Semantic Suppression in Figure-Ground Perception and Binocular Rivalry
PublisherThe University of Arizona.
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AbstractFigure-ground segregation occurs when one of two regions sharing a border is perceived as a shaped entity (a figure) and the other is perceived as a shapeless background to the figure. The mechanism of figure-ground perception is inhibitory competition. Peterson and Skow (2008) showed that a familiar configuration that loses the competition for figural status is not perceived consciously and is suppressed, at least at the level of categorical shape. A remaining question is whether the semantics of the familiar configuration are also accessed and suppressed. The present study investigates this question through binocular rivalry. Binocular rivalry occurs when separate images are simultaneously presented to the left and right eyes. Typically one dominates at any given moment, and awareness alternates back and forth between these two images. The image that is not perceived is suppressed (Wheatstone, 1838). The present experiments investigated how the suppression in figure-ground perception and the suppression in binocular rivalry interact. In one eye, subjects viewed a silhouette that initially dominated because a dynamic, colorful pattern was presented within the confines of the figure. In the other eye, participants viewed a word string either a word that named a familiar configuration or a non-word; the letter string was initially suppressed. Experiment 1 explored whether the time required for the letter string to reach awareness between a silhouette that had a hidden, familiar configuration on the ground side or a silhouette with a novel configuration on the ground. Experiment 2 observed the time required to make a lexical decision once the letter string arrived to awareness. Both experiments failed to yield evidence for an interaction between figure-ground and binocular rivalry suppression. This suggests that during binocular rivalry, a shape suppressed by figure-ground competition fails to interact with a word corresponding to the suppressed shape.
Degree ProgramHonors College