本論文進行兩個眼動實驗，探討語境及多義特性在一詞多義處理歷程中扮演的角色。Frazier與Rayner(1990)認為一詞多義由於詞義間有重疊的語義屬性(sense overlap)，因此處理詞義之初，會先以部分語義(partial specification)來理解，不需立即進行完整詞義的解讀，支持部分語義解讀假設(Immediate Partial Interpretation Hypothesis)。在Frisson 與Pickering(2001)所提出詞義未定模型(Underspecification Model)中，進一步說明語境在一詞多義中扮演的角色，認為一詞多義的語義提取會先以未定意義(underspecified meaning)解釋，在語義提取完畢後，語境才會介入詞義的選擇。本論文操弄語境導引和詞義重疊性，來探討一詞多義的詞義提取與選擇歷程。實驗一操弄句子中目標詞的語境預測力(可預測語境vs.不可預測語境)與詞義數量(單詞義vs.多詞義)，記錄並分析目標詞與目標詞後區域的凝視時間。結果顯示：目標詞上的凝視時間多詞義顯著短於單詞義，支持部分語義解讀假設。然而，實驗一在目標詞後區域並未看到多詞義因延遲語義解讀(delayed semantic commitments)而造成抑制或競爭效果。實驗二就此現象與「一詞多義本身的詞義重疊程度」與「語境對一詞多義有無發生語義解讀的必要性」進行進一步探討。實驗二(同實驗一)操弄目標詞的語境預測力，與詞義的重疊程度(單義詞vs.中度詞義重疊vs.高度詞義重疊)，並控制語境偏向次要詞義的情形。結果顯示：目標詞上的晚期眼動指標在中度詞義重疊(中vs.單)與高度詞義重疊(高vs.單)皆看到與語境預測力發生交互作用，顯示語境預測力的影響在晚期階段發生；目標詞後區域觀察到中度與高度詞義重疊(中vs.單；高vs.單)皆在不可預測語境下發生詞義抑制效果，符合詞義未定模型預期之延遲語義解讀效果，並在目標詞晚期眼動指標看到中度詞義重疊效果與高度詞義重疊效果(單-中 vs. 單-高)受語境影響有不同的效果，顯示詞義重疊會影響詞義選擇的必要性。總結本論文的結果：首先，一詞多義的語義提取符合部分語義解讀的假設，而語境介入的影響支持詞義未定模型的看法，即語境在語義提取之初並未介入影響，在語義未定的情況下，若語境內容有進行語義解讀之必要時，則會發生延遲語義解讀。其次，詞義的促進效果與一詞多義的詞義數量多寡有關，詞義數量減少時，詞義促進效果也隨之消失。最後，當語境偏向一詞多義的次要詞義時，延遲語義效果才會發生。 / This thesis conducted two eye movement experiments with the aim to investigate the role of context and multi-sense feature in processing polysemy. Frazier and Rayner (1990) suggested that, at the beginning of semantic processing, polysemy is comprehended with partial specification. There is no immediate need to process the complete word sense due to the sense overlap between senses. This viewpoint supports the Immediate Partial Interpretation Hypothesis. In Frisson and Pickering’s (2001) Underspecification Model, further elaboration were made on the role of context in the process of retrieving and selecting one of the word senses of a polysemy. The sense that is first retrieved from a polysemy is considered to be an underspecified meaning. It is after the semantic retrieval is finished that context is involved in selecting a word sense. This thesis manipulated context guidance and sense overlap, to further research on processing polysemy in terms of word sense retrieval and selection. Experiment One manipulated contextual predictability (predictable context vs. unpredictable context) and number of senses (one-sense, monosemy vs. many-sense, polysemy) of the target words in sentences. Fixation times of the target words and post-target areas were recorded and analyzed. Results showed that the fixation times on target words were significantly shorter for polysemy than for monosemy, supporting the Immediate Partial Interpretation Hypothesis. However, in Experiment One, there is no inhibitory or competitive effect on the post-target area, indicating that there is no effect of delayed semantic commitments while comprehending polysemy. In Experiment Two, we further investigated how this phenomenon is connected with the degree of sense overlap and whether context is necessary to activate semantic commitment for polysemy. Contextual predictability of target words and the degree of sense overlap (monosemy vs. moderate-sense-overlap vs. high-sense-overlap) were manipulated, with the former designed as in Experiment One. Specifically, the context was controlled to bias toward the subordinate sense. The results showed that there were interactions of sense overlap degree (both moderate-sense-overlap vs. monosemy and high-sense-overlap vs. monosemy) and contextual predictability on target words for later-stage indices. This suggests that contextual predictability effects at later stages. On the post-target areas, there were inhibitory effects found for moderate-sense-overlap vs. monosemy and for high-sense-overlap when the context is unpredictable. This finding supports the delayed effect of semantic commitments in the Underspecification Model. Moreover, effects of sense overlap (polysemy-moderate vs. polysemy-high) were modulated by contextual predictability on target words for later-stage processing, showing that sense overlap affects the necessity of semantic commitments. In conclusion, the semantic retrieval of polysemy can be best explained by the Immediate Partial Interpretation Hypothesis and the involvement of contextual constraint supports the Underspecification Model. That is, context does not affect the beginning phase of semantic retrieval. Since the senses are underspecified, delayed semantic commitment occurs if it is necessary to make semantic commitment in the context. Furthermore, the facilitation of senses is related to the number of a polysemy’s senses. As number of senses decreases, facilitation of senses wanes and disappears. Finally, delayed semantic commitment occurs only when the context biases towards a subordinate sense of the polysemy.