Perception: how the external world gets represented in our brain/mind so that we can understand and act upon what"s going on around us. Agnosia: deficit in recognition despite normal vision. Apperceptive agnosia: unable to name, match, or discriminate visually presented objects. Can"t combine basic visual information into a complete percept, therefore they should deficits in copying as well. Associative agnosia: cannot associate a visual pattern with meaning, can"t recognize what they see. Able to combine visual features into a whole, so they are able to copy well. The experience error: what you see isn"t what you get. Experience error is false assumption that the structure of the world is directly given from our senses. Retinal activation can be organized in an infinite number of ways. Impression of seeing continuous image of world, but eyes follow a series of fixation-saccade cycles. Computational approach: concerned with discovering how the brain represents and interprets the distal stimulus.