TY - JOUR

T1 - The contribution of stereopsis in Emmert's law

AU - Millard, Amy Siobhan

AU - Sperandio, Irene

AU - Chouinard, Philippe A

PY - 2020/4

Y1 - 2020/4

N2 - Size constancy is the ability to perceive objects as remaining constant in size regardless of their distance from the observer. Emmert's law demonstrates that viewing distance determines the perceived size of afterimages according to the amount of depth cues that are available. Using an afterimage paradigm, we examined to what extent removing stereopsis and other depth cues affects size-distance scaling. Thirty participants 'projected' afterimages onto a surface presented at different distances under binocular, monocular, and eyes-closed conditions. The perceived size of the afterimages closely followed the size-distance scaling predictions made by Emmert's law under binocular testing conditions, when all depth cues were available. In contrast, monocular testing decreased adherence to Emmert's law, while the eyes-closed condition resulted in a greater breakdown of size-distance scaling. Because we used an afterimage paradigm, this study provides the first demonstration of how perceived size is modulated by the availability of depth cues under conditions with a constant retinal image stimulus.

AB - Size constancy is the ability to perceive objects as remaining constant in size regardless of their distance from the observer. Emmert's law demonstrates that viewing distance determines the perceived size of afterimages according to the amount of depth cues that are available. Using an afterimage paradigm, we examined to what extent removing stereopsis and other depth cues affects size-distance scaling. Thirty participants 'projected' afterimages onto a surface presented at different distances under binocular, monocular, and eyes-closed conditions. The perceived size of the afterimages closely followed the size-distance scaling predictions made by Emmert's law under binocular testing conditions, when all depth cues were available. In contrast, monocular testing decreased adherence to Emmert's law, while the eyes-closed condition resulted in a greater breakdown of size-distance scaling. Because we used an afterimage paradigm, this study provides the first demonstration of how perceived size is modulated by the availability of depth cues under conditions with a constant retinal image stimulus.

KW - ACCOMMODATION

KW - ADAPTATION

KW - AFTERIMAGES

KW - ATTENTION

KW - Afterimages

KW - CONSCIOUSNESS

KW - CONVERGENCE

KW - Emmert's law

KW - PERCEPTION

KW - SIZE-CONSTANCY

KW - Size constancy

KW - Size perception

KW - VERGENCE

KW - VISUAL SIZE

KW - Vision

UR - http://www.scopus.com/inward/record.url?scp=85082967557&partnerID=8YFLogxK

U2 - 10.1007/s00221-020-05747-5

DO - 10.1007/s00221-020-05747-5

M3 - Article

C2 - 32215670

VL - 238

SP - 1061

EP - 1072

JO - Experimental Brain Research

JF - Experimental Brain Research

SN - 0014-4819

IS - 4

ER -