In 1875, the physiologistSigmund Exner showed that, under the right conditions, people will see two quick, spatially separated but stationary electrical sparks as a single light moving from place to place, while quicker flashes were interpreted as motion between two stationary lights. Exner argued that the impression of the moving light was a perception (from a mental process) of the motion between the stationary lights as pure sense.[1] This is an explanation of the optical illusion of illusory motion known as the beta movement. The illusion of motion caused by animation and film is sometimes believed to rely on beta movement, as an alternative to the older explanation known as persistence of vision.[2]
^Kahle, Paul. “The Arabic Shadow Play in Egypt.” The Journal of the Royal Asiatic Society of Great Britain and Ireland, no. 1, 1940, pp. 21–34. JSTOR, http://www.jstor.org/stable/25221591. Accessed 10 Mar. 2023.
^Milwright, Marcus. “ON THE DATE OF PAUL KAHLE’S EGYPTIAN SHADOW PUPPETS.” Muqarnas, vol. 28, 2011, pp. 43–68. JSTOR website Retrieved 10 Mar. 2023.