過去事件相關電位的研究顯示：名詞和動詞的差異可反應在P200和N400。該研究的目標是找出中文名詞動詞語意差異的神經生理指標。三個實驗中，我們共同操弄中文雙字詞的具體度和詞類，同時記錄腦電波。實驗一採用具體度評分作業，結果顯示P200會被詞類效果影響，意即動詞比名詞更容易引發更正向的P200，但只達邊緣顯著。N400被具體度效果影響，而且具體度的處理在名詞和動詞有不同的敏感度，敏感度的差異同時反應在N400振幅的大小和出現的時間點。實驗二採用詞彙判斷作業，名詞和動詞在N400都有具體度效果，但動詞N400的振幅比較小。和實驗一動詞沒有在N400得到具體度效果相較，實驗二的結果表示，動詞具體度處理可能在詞彙層次更加明顯。實驗三採用語意相關度判斷作業，結果發現和實驗一結果類似：P200邊緣顯著被詞類效果影響。另外N400，在名詞才有具體度效果，在動詞則是邊緣顯著。綜合三個實驗的結果，具體度的處理在名詞比較顯著跟穩定，但在動詞則會受作業需求而改變。詞類、具體度、和作業的交互作用，使我們認為名詞和動詞間的語意差異不能完全被具體度解釋。Previous ERP studies have demonstrated the difference between nouns and verbs reflected in P200 and N400.The goal of this research is to identify the neuro-physiological index of semantic segregation between Chinese nouns and verbs. In three experiments, we manipulated the concreteness and word class of Chinese disyllabic words while ERP recording was simultaneously applied throughout the task. In Experiment 1, we employed the concreteness rating task. The results demonstrated that P200 was marginally modulated by the word class effect, which showed a more positive P200 for verbs than nouns. In contrast, N400 was modulated by the concreteness effect. Moreover, the different sensitivity to concreteness processing between nouns and verbs was revealed both in the magnitude and the latency of N400. In Experiment 2, we used the lexical decision task. The concreteness effect in N400 for nouns and verbs were both obtained, though the amplitudes were smaller in verbs. Compared with failure of finding the concreteness effect in N400 for verbs in Experiment 1, such finding implied that concreteness processing for verbs might be more pronounced at the lexical level. In Experiment 3, we used the semantic relatedness judgment task and found that P200 was marginally modulated by the word class effect as in Experiment 1. Furthermore, the concreteness effect in N400 was modulated in nouns but only marginally modulated in verbs. Based on these results, concreteness processing across three experiments is pronounced and reliable in nouns but is task-dependent in verbs. We argue that the noun-verb difference at the semantic level cannot be fully explained by concreteness.
