Mental Imagery Modulates Bistable Perception in a Modality-Specific Manner

Multimodal approaches are essential for understanding the mechanisms and constraints of mental imagery, yet few studies have directly compared its perceptual effects across sensory systems. This study explored how mental imagery influences bistable perception in vision and audition by comparing imagery-based and sensory-based priming in binocular rivalry and auditory streaming. In an initial analysis, we investigated the time course of priming effects, finding that strong early dominance of the integrated percept in auditory streaming masked any influence of priming. In contrast, binocular rivalry showed clear and asymmetric priming effects within the first few seconds, with imagery and sensory cues both biasing perceptual onset. Specifically, rightward motion imagery more effectively enhanced dominance than leftward imagery suppressed it, potentially reflecting habitual scanning tendencies. While priming significantly influenced the type of initial percept in binocular rivalry, no such effect was found in auditory streaming. Furthermore, priming affected the duration of the first percept in vision, but not in audition, suggesting that imagery modulates both perceptual selection and early perceptual persistence in the visual domain. Notably, the strength of imagery priming in vision correlated with self-reported imagery vividness, supporting the functional relevance of individual differences in mental imagery. These findings indicate that imagery can bias visual perception but may have limited influence in audition under current task constraints, likely due to modality-specific dynamics and early integration biases. This study provides behavioural evidence for the modality-specific impact of mental imagery and underscores the value of cross-modal designs in understanding how internal representations shape conscious perception.