Abstract: Two experiments were conducted in this study, the main purpose was to examinethe inhibitory mechanism of high-skilled and low-skilled comprehenders in processing Chinese two-clause sentences. Twenty-four participants were selected from first-year students in Beijing Science and Technology University for each experiment. They were screened based on the scores on the Multi-Media Language Comprehension Test (MMLCT), with half of them in each group of high-skilled and low-skilled Chinese comprehenders respectively. The experimental paradigm combined self-paced Moving Window procedure and selective recognition task. In each trial, the subjects were instructed to view a target sentence presented word by word in light yellow against black computer screen in a self-paced Moving Window procedure. Three double-character word or non-word distractors, displayed in light blue, were externally inserted in the fixed places of each sentence. The subjects were required to focus on processing target sentences and at the same time to ignore or inhibit the inserted distractors. Each sentence was followed by a probe in white color, to which the subjects should respond by pressing the corresponding keys to indicate whether the probe is one component word in the target sentence. The inhibitory mechanism was examined at two different levels in the meaningfulness continuum in the two experiments respectively. The first experiment examined the inhibitory efficiency to distractors at the lower level of meaningfulness. The distractors were manipulated in two levels, meaningful words and meaningless non-words, so as to examine the effect of the meaningfulness of distractors on inhibitory mechanism. In the second experiment, the effect of topic relatedness of distractors to target sentences on the inhibitory mechanism was concerned. Topic related and unrelated meaningful words were used as the distractors. This was at a higher level of meaningfulness continuum. Thus, higher distractibility was evinced the second than in the first experiment. The results showed: Inhibitory mechanism in self-paced sentence processing was affected by the meaningfulness and topic relatedness of distractors. The more meaningful and topic-related the distractors were, the more difficult they were inhibited. The difference in inhibitory efficiency between high-skilled and low-skilled comprehenders manifested only in the higher distractibility condition of the second experiment. Low-skilled comprehenders had a less-efficient inhibitory mechanism. It could be concluded that at Chinese sentence processing level, the inhibitory mechanism to external distracting information was related to the distractors' meaningfulness and readers' comprehension skills, as well as the distractibility of distractors in some interdependent and interactive ways.

Key words: inhibitory mechanism, self-paced, sentence processing, distractors, language comprehension skill