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 auditory streaming, an acoustic bias promoting segregation increased the likelihood of an early segregated percept, whereas an imagery priming did not. Binocular rivalry exhibited robust and asymmetric priming effects within the first few seconds, with both imagery and physical cues biasing perceptual onset. While both physical and imagery priming significantly influenced the initial percept in binocular rivalry, only physical priming affected perceptual reports in auditory streaming. 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.