CAJ | 학술논문

采用知觉干扰效应的经典实验范式，首次利用ERP技术探究知觉干扰效应的内部机制。结果发现，递进条件和标准条件均诱发了P2，P3，N400和晚期正成分LPC。在P2，P3和LPC成分上，标准条件的波幅均显著大于递进条件；在N400成分上，递进条件比标准条件波幅更负，潜伏期更长。此外，对递进条件下靶字各模糊水平（Level 1-Level5）的ERPs进行比较分析表明，N400成分的波幅在各模糊水平间的差异均不显著。基本支持失匹配理论及词汇自动加工理论。
채용지각간우효응적경전실험범식，수차이용ERP기술탐구지각간우효응적내부궤제。결과발현，체진조건화표준조건균유발료P2，P3，N400화만기정성분LPC。재P2，P3화LPC성분상，표준조건적파폭균현저대우체진조건；재N400성분상，체진조건비표준조건파폭경부，잠복기경장。차외，대체진조건하파자각모호수평（Level 1-Level5）적ERPs진행비교분석표명，N400성분적파폭재각모호수평간적차이균불현저。기본지지실필배이론급사회자동가공이론。
The perceptual interference effect is the finding that prior exposures to a more degraded stimulus compromise the identification of a less degraded version of the stimulus later. Up to now, there are two influential theories which explain this effect： competition explanations （Bruner ＆ Potter, 1964; Luo ＆ Snodgrass, 1994） and mismatch explanations （Wang ＆ Reinitz, 2001 ）. Notably, previous studies on perceptual interference almost all focused on the behavioral experiments. However, no study exploring the internal mechanism of this effect on the neurophysiological level has been showed yet. So the aim of this study is to investigate the neurophysiologieal substrate of the perceptual interference effect and to further explore the underlying mechanism of this effect. In additon, in the field of N400 studies, the debate between the prelexical account and the postlexieal account has been very intense. Is the perceptual interference effect related to the N400？ The study of this question may be another way to resolve the debate. According to the perceptual interference effect theory, because the hypotheses compete with each other or the mismatch yields inhibition, we predict that the incremental condition will produce a more negative ERP deflection than the standard condition, and this negativity is likely to be N400. If so, this study will support the N400 lexical process theory. 270 Chinese characters were selected as the experiment materials （ 180 target items and 90 probe items）. Each stimulus was drawn in white color in the center of a 60 x 60 pixel black square window, in the font of Song/Kai Ti 119 in a Flash MX 2004 environment, and then saved as a smoothed BMP image. For targets, each image was then fragmented at blurredness from Level 1 to Level 5 with a fragmentation procedure of Luo and Snodgrass （1994）. In each trial, the participants were first presented with a fixation mark for 300 - 500 ms immediately followed by the target characters. The fragmented stimulus of each character was either gradually completed by adding more pixels to each presentation from the blurredness Level 1 until Level 5 was reached without a blank screen （the incremental condition）, or presented directly at blurredness Level 5 （the standard condintion）. The duration of eaeh fragmented stimulus was 1000 ms, and then a question mark （＂？＂） was presented for a 500 ms sandwiched between two 250 ms black blanks, which was displayed to cue the participants to respond to the subsequent probe character. A black blank was inserted at the end of each trial for 2000 ms. The participants were told to judge as quickly and accurately as possible whether the probe character was identical to the fragmented stimulus presented. The participants were requested to press key ＂ 1 ＂ when the probe matched the fragmented stimulus in identity, or press key ＂ 2 ＂ otherwise. The averaged epoch for ERP was 1200 ms including 1000 ms poststimulus and 200 ms prestimulus. The prominent P2, P3, N400 and LPC were elicited under the experimental conditions. The amplitudes of P2, P3 and LPC were significantly larger in the standard condition than in the incremental condition. The incremental condition elicited a more negative ERP deflection than did the standard condition in the 350 -500 ms （N400） time window around the midline centroparietal recording sites. In addition, we found no significant differences in the 350 ~ 500 ms （N400） time window among the consecutive blurredness Levels during the incremental condition. The results indicate that perceptual interference occurs at the early stages of the incremental condition and it yields an enduring inhibition, during which the inhibition does not seem to change in magnitude. Therefore, the present results are consistent with the mismatch explanation. In addition, the study results are also consistent with the view that the N400 is sensitive to a lexical process.