The Anorthoscopic Short Story

Abstract

The 19th century researcher and theorist of perception Hermann von Helmholtz employed a device called an anorthoscope to investigate form perception. It consisted of two discs mounted one behind the other, each capable of rotating at varying speeds and in different directions. On the first disc was a series of slits through which a figure on the second was successively revealed. Similar in structure to a phenakistiscope and other devices of the time designed to create the illusion of movement by exploiting the phenomenon of retinal persist­ ence, it was used by Helmholtz to determine the processes involved in the perception and recognition of contours and forms. He discovered that, under the right conditions, it was possible for an observer to recognize the underlying form despite the fact that at any one time only a very small part of it was visible in the area of the slit. This is known as the anorthoscopic effect'. In the 1960s, there was a resurgence of interest in anorthoscopic vision and researchers in visual perception devised more sophisticated methods of investigating the phenomenon. There is still some disagreement over how to account for the anortho­ scopic effect one fairly recent study can only conclude that it cannot be explained as a direct outcome of the physiological processing of contours stimulating the retina and that therefore 'the perception of form is a process much closer to the cognitive level than has heretofore been recognized' (Rock, 1983: 191). In an essay on Die Distanz, a piece by the video artist Marcel Odenbach who uses a variation of the anorthoscopic slit in this work, Paul Virilio argues that the anorthoscopic aesthetic approaches the condition of a perceptionless perception in that it attempts to reduce the visual field to the smallest possible unit: