Oakyoon Cha¹; ¹Department of Psychology, Sogang University

Under binocular rivalry, two incompatible images compete for awareness, producing perceptual alternations. Rivalrous perception consists of periods of exclusive dominance, where only one image is consciously visible, and mixed dominance, where a dynamic patchwork of the two images is experienced. Mixed dominance can lead either to a switch, in which perception progresses to the other image, or to a return, in which perception briefly becomes patchwork-like but subsequently reverts to the previous image. To investigate the factors that determine switch versus return transitions, I modeled the durations of the two mixed-dominance types using separate Linear Ballistic Accumulator (LBA) models. Drift rates did not differ between models, suggesting that the state at exclusive-dominance breakdown does not bias which transition occurs. In contrast, both the decision boundary and variability of starting point were larger for returns than for switches. These results support the interpretation that the “distance to travel” in perceptual space governs mixed-dominance dynamics. Return events may reflect incomplete progress toward the alternative percept. This account predicts that the boundary for returns should be less than twice that for switches, because failed progress would revert to the original percept. Consistent with this prediction, this pattern was observed for all 10 participants, suggesting that switches and returns may be captured within a single model incorporating a failure-to-switch component. Altogether, these findings provide a mechanistic account of mixed-dominance trajectories in binocular rivalry that can be captured within the LBA framework.

Acknowledgements: This work was supported by the National Research Foundation of Korea (NRF) grant funded by the Korean government (Ministry of Science and ICT) (No. RS-2023-00211668) and by the Sogang University Research Grant of 2025 (202510012.01).