Over the last decade, research on event-related potential has consistently demonstrated that the reading of visual Chinese disyllabic words involves a centro-parietal N200 component linked to orthographical processing. It is uncertain, though, if this component is present for the identification of single characters. This investigation examined whether Chinese one-character words activate the centro-parietal N200 similarly to two-character words to test whether this component only reflexs the relative position information of two-character words. If the answer is negative, it indicates that the N200 primarily encodes orthographic information, such as the spatial positional relationship between characters. If the answer is positive, it suggests that the N200 at least partially reflects the processing of character level orthographic information.
With three experiments, the present paper explored the brain ERP response induced by one-character Chinese words. In Experiment 1, the ERP potentials induced by one-character and two-character Chinese words were compared under separate or mixed presentation conditions with a semantic judgement task, in which participants had to judge whether or not the presented stimulus was the name of an animal or a plant. In Experiment 2, a lexical decision task, in which participants had to judge whether the presented character was real or pseudo, was employed to determine if N200 is enhanced at the repetitive presentation condition for one-character Chinese words. Non-word character was also manipulated to further explore the nature of N200 effect in Experiment 3.
Results showed that Chinese one-character words also elicited a clear N200 ERP component just like two-character words. Moreover, the N200 enhancement effect in the repetition priming condition was also found, and effect for real words was significantly greater than that for pseudo- and non-word. This revealed that around 200 milliseconds after the presentation of a one-character Chinese word, N200 can already distinguish whether a specific positional relationship of radicals has a pre-exiting representation in the brain, i.e., whether it is a real character. This means that real words have already been differentiated from pseudo-word and non-word at this stage.
These findings suggest that the centro-parietal N200 component reflects the process of integrating visual features into single characters, acting as a neural marker for the orthographic processing of Chinese one-character words. This indicates that the N200 plays a crucial role in identifying and distinguishing between real-, pseudo- and non-word, providing insight into how the brain integrates visual information during early stages of reading. Furthermore, this discovery offers a new perspective for understanding the temporal dynamics for Chinese word recognition and the underlying cognitive mechanisms for written language processing.
