title: High temporal frequency adaptation compresses time in the Flash-Lag illusion.
abstract: Previous research finds that 20 Hz temporal frequency (TF) adaptation causes a compression of perceived visual event duration. We investigate if this temporal compression affects further time-dependent percepts, implying a further functional role for duration perception mechanisms. We measure the effect of 20 Hz flicker adaptation on Flash-Lag, an illusion whereby an observer perceives a moving object displaced further along its trajectory compared to a spatially localized briefly flashed object. The illusion scales with object speed; therefore, it has a fixed temporal component. By comparing adaptation at 5 Hz and 20 Hz we show that 20 Hz TF adaptation reduces perceived Flash-Lag magnitude significantly, with no effect at 5 Hz, whereas the opposite pattern of adaptation was seen on perceived speed. There is a significant effect of 20 Hz adaptation on the perceived duration of a moving bar. This suggests that 20 Hz TF adaptation has compressed the fixed temporal component of the Flash-Lag illusion, implying the mechanism underlying duration perception also has effects on judging spatial relationships in dynamic stimuli.
authors.affiliation: Department of Psychology, Royal Holloway, University of London, Egham Hill, Egham, Surrey TW20 0EX, United Kingdom. Electronic address: Edward.Rowland.2009@live.rhul.ac.uk.
authors.forename: Edward
authors.initials: E
authors.lastname: Rowland
authors.affiliation: Department of Psychology, Royal Holloway, University of London, Egham Hill, Egham, Surrey TW20 0EX, United Kingdom. Electronic address: Szonya.Durant@rhul.ac.uk.
authors.forename: Szonya
authors.initials: S
authors.lastname: Durant
mesh_terms: D000222:Adaptation, Physiological; D000704:Analysis of Variance; D006801:Humans; D009039:Motion Perception / Q000502:physiology*; D009903:Optical Illusions / Q000502:physiology*; D010775:Photic Stimulation / Q000379:methods; D011601:Psychophysics; D011930:Reaction Time; D013998:Time Perception / Q000502:physiology*; D014796:Visual Perception / Q000502:physiology*
keywords: Motion perception; Psychophysics; Time perception; Visual illusions