The following are monocular depth cues: texture gradient (textured surfaces appear coarser at close range), interposition (an obstructed object appears more distant) and familiar size (knowledge about an object's usual size can influence perceptions of closeness). Convergence is a binocular depth cue and refers to the convergence of the eyes toward each other when looking at objects close by.
Binocular cues are a source of information about depth and distance and consist of retinal disparity (the different image received by each retina) and convergence (close objects require retinal convergence while distant objects require retinal divergence).
The Müller-Lyer illusion stems from misinterpretation of depth cues such as linear perspective and cultural factors such as the 'carpentered world hypothesis'. This idea holds that the nature of architecture in a culture influences the tendency to experience particular illusions. People reared in cultures without, for example, rectangular buildings and angled roofs, should be less susceptible to the Müller-Lyer illusion because they lack experience with
Helmholtz recognised that the brain adjusts for distance when assessing the size of objects; a process he called unconscious inference because people have no consciousness of the computations involved.
Thereceptivefieldsofneurons that detect motion grow larger with each 'step' along the processing stream in the brain. Several ganglion cells project to the motion-detecting neurons in the thalamus, with several of these thalamic neurons feeding into the motor sensitive neurons in the primary visual cortex. Information then travels through a region of the temporal lobe (the medial temporal (MT)) to the parietal lobe. The receptive fields in the MT are larger than those in the primary visual cortex.
According to Biederman's recognition-by-components theory , incomplete figures are recognised quickly, as long as: