N400 repetition effect in unidentifiable Chinese characters: evidence for automatic process.

A new matter of debate is whether N400 is exclusively sensitive to automatic or postlexical processes. Recent studies showing N400 modulation by masked primes support an automatic process account. However, these studies cannot directly prove an automatic process. Event-related brain potentials to blurred targets were recorded to substantiate N400 repetition (priming) effects as an index of pure automatic process during a matching task with Chinese characters. Highly blurred target characters, which were unidentifiable, as well as identifiable target characters were shown to elicit greater N400 when repeated, with N400 peak latency being longer for slightly blurred targets than for highly blurred targets. These results provide evidence that N400 is modulated directly by automatic processes rather than by postlexical processes.