主題：The Role of Orthographic Neighborhood Effects in Chinese Word Recognition: Integrating Cognitive Theories with Neuroimaging（漢語中的家族效應在詞彙加工歷程中所扮演的角色——結合認知模型與大腦神經影像）
The orthographic neighborhood effects have been widely investigated in research on word recognition in alphabetic systems. Two issues have been discussed in regard to neighborhood, one of which concerns neighborhood size (NS), and the other neighborhood frequency (NF). However, only very few studies have conducted the exploration of neighborhood effects in Chinese. Therefore, the present study further investigated the possible role of neighborhood effects in Chinese two-character word recognition.
We manipulated the word frequency and the NS simultaneously in Study I, with the leading character frequency controlled, to explore their influences on word lexical decision and naming. The results showed a robust effect that words with a larger NS produced shorter reaction time than those with a smaller NS, irrespective of the word frequency and the tasks. This facilitative effect may occur due to a semantic network formed by neighbor words, resulting in the semantic activation to accelerate the word recognition.
Additionally, different from alphabetic systems, NF in Chinese is usually confounded by component character frequency and NS. In Study II, three experiments were designed to explore the role of NF effect in Chinese and the stimuli were all two-character words. This effect was evaluated on targets with- and without- higher frequency neighbors with NS matched. Among the experiments, the patterns of the leading character frequency effect and word frequency effect in the naming and lexical decision tasks were compared. The results implied an inhibitory NF effect in Chinese word recognition.
Importantly, integrating these results of Study I and II, a possible cognitive mechanism of orthographic neighborhood effects was proposed in this thesis. Moreover, the comparison of the effect sizes of word frequency between the two different types of task showed that lexical decision responses demonstrated a larger word frequency effect, indicating that the sub-word processing was involved in the multi-character word recognition.
Study III is the first to demonstrate that negative NS effects (i.e., stronger activation for small NS condition than for large NS condition) in Chinese word recognition produce greater activations in the left ventral inferior frontal gyrus, right inferior frontal gyrus, left inferior parietal lobule and left fusiform gyrus. Moreover, the findings of Study III fully support the semantic activation model presented in Study I by indicating that NS effects indeed involve semantic processing in Chinese word recognition and therefore provide strong evidence from neuroimaging.