DataSheet2_Prosodic Differences in Human- and Alexa-Directed Speech, but Similar Local Intelligibility Adjustments.CSV

The current study tests whether individuals (n = 53) produce distinct speech adaptations during pre-scripted spoken interactions with a voice-AI assistant (Amazon’s Alexa) relative to those with a human interlocutor. Interactions crossed intelligibility pressures (staged word misrecognitions) and emotionality (hyper-expressive interjections) as conversation-internal factors that might influence participants’ intelligibility adjustments in Alexa- and human-directed speech (DS). Overall, we find speech style differences: Alexa-DS has a decreased speech rate, higher mean f0, and greater f0 variation than human-DS. In speech produced toward both interlocutors, adjustments in response to misrecognition were similar: participants produced more distinct vowel backing (enhancing the contrast between the target word and misrecognition) in target words and louder, slower, higher mean f0, and higher f0 variation at the sentence-level. No differences were observed in human- and Alexa-DS following displays of emotional expressiveness by the interlocutors. Expressiveness, furthermore, did not mediate intelligibility adjustments in response to a misrecognition. Taken together, these findings support proposals that speakers presume voice-AI has a “communicative barrier” (relative to human interlocutors), but that speakers adapt to conversational-internal factors of intelligibility similarly in human- and Alexa-DS. This work contributes to our understanding of human-computer interaction, as well as theories of speech style adaptation.

本研究旨在检验53名被试在与语音AI助手（voice-AI assistant，亚马逊（Amazon）旗下Alexa）开展预编排口语互动时，其言语适应行为是否区别于与人类对话者互动时的表现。本研究通过交互设计操纵了可懂度压力（即预设的单词识别错误情境）与情绪性表现（即过度情绪化的感叹语）这两类会话内部变量，考察二者对被试在艾拉（Alexa）指向言语与人类指向言语（directed speech, DS）中可懂度调整行为的影响。总体而言，本研究发现两类指向言语存在显著的言语风格差异：相较于人类指向言语，艾拉指向言语的语速更慢、平均基频（mean f0）更高，且基频（f0）波动幅度更大。在针对两类对话者的言语产出中，被试针对单词识别错误所做出的调整行为较为相似：目标词中元音后移（vowel backing）现象更为显著（以增强目标词与误识别词之间的辨识度差异），且句子层面的言语响度更高、语速更慢、平均基频更高，基频波动幅度更大。当对话者展现出情绪化表达后，人类指向言语与艾拉指向言语之间未出现显著差异。此外，情绪化表达并未在单词识别错误引发的可懂度调整中起到中介调节作用。综合来看，本研究结果支持如下假说：讲话者会认为语音AI助手相较于人类对话者存在“沟通障碍”，但在人类指向言语与艾拉指向言语中，讲话者针对可懂度相关会话内部因素所做出的适应行为并无二致。本研究不仅深化了我们对人机交互的认知，同时也为言语风格适应相关理论提供了实证支撑。