Electrophysiological evidence for incremental lexical-semantic integration in auditory compound comprehension

The present study investigated the time-course of semantic integration in auditory compound word processing. Compounding is a productive mechanism of word formation that is used frequently in many languages. Specifically, we examined whether semantic integration is incremental or is delayed until the head, the last constituent in German, is available. Stimuli were compounds consisting of three nouns, and the semantic plausibility of the second and the third constituent was manipulated independently (high vs. low). Participants' task was to listen to the compounds and evaluate them semantically. Event-related brain potentials in response to the head constituents showed an increased N400 for less plausible head constituents, reflecting the lexical-semantic integration of all three compound constituents. In response to the second (less plausible) constituents, an increased N400 with a central-left scalp distribution was observed followed by a parietal positivity. The occurrence of this N400 effect during the presentation of the second constituents suggests that the initial two non-head constituents are immediately integrated. The subsequent positivity might be an instance of a P600 and is suggested to reflect the structural change of the initially constructed compound structure. The results suggest that lexical-semantic integration of compound constituents is an incremental process and, thus, challenge a recent proposal on the time-course of semantic processing in auditory compound comprehension.