Abstract
It is widely believed that binocular rivalry is resolved by top-down influences that bias a momentary selection towards either of the two rival images. In our previous study, we observed a pattern of results supporting such a top-down account, where the rivalry appears to be resolved by information held in visual working memory (VWM). However, recent neural findings suggest that binocular rivalry occurs during the early visual processes of feedforward sweeps, presuming a minimal role of top-down influences. In this study, we tested the alternative bottom-up account by addressing whether the rivalry sensation is distinct, even under the influence from VWM. In the experiments, participants remembered the colors of 2, 4, and 6 binocularly displayed items (memory array) and then compared their colors with those in the next binocular display (test array). In half of the trials, the memory and test displays were identical (i.e., no-change), whereas the remainder were divided into three trial-types. An item in the test display mismatched the memory array by (1) binocular mismatches (i.e., standard change), (2) a monocular mismatch (i.e., rivalry), or (3) a monocular mismatch with the other binocular test item missing (i.e., blank-rivalry). The participants also categorized each trial based on distinct sensation upon the test display. The results demonstrated that both the standard and blank-rivalry trials yielded patterns of a setsize effect, apparently derived from the memory accuracy decline along the setsizes, while the rivalry trials yielded a relative lack of the setsize effect. Moreover, trial categorization responses revealed that the participants were explicitly able to tell the sensation of the rivalry from the standard change or the blank-rivalry occurrence. These results suggest that binocular rivalry can occur from rival stimuli per se, while resisting top-down influences from VWM, and support bottom-up account for rivalry occurrence and its phenomenological consequence.
Meeting abstract presented at VSS 2014