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The visual processing of motion-defined transparency

Curran, William and Hibbard, Paul B and Johnston, Alan (2007) 'The visual processing of motion-defined transparency.' Proceedings of the Royal Society B: Biological Sciences, 274 (1613). pp. 1049-1057. ISSN 0962-8452

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<jats:p>Our understanding of how the visual system processes motion transparency, the phenomenon by which multiple directions of motion are perceived to coexist in the same spatial region, has grown considerably in the past decade. There is compelling evidence that the process is driven by global-motion mechanisms. Consequently, although transparently moving surfaces are readily segmented over an extended space, the visual system cannot separate two motion signals that coexist in the same local region. A related issue is whether the visual system can detect transparently moving surfaces simultaneously or whether the component signals encounter a serial ‘bottleneck’ during their processing. Our initial results show that, at sufficiently short stimulus durations, observers cannot accurately detect two superimposed directions; yet they have no difficulty in detecting one pattern direction in noise, supporting the serial-bottleneck scenario. However, in a second experiment, the difference in performance between the two tasks disappears when the component patterns are segregated. This discrepancy between the processing of transparent and non-overlapping patterns may be a consequence of suppressed activity of global-motion mechanisms when the transparent surfaces are presented in the same depth plane. To test this explanation, we repeated our initial experiment while separating the motion components in depth. The marked improvement in performance leads us to conclude that transparent motion signals are represented simultaneously.</jats:p>

Item Type: Article
Uncontrolled Keywords: motion perception; transparency; global motion; motion integration
Subjects: B Philosophy. Psychology. Religion > BF Psychology
Divisions: Faculty of Science and Health
Faculty of Science and Health > Psychology, Department of
SWORD Depositor: Elements
Depositing User: Elements
Date Deposited: 30 Jan 2015 16:23
Last Modified: 18 Aug 2022 13:04

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