内源性空间线索有效性对视听觉整合的影响

采用内源性线索-靶子范式, 操纵线索类型(有效线索、无效线索)和靶刺激通道类型(视觉刺激、听觉刺激、视听觉刺激)两个自变量, 通过两个实验, 分别设置50%和80%两种内源性空间线索有效性来考察不同空间线索有效性条件下内源性空间注意对视听觉整合的影响。结果发现, 当线索有效性为50%时(实验1), 有效线索位置和无效线索位置的视听觉整合效应没有显著差异; 当线索有效性为80%时(实验2), 有效线索位置的视听觉整合效应显著大于无效线索位置的视听觉整合效应。结果表明, 线索有效性不同时, 内源性空间注意对视听觉整合产生了不同的影响, 高线索有效性条件下内源性空间注意能够促进视听觉整合效应。

The influence of endogenous spatial cue validity on audiovisual integration

Previous studies usually used the instruction to control the attention of the participants to different spatial locations to investigate the influence of endogenous spatial attention on the audiovisual integration, which found that endogenous spatial attention enhanced audiovisual integration. However, in reality, it is difficult to assign attention in an all-or-none manner. In present study, we used endogenous spatial cue-target paradigm to investigate the effect of endogenous spatial cue validity on audiovisual integration.The current study was a 2 (cue validities: valid, invalid) × 3 (target modalities: visual, auditory, audiovisual) factorial design. A total of 62 undergraduate students were recruited as paid volunteers. Experiment 1 recruited 35 participants (5 males; age range: 18~26 years; mean age: 21.26 ± 1.77 years). Experiment 2 recruited 27 participants (6 males; age range: 19~25 years; mean age: 22.19 ± 1.75 years). The visual (V) target was a white pentagonal asterisk block (2°×2°). The auditory (A) target was a 1600 Hz sinusoidal tone presented by speakers. The audiovisual (AV) target was composed by the simultaneous presentation of both the visual and the auditory stimuli. At the beginning of each trial, the fixation stimulus was presented for 600~800 ms in the center of the monitor. Following the fixation stimulus, the cue was presented for 200 ms, which could predict (50% or 80%) the location of the target. Before the target that appeared for 100 ms, the inter stimulus interval (ISI) lasted for 700 ms. The target (A, V, or AV) randomly appeared for 100 ms in the left or right locations. At last, the fixation stimuli appeared for 600 ms to wait for the correspondence responses to targets. During the experiment, the participants were asked to locate targets by pressing buttons (F/J) as quickly and accurately as possible. The results showed that the responses to AV targets were faster than V or A targets, indicating the appearance of the bimodal advancement effect in both experiments. Each target modality showed significant cueing effect. And the cueing effect in experiment 2 was significantly larger than the cueing effect in experiment 1. In addition, in experiment 1, relative multisensory response enhancement (rMRE), race model (probability difference) showed no significant difference at valid compared to invalid locations. However, in experiment 2, rMRE and race model (probability difference) increased at valid compared to invalid locations. The results suggested that endogenous spatial attention enhanced audiovisual integration in high spatial validity condition. In summary, Endogenous spatial attention had different effects on the audiovisual integration under different spatial cue validity. High spatial cue validity enhanced audiovisual integration. The current study provides direct behavioral evidence for endogenous spatial attention to enhance audiovisual integration.