phi phenomenon

noun

: apparent motion resulting from an orderly sequence of stimuli (such as lights flashed in rapid succession a short distance apart on a sign) without any actual motion being presented to the eye

Examples of phi phenomenon in a Sentence

Recent Examples on the Web

The brain then fills in the gaps between still images viewed in rapid succession and perceives this as movement, an illusion that early-20th-century psychologists named the phi phenomenon. —Charlotte Hu, Scientific American, 31 Oct. 2024

Word History

Etymology

translation of German φ-Phänomen

Note: The term was introduced by the psychologist Max Wertheimer (1880-1943, born in Prague, Austria-Hungary, in the U.S. from 1933) in "Experimentelle Studien über das Sehen von Bewegung," Zeitschrift für Psychologie und Physiologie der Sinnesorgane, 1. Abteilung, Zeitschrift für Psychologie, Band 61, Heft 1 (April, 1912), pp. 161-265.

First Known Use

circa 1928, in the meaning defined above

Medical Definition

phi phenomenon

noun

ˈfī- 

: apparent motion resulting from an orderly sequence of stimuli (as lights flashed in rapid succession a short distance apart on a sign) without any actual motion being presented to the eye compare apparent motion