| 摘要: | 瞳孔大小受交感神經與副交感神經活動平衡的調控，並廣泛使用作為認知歷程的生理指標，且其神經機制涉及藍斑核–正腎上腺素系統。雖然越來越多的研究利用瞳孔大小來探討認知功能，但針對語言處理，尤其是中文閱讀的研究仍極為有限。本論文透過兩項實驗探討瞳孔大小在閱讀中文歷程的角色，重點聚焦於詞頻效應。實驗一中，採用了語義 Go/No-Go 任務，同步記錄瞳孔大小與腦電訊號。操弄變項包含中文雙字詞的詞頻與周邊背景亮度。結果顯示，高頻詞的反應時間顯著快於低頻詞。此外，詞頻同時調節了N400振幅與瞳孔反應：低頻詞誘發較負向的N400振幅與較大瞳孔擴張。然而，在線性混合效應模型顯示，瞳孔擴張與N400振幅在單一試次層級上並無相關。此結果表明，儘管兩者皆對詞頻敏感，但反映的可能是獨立的認知處理歷程。實驗二中，進一步檢驗詞頻與瞳孔大小在中文句子閱讀中的作用。線性混合效應模型分析顯示，詞頻顯著影響閱讀眼動指標。低頻詞誘發較長的首次凝視時間、凝視時間與單次凝視時間。然而，無論是瞳孔絕對大小或瞳孔變化量，皆未與閱讀眼動指標呈現相關。這些結果顯示，在自然句子閱讀中，瞳孔大小可能無法有效反映閱讀中的認知處理歷程。總結而言，本研究發現瞳孔擴張量在中文單字閱讀中反應有別於N400振幅的認知歷程，但在句子閱讀情境中，瞳孔大小的作用不顯著，這可能是因為自然閱讀中的眼跳與字詞辨識歷程複雜的交互影響。未來仍需更多研究進一步探討瞳孔大小在中文閱讀歷程中的影響。;Pupil size is controlled by the balanced activity of the sympathetic and parasympathetic branches of the autonomic nervous system, and is widely used as an index of cognitive processing, arguably mediated by the locus coeruleus–norepinephrine system. While an increasing number of studies have used pupil size to investigate cognitive functions, research focusing on language processing, particularly in reading Chinese, remains extremely limited. This thesis presents two experiments examining the role of pupil size in reading Chinese, in the context of word frequency effects. In Experiment 1, a semantic Go/No-go task was employed, with simultaneous recordings of pupil size and EEG signals. Word frequency (Chinese two-character words) and peripheral background luminance were systematically manipulated. Results showed significantly faster reaction times for high-frequency words compared to low-frequency words. Additionally, word frequency modulated both N400 amplitudes and pupillary responses: lower-frequency words elicited more negative-going N400 amplitudes and larger pupil dilation. However, linear mixed-effects models revealed no trial-by-trial correlations between pupil dilation and N400 amplitude. These findings suggest that although both measures are sensitive to word frequency, they may reflect independent cognitive processes. In Experiment 2, the effects of word frequency and pupil size were further examined in the context of reading Chinese sentences. As expected, word frequency significantly modulated eye movement indices, with longer first fixation durations, gaze durations, and single fixation durations observed for lower-frequency words, as revealed by linear mixed-effects models. However, neither tonic nor phasic pupil size correlated with these eye movement measures. These results suggest that pupil size may not reliably reflect cognitive processing during natural sentence reading in Chinese. In summary, the findings suggest that pupil dilation provides complementary information to N400 amplitude in Chinese single-word reading, but may play a less prominent role in the context of sentence reading. Future research is needed to further explore the role of pupil size in Chinese reading comprehension. |
