本研究探討中文讀者對於中文雙字詞的早期語意處理，特別要探討的是中文讀者是否能在凝視一個中文雙字複合詞之前，即可提取該詞的語意資訊。在中文的閱讀研究中曾經發現單字的語意資訊可以在該單字被凝視之前提取，不論是成詞的單字或是多字詞其中的組成單字。也有證據顯示中文雙字詞或雙字複合詞呈現在中央視野時的處理方式是整詞處理。由於事實上就詞長來看，雙字詞的詞類數量為中文詞類的最大宗，也是最常被使用的詞類，因此中文雙字詞語意處理的時間歷程便是本研究的研究目標。 　　實驗一旨在檢視雙字詞的語意資訊是否能和單字一樣，在被凝視之前即被提取。本實驗採用邊界典範（Boundary paradigm, Rayner, 1975），除了目標詞預視（identical preview）之外，本實驗亦包含語意相關預視（semantic-related preview）、語意無關預視（semantic-unrelated preview）及非詞預視（nonword preview）。實驗發現語意相關預視能促進目標詞的處理。然而和預視空間（preview space）及預視時間（preview time）的交互作用則顯示語意預視效益（benefit）在預視空間較大的時候會隨著預視時間拉長而增加，在預視空間較小的時候，則會隨著預視時間漸減。 　　在實驗一中，語意關聯性的高低和該詞合理性（plausibility）的高低是共變的，因此這兩個要素構成一個混淆的因子。語意相關預視和語意無關預視之間的效果有可能來自語意關聯性的差異，或是來自在句中合理性的差異。合理性同時也能解釋在為何在實驗一中，不合理的語意無關預視在目標前詞（pretarget）上造成較短的閱讀時間。為了解決這項混淆的因子，實驗二因此採用對目標詞預視、語意相關預視、及語意無關預視都合理的句子。結果發現，語意預視的主要效果消失。然而交互作用的模式則顯示出，語意預視效益在較長的預視時間、較大的預視空間下仍會存在。但在較小的預視空間下，會隨著較長的預視時間而轉為耗損（cost）。實驗二的結果因此提供證據支持在沒有合理性的交互作用下，中文雙字詞的語意預視效應仍會發生。最後，兩個實驗的差異顯示在中文閱讀中存在合理性的預視效益，此結論和之前中文閱讀的研究結果一致。 / The present study investigates the early semantic processing of Chinese two-character words by Chinese readers. Specifically, whether Chinese readers are able to extract semantic information of an up-coming two-character compound as a whole when the word is yet being fixated. In Chinese, it has been demonstrated that semantic information can be extracted from a single character, whether it is a word or part of a word, before the character is being fixated. There is also evidence for whole word processing of foveally presented two-character compounds/words. Since two-character words actually constitute the majority of word type and are used most frequently in total, the time course of processing the meaning of such combination of characters during reading is then the goal of this study. The first experiment aimed to examine whether semantic information of a two-character word can be extracted before it is fixated, as what have been found for single characters. Boundary paradigm (Rayner, 1975) was used, with identical, semantic-related, and semantic-unrelated words, as well as nonwords as preview. Semantic-related preview did facilitate target word processing. The interaction pattern of the effects with preview space and preview time, however, showed that semantic preview benefit could increase with preview time with small preview space, but decrease with preview time under large preview space. A possible confounding factor in the first experiment was the overlap between semantic relatedness and plausibility. The effect between semantic-related and semantic-unrelated previews could be of semantic or plausibility nature. Plausibility may also explain the shortened fixation duration found in Experiment 1 when implausible semantic-unrelated preview was presented parafoveally. Experiment 2 then solved this confounding by using sentence frames which are plausible for identical, semantic-related, and semantic-unrelated previews. In Experiment 2, main effect of semantic preview benefit disappeared, while the interaction patterns showed that such benefit existed for large preview space with long preview time, but became cost for small preview space with long preview time. The results of Experiment 2 thus provide evidence for semantic preview effect of Chinese two-character words without the interaction with plausibility. Finally, the discrepancies between the two experiments indicate the existence of plausibility preview benefit, which previous studies have suggested to exist in Chinese.

