The Analysis Following Resized Visual Stimuli Influence On Auditory Intensity Perception

Human beings achieve information from different sensory systems. Interactions between sensory systems can offer accuracy and completeness benefits for the perception. Previous studies have reported the supramodal interactions in different sensory modalities. These interactions also occur between visual system and auditory system.The aim of this thesis is to investigate the influences of spatially changing visual stimuli on the auditory intensity perception and the audiovisual temporal interactions by behavioral and event-related potentials (ERP) analysis. 61 subjects were required to judge the sound level companied with phase-locked visual stimulus. The behavior results confirmed that resized visual stimulation alters the sound intensity perception. Moreover, this audiovisual interaction involves with the inter-stimulus-interval (ISI). The analysis of subjects' electrophysiological data demonstrated that the amplitudes of ERP differential waveforms were enhanced in the components of ND190 and ND210. The amplitude of P50 after the second stimuli onset under the 170ms ISI condition was larger than that of under the 680ms ISI. ERP results provide the neural level evidence for this audiovisual interaction. The methods and results of this research provide the theory references for further investigations.Based on the previous studies, this thesis researched the influence of visual stimulus on the auditory intensity perception. The main researches and innovations are stated as follows:Firstly, the influence of visual stimulus on the auditory intensity perception has not been researched before this paper. Previous studies of audiovisual interaction mostly focus on either spatial or temporal domain. This research designed the experiment modes for testing the audiovisual effect between resized visual stimulation and the sound intensity perception and expanded the research field to intensity domain. The visual stimuli are resized circles in synchronization with monotone auditory stimuli.Secondly, this research novel applied the differential waveforms between unimodal and supramodal on visual influences on auditory intensity perception analysis. Previous literatures have suggested that sound did alter the visual evoked potentials in human. This thesis applied this general method to analyze the differential waveforms from central cortex and temporal cortex when the auditory illusion evoked by visual stimuli. These results can discover the neural mechanism behind audiovisual interaction.Finally, this thesis novel researched the influence of ISI on resized visual stimuli alters the sound intensity perception. This thesis analyzes the subjects' behavioral data under different ISI. The electrophysiological data were also investigated in order to reveal the neural mechanism.