title: From body form to biological motion: the apparent velocity of human movement biases subjective time.
abstract: In two experiments, we investigated time perception during apparent biological motion. Pictures of initial, intermediate, and final positions of a single movement were presented, with interstimulus intervals that were constant within trials but varied across trials. Movement paths were manipulated by changing the sequential order of body postures. Increasing the path length produced an increase in perceived movement velocity. To produce an implicit measure of apparent movement dynamics, we also asked participants to judge the duration of a frame surrounding the stimuli. Longer paths with higher apparent movement velocity produced shorter perceived durations. This temporal bias was attenuated for nonbody (Experiment 1) and inverted-body (Experiment 2) control stimuli. As an explanation for these findings, we propose an automatic top-down mechanism of biological-motion perception that binds successive body postures into a continuous perception of movement. We show that this mechanism is associated with velocity-dependent temporal compression. Furthermore, this mechanism operates on-line, bridging the intervals between static stimuli, and is specific to configural processing of body form.
authors.affiliation: 1Institute of Cognitive Neuroscience, University College London, UK. g.orgs@ucl.ac.uk
authors.forename: Guido
authors.initials: G
authors.lastname: Orgs
authors.forename: Sven
authors.initials: S
authors.lastname: Bestmann
authors.forename: Friederike
authors.initials: F
authors.lastname: Schuur
authors.forename: Patrick
authors.initials: P
authors.lastname: Haggard
mesh_terms: D000328:Adult; D005260:Female; D006801:Humans; D007600:Judgment / Q000502:physiology; D007699:Kinesthesis / Q000502:physiology; D008297:Male; D009068:Movement / Q000502:physiology; D010775:Photic Stimulation; D013997:Time Factors; D013998:Time Perception