Aerospace Medicine Technical Reports

FAA Office of Aerospace Medicine
Civil Aerospace Medical Institute


Report No: DOT/FAA/AM-68/10

Title and Subtitle: The spiral aftereffect: Influence of stimulus size and viewing distance on the duration of illusory motion

Report Date: May 1968

Authors: Collins WE, Schroeder DJ

Abstract: The study examined some effects of stimulus size and distance on the persistence of one type of illusory motion, viz., the spiral aftereffect (SAE). Duration of SAE was investigated with stimuli of 2, 4, 8, 12, and 16 inches in diameter. The distance between the observers and the rotating spirals was varied to produce visual angles between 1 deg. 12 min. and 18 deg. 56 min. of arc. Data indicate that the duration of illusory motion reaches peak values between approximately 2 deg. -4 deg. of visual angle.

Key Words: Illusions, vision, afterimages, motion, stimulation, aviation medicine

No. of Pages: 8

Last updated: Friday, June 1, 2012