noun
phi phenomenon
An optical illusion of apparent motion caused by successive presentation of stationary stimuli; a key concept in Gestalt psychology.
ファイ現象は、映画やアニメーションの基本原理の一つです。
The phi phenomenon is one of the basic principles behind movies and animation.
Beta movement is a related but distinct illusion of apparent motion where a single object seems to move, whereas the phi phenomenon involves the perception of pure motion without a moving object.
From English 'phi phenomenon', coined by psychologist Max Wertheimer. The term uses the Greek letter phi (φ) to denote the illusory motion perceived.