Vatakis Argiro, Spence Charles
Department of Experimental Psychology, University of Oxford, Oxford, England.
Percept Psychophys. 2007 Jul;69(5):744-56. doi: 10.3758/bf03193776.
We investigated whether the "unity assumption," according to which an observer assumes that two different sensory signals refer to the same underlying multisensory event, influences the multisensory integration of audiovisual speech stimuli. Syllables (Experiments 1, 3, and 4) or words (Experiment 2) were presented to participants at a range of different stimulus onset asynchronies using the method of constant stimuli. Participants made unspeeded temporal order judgments regarding which stream (either auditory or visual) had been presented first. The auditory and visual speech stimuli in Experiments 1-3 were either gender matched (i.e., a female face presented together with a female voice) or else gender mismatched (i.e., a female face presented together with a male voice). In Experiment 4, different utterances from the same female speaker were used to generate the matched and mismatched speech video clips. Measuring in terms of the just noticeable difference the participants in all four experiments found it easier to judge which sensory modality had been presented first when evaluating mismatched stimuli than when evaluating the matched-speech stimuli. These results therefore provide the first empirical support for the "unity assumption" in the domain of the multisensory temporal integration of audiovisual speech stimuli.
我们研究了“统一性假设”是否会影响视听言语刺激的多感官整合。根据这一假设，观察者认为两种不同的感官信号指的是同一个潜在的多感官事件。我们采用恒定刺激法，以一系列不同的刺激起始异步向参与者呈现音节（实验1、3和4）或单词（实验2）。参与者对先呈现的是哪个流（听觉或视觉）进行无速度限制的时间顺序判断。实验1 - 3中的听觉和视觉言语刺激要么是性别匹配的（即女性面孔与女性声音一起呈现），要么是性别不匹配的（即女性面孔与男性声音一起呈现）。在实验4中，使用同一位女性说话者的不同话语来生成匹配和不匹配的语音视频片段。从恰可察觉差异的角度衡量，所有四个实验的参与者都发现，在评估不匹配刺激时比评估匹配语音刺激时更容易判断先呈现的是哪种感官模态。因此，这些结果为视听言语刺激的多感官时间整合领域中的“统一性假设”提供了首个实证支持。
