Optical illusions are perceptually deceptive phenomena that arise when we experience a stimulus which is not accurately represented by the visual system. They involve errors in the sensory information that is encoded in the visual cortex, as well as in the interpretation of the incoming visual cues by the higher level visual processes. Such illusions can take many forms, ranging from illusions of colour, shape and motion to distortions of individual visual elements or whole scenes. Regardless of type, these illusions demonstrate the capacity of our perceptual systems to be deceived and, in many cases, influenced by the context in which they are experienced.

See also: right hemisphere, left hemisphere, corpus callosum, neural network, split brain