An efferent component in the visual perception of direction and extent.

After outlining the history of motor theories of visual perception, a new theory linking information extraction patterns, specifically adapted for the guidance of eye movements, to the visual perception of direction and extent is presented. Following a brief discussion of comparative and physiological considerations, a research strategy to test for efferent involvement in visual perception in humans is presented. In seven demonstration experiments, predictions from efferent considerations are used to create a new set of illusions of direction and extent and to demonstrate new predictable variations in the magnitude of some classical illusion figures. Another demonstration illustrates that systematic changes in visual perception occur as a function of changes in motoric demands, even in the absence of any configurational changes in the stimulus. A final section shows the relationship between attention and efferent readiness and their interaction in the formation of the conscious visual percept. From a historical perspective, most contemporary theories of visual perception are quite conservative. This conservatism springs from an apparent acceptance of the premise that any proper analysis of visual experience must avoid reference to nonvisual mechanisms, except for labeling and semantic aspects