Gestaltzerfall (German for "shape decomposition") refers to a type of visual agnosia and is a psychological phenomenon where delays in recognition are observed when a complex shape is stared at for a while as the shape seems to decompose into its constituting parts. With regards to kanji, a study has shown that delays are most significant when the characters are of the same size. When characters to recognize are of different sizes, delays are observed only when they are of different patterns.
The phenomenon was first described and named by C. Faust in 1947 as a symptom of the bilateral region of the parieto-occipital sulcus after a through and through bullet wound of this region. Afterwards, when the concerned person stared at a truck for a while the truck seemed to decompose into its motor, chassis, driver cab and the person could only focus on one of these parts until he shortly closed his eyes or looked away which reset the shape to the complete truck again.
The characteristic of orthographic satiation as opposed to semantic satiation is that meaning remains intact. It was suggested that this is different from semantic satiation and from the stimulus familiarization effect because orthographic satiation occurs after the perceivers have access to lexical meaning.