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The contribution of stereopsis in Emmert's law

Research output: Contribution to journalArticle

Authors

  • Amy Siobhan Millard
  • Irene Sperandio
  • Philippe A Chouinard

Organisational units

Abstract

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.

Details

Original languageEnglish
Pages (from-to)1061–1072
Number of pages12
JournalExperimental Brain Research
Volume238
Issue number4
Early online date25 Mar 2020
DOIs
Publication statusPublished - Apr 2020
Peer-reviewedYes

Keywords

    Research areas

  • ACCOMMODATION, ADAPTATION, AFTERIMAGES, ATTENTION, Afterimages, CONSCIOUSNESS, CONVERGENCE, Emmert's law, PERCEPTION, SIZE-CONSTANCY, Size constancy, Size perception, VERGENCE, VISUAL SIZE, Vision

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