Mismatch negativity (MMN) as an index of asymmetric processing of consonant duration in fake Mandarin geminates

Unlike languages where consonant duration is used contrastively to distinguish word meanings, long consonants in Mandarin Chinese only occur across morpheme boundaries as a result of concatenation and are referred to as fake geminates. To investigate whether Mandarin speakers employ duration contrast to differentiate fake Mandarin geminates and corresponding singletons as well as the underlying pattern of the processing, two auditory oddball tasks were carried out to measure the component of MMN, an index of the automatic detection of deviant stimulus. Mandarin pseudoword pairs which differ only in the duration of the medial consonant ([an1 an1] similar to [an1 nan1] vs. [an2 an2] similar to [an2 nan2]) were used as stimuli. An asymmetric pattern of brain activation was observed where the singleton deviant in the context of geminate words elicited higher MMNs than in the reversed condition. These findings are in line with earlier research suggesting that the singleton is unspecified for a moraic representation, while the geminate is specified. Mandarin speakers can employ duration contrast to distinguish fake geminates and corresponding singletons; furthermore, the processing of fake concatenated geminates in contrast to singletons is similar to that of real geminates and corresponding singletons.