Ecologically valid defocus blur contributes to avoidance of interocular suppression in half-occluded zones

In this study, the effect of defocus blur on the avoidance of interocular suppression in half-occluded zones, which are the monocular zones formed by occlusion, was examined. Six human adults observed a pair of colored random-dot stereograms, and the cumulative time of disappearance of the half-occluded zones was measured. There were three defocus blur conditions (blurry-background, blurry-occluder, and nonblur) and two fixation conditions (fixation-front and fixation-back). The author found that the cumulative time of disappearance was shorter under the blurrybackground condition of the fixation-front condition and under the blurry-occluder condition of the fixation-back condition than under the other conditions. These results indicate that ecologically valid defocus blur contributes to the avoidance of interocular suppression in the half-occluded zones.