Distinguishing lexical- versus discourse-level processing using event-related potentials

Two experiments examine the links between neural patterns in EEG (e.g., N400s, P600s) and their corresponding cognitive processes (e.g., lexical access, discourse integration) by varying the lexical and syntactic contexts of co-referential expressions. Experiment 1 examined coreferring expressions when they occurred within the same clause as their antecedents (John/Bill warmly dressed John). Experiment 2 examined between-clause co-referencing with expressions that also varied in lexical frequency (John/Weston went to the store so that John/Weston could buy milk). Evidence of facilitated lexical processing occurred after repeated names, which elicited smaller N400s, as compared with new names. N400s were also attenuated to a greater degree for low-frequency expressions than for high-frequency ones. Repeated names also triggered evidence of postlexical processing, but this emerged as larger P600s for within-clause co-referencing and delayed N400s for between-clause co-referencing. Together, these results suggest that linguistic processes can be distinguished through distinct ERP components or distinct temporal patterns.