the holistically perceived form of an object revealed over time through a narrow slit aperture. It is distinct from ordinary object perception in that the perceived object arises from the temporal integration of visual information derived from the same retinotopic area (i.e., there is no spatially extended retinotopic image). Also called slit viewing. See anorthoscope. [first reported in 1862 by German astrophysicist Johann Karl Friedrich Zöllner (1834–1882)]