| Rotating dotted ellipses: motion perception driven by grouped figural rather than local dot motion signals. | |
| | |
MedLine Citation:
|
PMID: 17548102 Owner: NLM Status: MEDLINE |
Abstract/OtherAbstract:
|
Unlike the motion of a continuous contour, the motion of a single dot is unambiguous and immune to the aperture problem. Here we exploit this fact to explore the conditions under which unambiguous local motion signals are used to drive global percepts of an ellipse undergoing rotation. In previous work, we have shown that a thin, high aspect ratio ellipse will appear to rotate faster than a lower aspect ratio ellipse even when the two in fact rotate at the same angular velocity [Caplovitz, G. P., Hsieh, P. -J., & Tse, P. U. (2006) Mechanisms underlying the perceived angular velocity of a rigidly rotating object. Vision Research, 46(18), 2877-2893]. In this study we examined the perceived speed of rotation of ellipses defined by a virtual contour made up of evenly spaced dots. RESULTS: Ellipses defined by closely spaced dots exhibit the speed illusion observed with continuous contours. That is, thin dotted ellipses appear to rotate faster than fat dotted ellipses when both rotate at the same angular velocity. This illusion is not observed if the dots defining the ellipse are spaced too widely apart. A control experiment ruled out low spatial frequency "blurring" as the source of the illusory percept. CONCLUSION: Even in the presence of local motion signals that are immune to the aperture problem, the global percept of an ellipse undergoing rotation can be driven by potentially ambiguous motion signals arising from the non-local form of the grouped ellipse itself. Here motion perception is driven by emergent motion signals such as those of virtual contours constructed by grouping procedures. Neither these contours nor their emergent motion signals are present in the image. |
| | |
Authors:
|
G P Caplovitz; P U Tse |
Publication Detail:
|
Type: Journal Article; Research Support, N.I.H., Extramural; Research Support, U.S. Gov't, Non-P.H.S. Date: 2007-06-04 |
Journal Detail:
|
Title: Vision research Volume: 47 ISSN: 0042-6989 ISO Abbreviation: Vision Res. Publication Date: 2007 Jul |
Date Detail:
|
Created Date: 2007-06-19 Completed Date: 2007-08-14 Revised Date: 2007-12-03 |
Medline Journal Info:
|
Nlm Unique ID: 0417402 Medline TA: Vision Res Country: England |
Other Details:
|
Languages: eng Pagination: 1979-91 Citation Subset: IM |
Affiliation:
|
Department of Psychological and Brain Sciences, Dartmouth College, Hanover, NH 03755, USA. Gideon.Caplovitz@dartmouth.edu |
Export Citation:
|
APA/MLA Format Download EndNote Download BibTex |
| MeSH Terms | |
Descriptor/Qualifier:
|
Form Perception* Humans Motion Perception* Optical Illusions* Photic Stimulation / methods Psychophysics Rotation |
| Grant Support | |
ID/Acronym/Agency:
|
R03 MH0609660-01/MH/NIMH NIH HHS |
From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine
Previous Document: Purification and properties of hyaluronidase from Hippasa partita (funnel web spider) venom gland ex...
Next Document: Influence of dissolved organic matter on estrone removal by NF membranes and the role of their struc...