Data from: Rapid recalibration of speech perception after experiencing the McGurk illusion

The human brain can quickly adapt to changes in the environment. One example is phonetic recalibration: A speech sound is interpreted differently depending on the visual speech and this interpretation persists in the absence of visual information. Here, we examined the mechanisms of phonetic recalibration. Participants categorized the auditory syllables /aba/ and /ada/, which were sometimes preceded by so-called McGurk stimuli (in which an /aba/ sound, due to visual /aga/ input, is often perceived as ‘ada’). We found that only one trial of exposure to the McGurk illusion was sufficient to induce a recalibration effect, i.e. an auditory /aba/ stimulus was subsequently more often perceived as ‘ada’. Furthermore, phonetic recalibration took place only when auditory and visual inputs were integrated to ‘ada’ (McGurk illusion). Moreover, this recalibration depended on the sensory similarity between the preceding and current auditory stimulus. Finally, signal detection theoretical analysis showed that McGurk induced phonetic recalibration resulted in both a criterion shift towards /ada/ and a reduced sensitivity to distinguish between /aba/ and /ada/ sounds. The current study shows that phonetic recalibration is dependent on the perceptual integration of audiovisual information and leads to a perceptual shift in phoneme categorization.人类大脑能够快速适应环境变化，其典型示例为语音重校准（phonetic recalibration）：当结合视觉言语信息时，同一语音会被赋予不同的语义解读，且该解读效应会在无视觉信息的情况下依然持续存在。本研究旨在探究语音重校准的潜在机制。实验中，受试者需对听觉音节/aba/与/ada/进行分类判断，部分试次前会呈现麦格克刺激（McGurk stimulus）——即听觉呈现/aba/、视觉呈现/aga/时，个体通常会感知为“ada”的刺激范式。研究结果显示，仅需单次暴露于麦格克错觉（McGurk illusion），即可引发语音重校准效应：即后续呈现的听觉/aba/刺激会被更多地感知为“ada”。此外，语音重校准仅发生在视听输入整合后被感知为“ada”的场景（即麦格克错觉场景）中。进一步而言，该重校准效应依赖于前置刺激与当前听觉刺激之间的感官相似性。最后，信号检测论（signal detection theory）分析结果表明，麦格克错觉诱导的语音重校准，同时引发了向/ada/分类的判断标准偏移，以及对/aba/与/ada/的辨别敏感性降低。本研究证实，语音重校准依赖于视听信息的知觉整合，并会引发音素分类的知觉偏移。