title: Visual reaction time and size constancy.
abstract: We carried out six experiments to find out whether simple manual reaction time (RT) to flux-equated visual stimuli of different size is modulated by size constancy or by the retinal angle subtended by the stimuli. We found that RT decreased with the increase in perceived stimulus size rather than retinal angle and that this relationship depended on the use of familiar 3-D-like stimuli and on the availability of other size-constancy cues. Thus, a stereotyped speeded motor response, such as that employed in a simple RT paradigm, is modulated by size constancy, as is the case with perceptual judgments. The present results provide original evidence on the relationship between simple RT and perception.
authors.affiliation: Department of Neurological Sciences and Vision, Physiology Section, University of Verona, 8 Strada Le Grazie, 37134 Verona, Italy.
authors.forename: Irene
authors.initials: I
authors.lastname: Sperandio
authors.forename: Silvia
authors.initials: S
authors.lastname: Savazzi
authors.forename: Richard L
authors.initials: RL
authors.lastname: Gregory
authors.forename: Carlo A
authors.initials: CA
authors.lastname: Marzi
mesh_terms: D000328:Adult; D000704:Analysis of Variance; D004215:Distance Perception / Q000502:physiology; D005260:Female; D006801:Humans; D008297:Male; D010775:Photic Stimulation; D011930:Reaction Time; D012858:Size Perception / Q000502:physiology*; D055815:Young Adult