Perception of lexical neutral tones in mandarin compounds: Electroencephalographic evidence from an oddball paradigm

The present electroencephalographic (EEG) study was designed to investigate the perception of Mandarin neutral tone (T0) by adult Mandarin speakers. For this purpose, we examined the event-related brain potential (ERP) correlates of T0 processing in two-character Mandarin compounds. Eighteen native Mandarin speakers were tested using a modified oddball paradigm. Sixty strong-strong and 60 strong-weak (T0) disyllabic Mandarin compounds were selected from the Contemporary Chinese Dictionary. Participants performed one explicit task of stress discrimination (i.e., deciding whether the fourth word in sequences of 4 spoken words had the same stress pattern as the previous words or a different one) and one implicit task of passive listening. Behaviorally, accuracy showed that Mandarin listeners were able to correctly discriminate T0 from the canonical strong-strong stress pattern in 87.2% of cases. Neurophysiologically, larger N200 and P200 were observed for the infrequent strong-weak stress pattern compared to the canonical strong-strong one. Critically, a N325 was replicated in Mandarin, with a larger N325 for strong-weak than for strong-strong compounds. Consistently with a previous interpretation proposed by Böcker et al. (1999) for Dutch, we argue that the N325 might be a manifestation of the extraction of stress pattern in Mandarin also. Taken together, the present data on T0 perception in Mandarin are discussed in the context of the Prosody-Assisted-Processing (PAP) model (Isel et al., 2003), a cognitive model of spoken compound processing based on stress-timed languages, which postulates an early involvement of prosody in order to guide the morphological analysis at the lexical level.