The temporal features of self-referential processing evoked by national flag.

The present study explored the neural correlates underlying the psychological processing of self-national flag. Event-related potentials were recorded for national flags while subjects performed a three-stimulus oddball task. The results showed that self-referential stimulus (self-national flag) elicited longer N1 latency and larger N2 amplitude than did non-self-referential stimuli (the familiar and unfamiliar flags). Furthermore, larger P3 amplitudes were showed for self-referential stimulus than for familiar and unfamiliar stimuli. Moreover, in terms of lateralization, the self-referential effect was more obvious on the left region sites. Thus, the present study showed that the self-referential effect not only occurred in late P3 processing stage, but also in early N1 and N2 processing stages, and further demonstrated a left laterality for self-referential processing by using the self-national flag as the self-relevant stimulus.