ERP Signatures of Prediction Error in the Comprehension of Ambiguous Plural Pronouns in German

The referent of a plural pronoun can be ambiguous, posing comprehension challenges. Behavioural studies show an ambiguity advantage, with reduced processing cost for an ambiguous pronoun. This raises the question: “How does ERP evidence for ambiguous plural pronouns align with psycholinguistic research suggesting that incremental interpretation may involve shallow processing?” We present results from an EEG/ERP experiment in German examining plural pronoun contexts (e.g., Sie/they) with antecedents in set-subset relations (e.g., artists ⊃ sculptors) or disjointed (e.g., journalists ⊆ artists), and verbs are ambiguous (e.g., browsed) or unambiguous (e.g., carved). No ERP effects were observed in pronoun or ambiguous predicate cases, suggesting good-enough representations. The set-subset unambiguous context showed an N400 relative to the non-subset case, indicating costs when an ambiguous interpretation is not possible (prediction error). This negativity was positively correlated with surprisal estimates from a Generative Pre-trained Transformer, supporting a shallow processing strategy under less predictive input contexts.