本文透過操弄雙字詞詞首的語意(sense)多寡和左右視野，試圖探討中文雙字詞的語意表徵和左右大腦對於多意詞(polysemy)的處理機制。實驗一顯示的左右腦結果和Pylkkänen等人在2006年的MEG研究相似，也就是左腦的多意詞促進效果，支持多意詞單一表徵的型態；然而，右腦卻呈現多意詞抑制的效果。這樣的現象產生兩者可能解釋：(1) 右腦還是屬於單一語意表徵，但由於右半腦處理語意的特性，導致和左腦得到不同的結果；(2)右腦的結果是來自於右腦屬於語意多重表徵(separate entries)的因素。為了要釐清這些說法，實驗二進一步的改變作業深度，讓受試者做詞類判斷作業，企圖讓受試者進行比較深層的語意處理。實驗二結果顯示，在改變作業深度之後，我們的確得到右腦語意促進效果，所以證明右腦的語意屬於單一表徵，在比較深層作業處理階段，因為左右腦處理語意的特性，使得右腦有機會呈現實驗預期的結果。另外，在動詞、名詞事後分析的結果中，我們也發現動詞、名詞的語意效果在大腦有不同的分布區位。名詞的語意效果分布在大腦中間偏後的位置；動詞則是主要分布在大腦前額一帶 總結以上發現，本研究的發現支持過去學者所提出的多意詞單一表徵的說法；第二、本研究對左右半腦處理語意特性，也符合過去的假設，也就是左腦擅長主要、細微的辨識，右腦則擅長維持次要、普遍語意。第三、本研究額外的發現是，動詞、名詞的語意效果在大腦有不同的分布，意味著不同的詞類在大腦可能有不同的表徵。 / Acknowledgements …………………………………………………………iv Tables…………….……………………………………………………………ix Figures …………………………………………………………………………x Chinese Abstract …………………………………………………………xii English Abstract ………………………………………………………xiii CHAPTER 1. INTRODUCTION ……………………………………………………..……1 1.1 What are senses? Homonymy vs. Polysemy …………………….1 1.2 English words vs. Chinese compounds ………………………….3 1.3 Hemispheric processing of semantic ambiguity ……………4 2. REVIEW OF RELATED PSYCHOLINGUISTIC RESEARCH ………………6 2.1 Neighborhood size effect in English …………………………6 2.2 Neighborhood frequency effect …………………………….……9 2.3 Event-related potentials (ERPs) vs. neighborhood size effect....11 2.3.1 Event-related potentials ………………………………….11 2.3.2 The advantages of electrophysiological techniques …12 2.3.3 Language-related ERP components ……………………….…12 2.3.4 The neighborhood size effect and. ERPs ……………..14 2.4 Neighborhood size effect in Chinese ……………………….16 2.5 Lexical ambiguity in English—homonymy vs. polysemy……… 22 2.5.1 Mixed results of ambiguity effects ………………………23 2.5.2 Polysemy—separate entries or single entry? …………25 2.5.3Some evidence for single entry hypothesis of senses…27 2.6 Lexical ambiguity in Chinese …………………….……………26 2.7 Hemispheric asymmetry in lexicon processing ……………33 3. EXPERIMENT 1 ………………………………………………………………38 3.1 Experiment 1... ..……………………………………….….....39 3.1.1 Participants …………………………………………………………39 3.1.2 Materials ……………………………………………………………39 3.1.3 Procedure ……………………………………………………………40 3.2 EEG recording parameters …………………………………………41 3.3 EEG data analysis procedure …………………………….....42 3.4 Results ……………………………………………………………………43 3.4.1 Behavioral data of sense effect ……………………………43 3.4.2 Behavioral data of lexicality effect ……………………44 3.4.3 Event-related potentials ………………………………….…45 N170 (150- 180 ms) …………………………………………………46 Frontal P200 (220-260 ms) …………………………………….……47 N400 …………………………………………………………………48 3.5 Discussion ……………………………………………………………51 4. EXPERIMENT 2 ……………………………………………………………57 4.1 Experiment 2 …………………………………………………………58 4.1.1 Participants ………………………………………………………58 4.1.2 Materials …………………………………………………………58 4.1.3 Procedure ……………………………………………………………59 4.2 Results …………………………………………………………………60 4.2.1 Behavioral data ……………………………………………………60 4.2.2 ERP data ……………………………………………………………61 N170 (150-180 ms) ………………………………………………....62 Frontal P200 (220-260 ms) …………………………………………63 N400 (350-500 ms) …………………………………………………63 4.3 Discussion …………………………………………………………………….65 Nouns and verbs ………………………………………………………67 4.4 Re-analyses …………………………………………………………69 4.4.1 Behavioral data ……………………………………………………69 4.4.2 ERP data ……………………………………………………………....71 Nouns …………………………………………………………………71 Verbs …………………………………………………………………74 4.5 Discussion 2 ………………………………………………………77 5. GENERAL DISCUSSION AND CONCLUSIONS ………………………81 5.1 Separate entries or single entry? …………………………81 5.2 Hemispheric processing of polysemy in different depth of tasks ………....82 5.3 Nouns and verbs ………………………………………………………84 5.4 Conclusions …………………………………………………………….85 References ……………………………………………….……………………86 Appendixes ………………………………………………………….…….94 / The current study used the manipulation of visual field and the number of senses of the first character in Chinese disyllabic compounds to investigate the representation of senses and the hemispheric processing of semantic polysemy. The ERP results in experiment 1 revealed crossover patterns in the LH and RH, which resembled the MEG data in Pylkkänen et al.’s study (2006). The sense facilitation in the LH was in favor of the assumption of single entry representation for senses. However, the inhibition in the RH yielded two possible interpretations: (1) the nature of hemispheric processing in dealing with semantic ambiguity; (2) the semantic activation from the separate-entry representation for senses. To clarify these possibilities, the depth of the task was changed. Experiment 2 was designed to push subjects to a deeper level of lexical processing through the word class judgment task. The results revealed the sense facilitation effect in the RH and suggested that in a deeper level, the RH had more possibility to observe the sense facilitation due to different efficiency of cerebral hemispheres in dealing with ambiguity. By chance, planned comparisons of the sense effect in different word classes suggested different distributions of the sense effects for nouns and verbs. For nouns, the sense effects were located in central-to-parietal areas while for verbs, the sense effects mainly were from the frontal area. In sum, the current study was in support of the account of single entry representation for senses, which was consistent with previous findings proposed by Beretta et al. (2005), Pylkkänen et al. (2006), and Rodd et al. (2002). Second, the research demonstrated that cerebral hemispheres played a role in semantic activation in a complementary way in which the LH was engaged in fine and focused semantic coding while the RH was more sophisticated in coarse coding and maintaining alternate meanings (e. g. Beeman & Chiarello, 1998; Burgess and Simpson, 1988). When the depth of tasks was changed, the RH advantage for the processing of semantically related senses was observed. Third, different distributions of the sense effects for nouns and verbs implied the distinct representations for different parts of speech in the brain.