Visual engagement modulates cortical criticality and auditory target detection thresholds in noisy soundscapes

The widely held assumption that closing eyes enhances auditory sensitivity has been supported by auditory attention experiments. However, the visual effects on auditory thresholds of detecting target sounds masked by noise remain unexplored. We investigated the participants' detection thresholds (n = 25) of target sounds (canoe paddle, drum, lark chirping, train, and keyboard) masked by 70 dB(A) pink noise under four visual conditions (eyes closed, eyes open with blank board, static visual stimulation, and dynamic visual stimulation). Taking blank visual stimulation as the baseline, eye closure elevated detection thresholds by 1.32 dB on average, whereas dynamic and static relevant visual stimulation lowered them by 2.98 and 1.60 dB, respectively, contrary to conventional belief. Electroencephalogram recordings (n = 27) demonstrated avalanche critical index reduction of 22.3%-45.2% across five auditory stimuli under eye closure compared with blank stimulation, revealing that non-visual states preferentially stabilize neural dynamics near critical states. We propose a unified auditory-cortical framework based on the brain dynamics theory to explain both the enhanced auditory target detection during visual engagement in noisy environments and optimized auditory segregation via visual disengagement in quiet settings, advancing our understanding of visual effects on auditory perception in complex noisy soundscapes.