Resolving conflicting interpretations: Theta band oscillations and the role of cognitive control.

While processing language, readers and listeners frequently encounter conflicting cues and must select the most plausible interpretation from incompatible alternatives. We tested the hypothesis that cognitive control aids in resolving representational conflicts by biasing processing toward the correct interpretation when multiple analyses of linguistic input are possible. Participants read temporarily ambiguous sentences alongside semantically and syntactically anomalous sentences. Ambiguous sentences, such as "While Anna dressed the baby spit up on the bed," require resolving conflicts between competing interpretations, whereas semantic and syntactic anomalies, though they increase processing demands, do not involve such conflicts. Building on evidence from non-linguistic tasks, we used EEG to assess whether neural oscillations in the theta band (4-8 Hz) serve as a real-time index of cognitive control in resolving conflicting interpretations of linguistic input. Our findings revealed increased theta-band activity over right frontal electrodes during the processing of ambiguous sentences, indicating cognitive control engagement. Additionally, a neural decoding analysis showed that theta-band activity reliably distinguished between correctly and incorrectly understood ambiguous sentences, suggesting that theta activity not only reflects cognitive control engagement but also guides comprehenders toward the correct interpretation. In contrast, ERP analyses showed the expected P600 effects for syntactic anomalies and N400 effects for semantic anomalies, confirming the processing complexity associated with these sentences; however, theta power did not increase for these items. The results support the hypothesis that theta-band oscillations specifically reflect cognitive control processes involved in resolving representational conflicts in language comprehension, helping to prevent interpretation errors and providing insights into the temporal dynamics of cognitive control during sentence processing.