Department of Language Science, University of California Irvine, USA.
Department of Linguistics, University of Chicago, USA.
Cognition. 2023 Apr;233:105359. doi: 10.1016/j.cognition.2022.105359. Epub 2022 Dec 20.
Much inquiry in psycholinguistics has focused on evidence from the N400 and P600 components of the event-related potential (ERP) signal-and a central theoretical challenge in this area is accounting for the so-called "semantic P600", which involves unexpected patterns in these components relative to traditional theories of the underlying mechanisms. In this paper we present a computational model of the language processing mechanisms underlying these ERP components, which builds on existing psycholinguistic theories in positing a heuristic interpretation stage of processing, but which deviates from existing theories in formulating this heuristic interpretation process as probabilistic selection via a noisy channel model, and in quantifying and accounting for fine-grained variation in statistical and representational properties of individual stimuli. Our model successfully simulates N400 and P600 patterns from eight psycholinguistic experiments, reflecting the full range of N400-only, P600-only, and biphasic N400-P600 effects, and its behaviors shed light on a number of key patterns that have presented challenges for existing theories. The model's success indicates that a strong account for the processing mechanisms underlying these effects is one in which language comprehension involves a probabilistic heuristic interpretation stage resembling a noisy channel process, feeding into subsequent processes that assess target word fit and reconcile between heuristic and literal interpretations. The model's success also indicates that these mechanisms are critically sensitive to statistical variation in individual stimuli, and that modeling the effects of this variation is essential to account for the full range of observed effects in language processing.
心理语言学中的大量研究都集中在事件相关电位 (ERP) 信号的 N400 和 P600 成分上的证据上——该领域的一个核心理论挑战是解释所谓的“语义 P600”，这涉及到这些成分相对于潜在机制的传统理论的意外模式。在本文中，我们提出了一个语言处理机制的计算模型，该模型基于现有的心理语言学理论，假设处理的启发式解释阶段，但与现有理论不同的是，它将启发式解释过程表述为通过噪声信道模型进行概率选择，以及量化和解释单个刺激的统计和表示性质的细微变化。我们的模型成功地模拟了来自八个心理语言学实验的 N400 和 P600 模式，反映了 N400 仅、P600 仅和双相 N400-P600 效应的全部范围，其行为揭示了许多对现有理论提出挑战的关键模式。该模型的成功表明，对这些效应背后的处理机制的强有力解释是一种语言理解涉及类似于噪声信道过程的概率启发式解释阶段的解释，该阶段为评估目标词拟合度和启发式与字面解释之间的一致性的后续过程提供信息。该模型的成功还表明，这些机制对个体刺激的统计变化非常敏感，并且对这种变化的建模对于解释语言处理中观察到的全部效应至关重要。
