N400 and P600 event-related potential (ERP) components have long been the object of study in psycholinguistics. Traditional accounts have associated N400 effects with semantic violations, and P600 effects with syntactic violations. However, this picture is complicated by P600 effects—without N400 effects—in response to animacy and thematic- role violations, as well as biphasic N400/P600 effects for conventional semantic violations . Building on explanations involving interplay of plausibility-driven and syntax-driven interpretations, we present a computational model that accounts for these complicating observations via a noisy channel modeling framework. Our model assumes early- stage sentence interpretations determined by noisy channel computation (influenced by plausibility), with these early interpretations driving the N400 amplitude. The P600 amplitude reflects reconciliation of the early interpretation with the true (syntax-driven) interpretation, and is modulated by the extent to which early interpretations deviate from the true input. Running this model on original experimental stimuli, we successfully simulate N400 and P600 effects from seven studies in this literature.
Recommended citation: Li, J. & Ettinger, A. (2021). "A noisy channel model of N400 and P600 effect in sentence processing." Short talk presented at 34th Annual CUNY Conference on Human Sentence Processing.