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.

Multiple channels of visual time perception

“…Different clocks might exist not only for different sensory modalities [91], but they might also be specifically selected according to planned actions or movements [77,92]. Having a distributed network of adaptable local mechanisms to process temporal information might be useful for, at least, two reasons: first, to reconstruct a unified account of a fragmented perceptual experience [93,94], and, second, for stimuli of different modalities as well as for different objects in the visual scene, to extract not only their static features (such as size, shape, color, position), but also to have specific information on their temporal properties (such as knowing how rapidly they change).…”