we can recognize it under various conditions (for instance, when it is partly hidden). Hence, by studying the way that the brain fills in missing or ambiguous visual information, we can learn a lot about the way that we perceive the world. Optical illusions provide fertile ground for such study, because they involve ambiguous images that force the brain to make decisions that tell us about how we perceive things.