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| Volume 4, Number 3, Article 6, Pages 196-202 |
doi:10.1167/4.3.6 |
http://journalofvision.org/4/3/6/ |
ISSN 1534-7362 |
Determinants of visual awareness following interruptions during rivalry
Joel Pearson |
Color, Form & Motion Lab, Visual Perception Unit, School of Psychology, The University of Sydney, NSW 2006, Australia |
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Colin W. G. Clifford |
Color, Form & Motion Lab, Visual Perception Unit, School of Psychology, The University of Sydney, NSW 2006, Australia |
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Abstract
The inability of the human visual system to fuse
dissimilar patterns in corresponding regions of the two eyes results in
stochastic alternation of perceptual dominance between the two patterns:
rivalry. When rivalrous stimuli are presented intermittently their perception is
stabilized (Leopold, Wilke, Maier, & Logothetis, 2002). This stability indicates the operation of
some kind of perceptual memory across interruptions in stimulation. Here we
examined the contents of this perceptual memory to quantify the relative
contributions of different sources of information: eye-of-origin, orientation,
and color. Stimuli were intermittently presented and, during each blank
interruption, we swapped either the color, orientation, or eye of presentation
of the gratings. Comparing the percepts reported before and after each
interruption allowed us to establish what aspects of perception remained stable.
During conventional binocular rivalry, the eye in which the stimulus was
presented remained stable across 74% of interruptions. Stimulus color and
orientation also had weaker significant effects. When eye-of-origin information was eliminated by alternating the patterns rapidly between the two eyes,
stimulus color remained stable across 86% of interruptions. Stimulus orientation
again had a weaker but significant effect. These results demonstrate that the
mechanisms mediating perceptual stability across interruptions in rivalry can
operate at both monocular and binocular levels, much like the mechanisms
operating during continuous viewing of rivalrous stimuli. On the basis of this
similarity, we speculate that perceptual memory across interruptions in rivalry
may involve the same neural representations as visual competition during
rivalry. If this is the case, the use of intermittent stimulation in rivalry
might permit the investigation of aspects of the mechanisms underlying visual
competition that remain hidden during continuous presentation.
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