Abstract
Sensory eye dominance (SED) is reduced with a push-pull perceptual learning protocol that uses exogeneous attention cueing in a binocular rivalry stimulation to force the weak eye to dominance (Ooi & He, 1999; Xu et al, 2010). A major factor triggering learning is the suppression of the strong eye (pull) as the weak eye is excited (push), rather than the attention cueing of the weak eye in itself. To support this contention, we designed two new push-pull protocols without attention cueing. Instead, we manipulated the boundary contour (BC) strength of the rivaling half-images. In the first, BC-1 push-pull protocol, an image with grating feature but no BC was presented to the strong eye. In the second, BC-2 push-pull protocol, an image with grating feature and BC was presented to the strong eye. The weak eye in both protocols received an image with very strong grating feature and BC to ensure its dominance. Each observer underwent both protocols at two parafoveal locations. We found that similar to the original push-pull protocol with attention cueing, both BC-1 and BC-2 push-pull protocols significantly reduce SED and improve stereopsis. This indicates that perceptual learning is triggered as long as the strong eye’s image is suppressed, whether by exogeneous attention cueing of the weak eye or by increasing the stimulus strength of the weak eye. Our data also reveal that the perceptual learning effect is larger in the BC-2 push-pull protocol where the strong eye’s image carried both grating feature and BC information. Thus, compared to the strong eye’s image in the BC-1 push-pull protocol that only had grating feature, this suggests that learning is more effective when there are more image attributes to suppress. Overall, this study further underscores the significance of the "pull" component in the push-pull learning protocol to effectively reduce SED.
Meeting abstract presented at VSS 2012