Spoken language is often, if not always, understood in a context formed by the identity of the speaker. For example, we can easily make sense of an utterance such as "I'm going to have a manicure this weekend" or "The first time I got pregnant I had a hard time" when spoken by a woman, but it would be harder to understand when it is spoken by a man. Previous ERP studies have shown mixed results regarding the neurophysiological responses to such speaker-content mismatches, with some reporting an N400 effect and others a P600 effect. In an EEG experiment involving 64 participants, we used social and biological mismatches as test cases to demonstrate how these distinct ERP patterns reflect different aspects of rational inference. We showed that when the mismatch involves social stereotypes (e.g., men getting a manicure), listeners can arrive at a "literal" interpretation by integrating the content with their social knowledge, though this integration requires additional effort due to stereotype violations-resulting in an N400 effect. In contrast, when the mismatch involves biological knowledge (e.g., men getting pregnant), a "literal" interpretation becomes highly implausible or impossible, leading listeners to treat the input as potentially containing errors and engage in correction processes-resulting in a P600 effect. Supporting this rational inference framework, we found that the social N400 effect decreased as a function of the listener's personality trait of openness (as more open-minded individuals maintain more flexible social expectations), while the biological P600 effect remained robust (as biological constraints are recognized regardless of individual personalities). Our findings help to reconcile empirical inconsistencies and reveal how rational inference shapes speaker-contextualized language comprehension.

翻译：口语理解通常（即便不是总是）发生在由说话者身份构成的语境中。例如，当女性说出"我这周末要去美甲"或"我第一次怀孕时很辛苦"时，我们能够轻松理解，但若同样话语由男性说出则较难理解。先前的事件相关电位（ERP）研究对此类说话者-内容失配的神经生理反应显示出不一致的结果：部分研究报道N400效应，另一些则报道P600效应。在一项包含64名参与者的脑电图实验中，我们以社会性和生物性失配作为测试案例，论证了这些不同的ERP模式如何反映理性推理的不同层面。研究表明：当失配涉及社会刻板印象（如男性做美甲）时，听者可通过将话语内容与社会知识整合达成"字面"理解，尽管这种整合因违反刻板印象需要额外认知努力——表现为N400效应；相反，当失配涉及生物学知识（如男性怀孕）时，"字面"理解变得极不可能或完全不可能，促使听者将输入视为可能存在错误并启动修正加工——表现为P600效应。支持这一理性推理框架的是，我们发现社会性N400效应随听者开放性人格特质增强而减弱（因思想开放的个体保持更灵活的社会预期），而生物性P600效应则保持稳定（因生物学约束不受个体人格差异影响）。本研究结果有助于调和实证研究的不一致性，并揭示理性推理如何塑造说话者情境化的语言理解过程。