Attentional Bias for the Left Visual Field in Ambiguous Necker Cube Processing

Abstract

There is a view that people better react to the stimuli presented in their left visual field (LVF) due to the right lateralization of the ventral attentional network (VAN). Previous studies used color-deviant stimuli and reported LVF bias for a bottom-up attentional component. Here we examined this effect for ambiguous stimuli, Necker cubes whose processing requires bottom-up and top-down attention. We instructed subjects to report cube’s orientation, left or right, while manipulated their ambiguity. In line with other works, we suggested that ambiguity enhanced reliance on the top-down mechanisms. For low ambiguity, subjects responded faster to the left-oriented cubes. EEG power increased in the right temporoparietal junction (TPJ) for 0.3 s post-stimulus onset. For high ambiguity, we found no difference in response time and EEG power. These results may evidence VAN activation when processing the bottom-up stimulus features. The eye-tracking confirmed that subjects focused on the center of the stimulus. We hypothesized that they used peripheral vision to acquire sensory information. Therefore, the LVF attentional bias might influence the evidence accumulation process. Our results support the bottom-up attentional bias to the left visual field and provide evidence for the vital role of right TPJ in controlling bottom-up attention.