| Speed and direction of locally-paired dot patterns. | |
| | |
MedLine Citation:
|
PMID: 10878273 Owner: NLM Status: MEDLINE |
Abstract/OtherAbstract:
|
Phenomenal transparency in random-dot kinematograms is abolished when two motion directions are 'locally-balanced' by pairing limited-lifetime dots at each location [Qian, Andersen and Adelson (1994). Journal of Neuroscience, 14, 7357-7366]. Qian et al. also report that locally-paired stimuli appear as directionless flicker when the paired dots differ in their directions by 90 degrees or more. They attribute this to local inhibition between motion detectors more than 45 degrees apart. We investigated perceived motion in such displays, by requiring subjects to make direction and speed judgements with locally-paired stimuli containing two directions 60, 90 or 120 degrees apart. Subjects perceived coherent motion in these displays and made reliable direction judgements, indicating that the two motions are combined rather than interfering destructively. Our results show that the judged motion of locally-paired stimuli is in the vector-average direction of the two components. This vector-averaging rule also applies when the two sets of component dots differ in their velocity. Similarly, speed judgements comply with a vector-averaging rule for a range of speeds as well as for mixed-speed stimuli. These results suggest that the abolition of transparency does not necessarily imply abolition of a global motion percept. The local interaction abolishing transparency is not exclusively inhibitory, at least for directions up to 120 degrees apart, but generates a vector combination of the superimposed motions. |
| | |
Authors:
|
W Curran; O J Braddick |
Related Documents
:
|
19761323 - Assessing direction-specific adaptation using the steady-state visual evoked potential:... 18308363 - Combining direction and speed for the localisation of visual motion defined contours. 14686503 - Three-dimensional spatial grouping affects estimates of the illuminant. |
Publication Detail:
|
Type: Journal Article; Research Support, Non-U.S. Gov't |
Journal Detail:
|
Title: Vision research Volume: 40 ISSN: 0042-6989 ISO Abbreviation: Vision Res. Publication Date: 2000 |
Date Detail:
|
Created Date: 2000-08-28 Completed Date: 2000-08-28 Revised Date: 2006-11-15 |
Medline Journal Info:
|
Nlm Unique ID: 0417402 Medline TA: Vision Res Country: ENGLAND |
Other Details:
|
Languages: eng Pagination: 2115-24 Citation Subset: IM; S |
Affiliation:
|
Visual Development Unit, Department of Psychology, University College London, Gower Street, WC1E 6BT, London, UK. w.curran@ucl.ac.uk |
Export Citation:
|
APA/MLA Format Download EndNote Download BibTex |
| MeSH Terms | |
Descriptor/Qualifier:
|
Humans Mathematics Motion Perception / physiology* Photic Stimulation / methods* |
From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine
Previous Document: Probability summation for multiple patches of luminance modulation.
Next Document: What limits the contribution of second-order motion to the perception of surface shape?