The development of mismatch responses to Mandarin lexical tones in early infancy.

This study examined how maturation and the size of deviance affect the development of mismatch responses to Mandarin lexical tones by a multi-deviant oddball paradigm with both large deviant T1/T3 and small deviant T2/T3 pairs in newborns and 6-month-olds. The T1/T3 pair elicited a positive mismatch response (P-MMR) at birth but an adult-like mismatch negativity (MMN) at 6 months of age. For the T2/T3 pair, no significant MMR was seen in newborns, whereas a P-MMR was found when infants are 6 months old. Results suggest that the developmental trajectories of MMRs are dependent on the neural maturation and the discriminability of tonal changes.