What the â Moonwalkâ Illusion Reveals about the Perception of Relative Depth from Motion

Hdl Handle:
http://hdl.handle.net/10675.2/745
Title:
What the â Moonwalkâ Illusion Reveals about the Perception of Relative Depth from Motion
Authors:
Kromrey, Sarah; Bart, Evgeniy; Hegéd, Jay
Abstract:
When one visual object moves behind another, the object farther from the viewer is progressively occluded and/or disoccluded by the nearer object. For nearly half a century, this dynamic occlusion cue has beenthought to be sufficient by itself for determining the relative depth of the two objects. This view is consistent with the self-evident geometric fact that the surface undergoing dynamic occlusion is always farther from the viewer than the occluding surface. Here we use a contextual manipulation ofa previously known motion illusion, which we refer to as theâ Moonwalkâ illusion, to demonstrate that the visual system cannot determine relative depth from dynamic occlusion alone. Indeed, in the Moonwalk illusion, human observers perceive a relative depth contrary to the dynamic occlusion cue. However, the perception of the expected relative depth is restored by contextual manipulations unrelated to dynamic occlusion. On the other hand, we show that an Ideal Observer can determine using dynamic occlusion alone in the same Moonwalk stimuli, indicating that the dynamic occlusion cue is, in principle, sufficient for determining relative depth. Our results indicate that in order to correctly perceive relative depth from dynamic occlusion, the human brain, unlike the Ideal Observer, needs additionalsegmentation information that delineate the occluder from the occluded object. Thus, neural mechanisms of object segmentation must, in addition to motion mechanisms that extract information about relative depth, play a crucial role in the perception of relative depth from motion.
Citation:
PLoS One. 2011 Jun 22; 6(6):e20951
Issue Date:
22-Jun-2011
URI:
http://hdl.handle.net/10675.2/745
DOI:
10.1371/journal.pone.0020951
PubMed ID:
21731635
PubMed Central ID:
PMC3120826
Type:
Article
ISSN:
1932-6203
Appears in Collections:
Brain & Behavior Discovery Institute: Faculty Research and Presentations

Full metadata record

DC FieldValue Language
dc.contributor.authorKromrey, Sarahen_US
dc.contributor.authorBart, Evgeniyen_US
dc.contributor.authorHegéd, Jayen_US
dc.date.accessioned2012-10-26T20:27:55Z-
dc.date.available2012-10-26T20:27:55Z-
dc.date.issued2011-06-22en_US
dc.identifier.citationPLoS One. 2011 Jun 22; 6(6):e20951en_US
dc.identifier.issn1932-6203en_US
dc.identifier.pmid21731635en_US
dc.identifier.doi10.1371/journal.pone.0020951en_US
dc.identifier.urihttp://hdl.handle.net/10675.2/745-
dc.description.abstractWhen one visual object moves behind another, the object farther from the viewer is progressively occluded and/or disoccluded by the nearer object. For nearly half a century, this dynamic occlusion cue has beenthought to be sufficient by itself for determining the relative depth of the two objects. This view is consistent with the self-evident geometric fact that the surface undergoing dynamic occlusion is always farther from the viewer than the occluding surface. Here we use a contextual manipulation ofa previously known motion illusion, which we refer to as theâ Moonwalkâ illusion, to demonstrate that the visual system cannot determine relative depth from dynamic occlusion alone. Indeed, in the Moonwalk illusion, human observers perceive a relative depth contrary to the dynamic occlusion cue. However, the perception of the expected relative depth is restored by contextual manipulations unrelated to dynamic occlusion. On the other hand, we show that an Ideal Observer can determine using dynamic occlusion alone in the same Moonwalk stimuli, indicating that the dynamic occlusion cue is, in principle, sufficient for determining relative depth. Our results indicate that in order to correctly perceive relative depth from dynamic occlusion, the human brain, unlike the Ideal Observer, needs additionalsegmentation information that delineate the occluder from the occluded object. Thus, neural mechanisms of object segmentation must, in addition to motion mechanisms that extract information about relative depth, play a crucial role in the perception of relative depth from motion.en_US
dc.rightsKromrey et al. This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.en_US
dc.subjectResearch Articleen_US
dc.subjectBiologyen_US
dc.subjectComputational Biologyen_US
dc.subjectComputational Neuroscienceen_US
dc.subjectSensory Systemsen_US
dc.subjectNeuroscienceen_US
dc.subjectCognitive Neuroscienceen_US
dc.subjectCognitionen_US
dc.subjectComputational Neuroscienceen_US
dc.subjectSensory Systemsen_US
dc.subjectSensory Systemsen_US
dc.subjectVisual Systemen_US
dc.subjectSensory Perceptionen_US
dc.subjectComputer Scienceen_US
dc.subjectComputing Methodsen_US
dc.subjectComputer Inferencingen_US
dc.subjectMedicineen_US
dc.subjectAnatomy and Physiologyen_US
dc.subjectSensory Systemsen_US
dc.subjectMental Healthen_US
dc.subjectPsychologyen_US
dc.subjectCognitive Psychologyen_US
dc.subjectSensory Perceptionen_US
dc.subjectSocial and Behavioral Sciencesen_US
dc.subjectPsychologyen_US
dc.subjectCognitive Psychologyen_US
dc.subjectExperimental Psychologyen_US
dc.subjectPsychometricsen_US
dc.subjectPsychophysicsen_US
dc.subjectSensory Perceptionen_US
dc.titleWhat the â Moonwalkâ Illusion Reveals about the Perception of Relative Depth from Motionen_US
dc.typeArticleen_US
dc.identifier.pmcidPMC3120826en_US
dc.contributor.corporatenameBrain & Behavior Discovery Institute-
dc.contributor.corporatenameVision Discovery Institute-
dc.contributor.corporatenameDepartment of Ophthalmology-

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