Centro-parietal N200: An event-related potential component specific to Chinese visual word recognition

Almost all written languages currently used in the world are alphabetic or phonologically-based scripts (e.g., English) whose word recognition involves discrimination of one-dimensional linear combinations of several dozens of letters or phonological units, except written Chinese whose vocabulary consists of a large number of block characters, the analysis of which relies on the extraction of 2-dimensional form information at multiple levels including radical, character, and multiple-character word. Whether the dramatic contrast between the 2 types of orthography leads to distinctive mental processes is a fundamental question in psycholinguistic research unanswered in the past three decades. Using event-related potentials and visual lexical decision tasks, we asked native Chinese speakers to discriminate between real Chinese words and pseudo- or non-words and observed a widespread negative deflection with centro-parietal focus elicited 200 ms post-stimulus onset. This N200 response showed a clear and large amplitude enhancement upon word repetition and seems to be specific to Chinese as no similar effects had been reported in word recognition studies involving alphabetic scripts under similar experimental conditions. Further evidence showed that this N200 could not be attributed to non-linguistic sensori-perceptual processes, nor phonological or semantic processes, but likely reflects very early identification of the orthography of individual words involving extensive and higher-level visual analysis. Recently the first author proposed a meaning-spelling theory of written Chinese vocabulary proposing that the Chinese and alphabetic scripts are the only 2 possible logical types of mature human writing systems, and that the former is more thoroughly a visual language compared with the latter and thus shall emphasize more of visual processing. Reinforcing each other, the meaning-spelling theory and the discovery of the centro-parietal N200 reveal the uniqueness of Chinese both theoretically and empirically, and provide strong arguments for the intrinsic distinction between written Chinese and alphabetic scripts.