Cite as:
Pas S F t, Paffen C L E, Kanai R, van der Smagt M J, Verstraten F A J, 2003, "Similar contrast effects for motion and colour during binocular rivalry" Perception 32 ECVP Abstract Supplement

Similar contrast effects for motion and colour during binocular rivalry

S F te Pas, C L E Paffen, R Kanai, M J van der Smagt, F A J Verstraten

Two dichoptically presented, dissimilar stimuli will engage in binocular rivalry. Which of the two stimuli dominates the percept can be affected by a surrounding stimulus, as has been shown by Fukuda and Blake for orientation (1992 Journal of Experimental Psychology: Human Perception and Performance 18 362 - 370). To investigate whether this phenomenon can be generalised, we now extend the experiments to the motion and the colour domain. Two discs containing a leftward moving grating in one eye and a rightward moving grating in the other eye were presented at the centre of fixation. The discs could be surrounded by an annulus that contained motion in the same direction as one of the two discs. The annulus was presented to only one of the two eyes. The direction of motion of the annulus could either be that of the disc that was presented to the same eye, or that of the disc that was presented to the other eye. Observers continuously indicated the perceived direction of motion of the central disc. We found that the disc that contained the motion direction opposite to the surround was more dominant, irrespective of its positioning (same or different eye as compared to the annulus). We ran the same experiment in the colour domain; that is, instead of leftward and rightward moving gratings, we now had a red disc in one eye and a green disc in the other eye. The discs as well as surrounding annuli were made isoluminant relative to a yellow background. The disc with the colour opposite to the surrounding annulus was more dominant, irrespective of its positioning. We have observed similar contrast effects during rivalry in both colour and motion. Moreover, these contrast effects occurred irrespective of the position of the surround, suggesting that the mechanism behind these contrast effects is at least partly binocular.

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