The Research On Crossmodal Attention Shift In Vision And Audition

In everyday life, we encounter numerous situations in which we have to direct attention selectively to a particular perceptual modality (e.g., visual, auditory, tactile) in order to acquire information necessary for achieving our current action goals. We have to switch our attention from one sensory to another. In cue-target paradigm, the modality of the cue affected the processing of the target depending on whether they shared the same modality. Specifically, target shared same modality with the cue lead to faster detection times compared to target shared different modality with the cue. It's cue effect of modality. The cue effect of modality reflected the processing differences between the stimuli with modality shift and without modality shift.The thesis mainly concerns the crossmodal attention shift in vision and audition about characteristic, influence factors and top-down control. Two studies including five experiments were carried out.The study one discussed the characteristic and influence factors with cue-target paradigm. The experiment 1 found cue effect of modality in audition. An auditory cue facilitated the discrimination of an auditory target. While cue effect of modality don't observed on the visual target. It's probably that auditory stimuli have an automatic alerting effect while visual stimuli have an effortful alerting effect. The asymmetry of cue effect of modality in vision and audition was reported in experiment 1.Based on the experiment 1, the experiment 2 changed the task slightly to increase the participants'attention to the cues. In the experiment 2, the participants have to judge the cue's modality before the target presented. Similarly, response time to visual target followed an auditory cue was slower compared to a visual cue. It failed to found the asymmetry of cue effect of modality in vision and audition suggesting that attention enhancement to the cues may weaken or eliminate the asymmetry of cue effect of modality in vision and audition.The experiment 3 investigated the affect of cue validity and ISI (inter-stimulus interval) on crossmodal attention shift. The results found cue effect of modality in 75% validity and cue effect of modality reversal in 25% validity. The cue effect of modality time interval between cue and target was also varied. It suggested that participants can voluntarily switch attention to a sensory modality by using an informative cue. This is a top-down control, which can't be influenced by ISI. However, the cue effect of modality decreased with the ISI increasing in the non-informative cue. It suggested that top-down and bottom-up control modulated crossmodal attention shift.In study 2, two experiments were included, and the ERP (event-related potential) technology was used. Experiment 4 investigated the neural mechanism of asymmetry of crossmodal attention shift. The results found that the auditory target-evoked neural activity was modulated by modality shift in early stage, which was reflected on larger N1. There was a null effect of modality on visual target. N2, P3 and difference wave in audition was different from vision. It suggested that the asymmetry of cue effect of modality reflected on the early stage of brain processing. Vision may pay more attention to need to be attended modality while audition may pay more attention to stimulus with modality shift.Experiment 5 investigated the relative timing of neural activity during modality attention shift modulated by top-down control. Attention shift-inducing cues were compared to attention hold-inducing cues, while in both conditions participants were required to detect target that were subsequently presented simultaneously in audition and vision. There were two types of cues:visual cue and auditory cue. The results found that the human brain is capable of very rapidly identifying the difference between different types of instructions. The top-down attention shift inducing by auditory cues was affected by the initial modality. The modality of auditory cues may influence modality attention shift. While similar effect failed to found in visual cues. Visual cues could induce the top-down attention shift in early processing stage.To summarize the findings of the two studies, the conclusion was made as follows.(1) There is an asymmetry of crossmodal attention shift in audition and vision.(2) The asymmetry of crossmodal attention shift in audition and vision on electrical activity of the brain is in two aspects:processing time and processing pattern.(3) Top-down and bottom-up modulation can modulate the crossmodal attention shift.(4) In top-down modulation, our brain can identify the modality attention shift instruction very rapidly. The neural activity of crossmodal attention shift induced by auditory cue is different from visual cue.