ERP Effects Of Twirled Chinese Characters And Semantic Priming In High And Low Frequency Word Recognition

The mental representation and processing of Chinese words are important topics in cognitive psychology. The definition of character plays an important role in reading. Twirled Chinese Characters resulted in reading difficulties. Some reports proposed hypothesis that space transparency of Chinese character account for the influences of various Chinese characters forms on visual perception of Chinese characters. Space transparency was stroke distance in horizontal and vertical dimensions. This study was designed to investigate whether or not space transparency played a leading role, and prvoe the integrity of space transparency of Chinese character. In the other side, we thought that it was necessary for us to apply a new method beside RT and ACC.Kutas and Hillyard (1980) reported a negative deflection peaking at about 400ms after the target onset when a semantically inappropriate word appeared unexpectedly at the end of a sentence. The amplitude difference between related and unrelated targets was the N400 priming effect.In the past three decades, a significant number of studies have exposed mechanisms underlying N400 priming effect. This N400 priming effect was interpreted in terms of word level automatic process and postlexical mechanisms that was conscious and attentional. From those results, we could inference that N400 reflects both automatic and postlexical process. There was defect of both theories. This study advanced a new theory that N400 was related to a lexical verification explanation constructed on the base of the verification model provided by Becker and Killion, but they are not expected from the post-lexical processing theories.Using ERP technique and priming paradigm, the present study adopted a delayed character-matching task to investigate character-twirling effects in Chinese characters of high and low frequency, and their interactions with semantic priming.In experiment 1, we used high frequency Chinese characters. Three characters were presented in succession in each trial of the character-matching task, representing prime, target and probe stimulus respectively. The primes were intact characters, while both the targets and probes were twirled ones. Two variables, priming and twirling, were manipulated with a 2×2 factorial within-subjects design in the experiment, and ended up with 4 treatment conditions, which were primed twirled, primed intact, unprimed twirled, and unprimed intact conditions. The subjects were asked to press a key on keyboard if the target and the probe, which followed the target, were a same character in identity, and press another one if not. Sixteen native Chinese undergraduates or graduates participated in the experiment during which they were instructed to make a yes/no distinction in the task. The data showed twirled targets were even elicited more negative N170 than were the intact. Moreover, related to primes had elicited smaller N400 compared with unrelated targets. We analysed the notion that N170 reflectded a perceptual analysis of visual character configuration. It also proved space transparency was incorporated.Experiment 2, same as experiment, was manipulated with a 2×2 factorial within-subjects design. Experiment Materials were changed to Chinese characters of low frequency. Three-way repeated-measures ANOVAs with factors of Twirling (twirled, intact), priming (primed, unprimed), and Electrode Site revealed significant main effects of twirling at the 150-300ms interval. The peaks of N170 elicited by the twirled targets were more negative compared with the intact targets. These findings support the notion that N170 reflects a perceptual analysis of visual character configuration. At the 300-500ms interval, similar ANOVAs but conducted on mean amplitude revealed significant main effects of both semantic priming and twirling, and revealed no significant interactions. The amplitude of N400 elicited by target characters was significantly larger in unprimed conditions than in primed trials. More importantly, the amplitude of N400 was significantly larger in twirled than in intact conditions.This study supported the notion that N170 reflectded a perceptual analysis of visual character configuration. It also proved space transparency was incorporated. N400 was related to a lexical verification explanation constructed on the base of the verification model provided by Becker and Killion, but they are not expected from the post-lexical processing theories.