Previous research has provided substantial evidence supporting the role of executive control in facilitating metaphor comprehension. However, the neural mechanisms underlying executive control in metaphor processing remain insufficiently explored. In this dissertation, event-related potential (ERP) and standardized low-resolution brain electromagnetic tomography analysis (sLORETA) were employed to investigate the role of executive control in metaphor comprehension in first (L1) and second language (L2). Additionally, potential cross-language differences in bilingual metaphor comprehension across different levels of executive control were examined. Using ERP and sLORETA, Study I and II investigated the effect of executive control in L2 (English) and L1 (Chinese) metaphor comprehension across different familiarity levels, respectively. Results showed individuals with low executive control exhibited more negative amplitudes of N400 and P600 during L1 and L2 metaphor comprehension compared to high individuals. Familiarity modulated the relationship between executive control and L2 metaphor comprehension in both high and low executive control groups, but only in low executive control group for L1. Furthermore, in the low familiar metaphor comprehension, sLORETA analysis revealed stronger activation of the right superior frontal gyrus (SFG) and middle frontal gyrus (MFG) in the low executive control group in L2, while high executive control group exhibited stronger activation of the right middle temporal gyrus (MTG) in L1. These findings suggest that executive control contributes to both L1 and L2 metaphor comprehension and modulated by familiarity. Study III further investigated potential cross-language differences in bilingual metaphor comprehension across different executive control groups using ERP. Results indicated greater executive control influence on L2 than L1, as reflected in N400 and P600 amplitudes. Additionally, the graded N400 effect for L1-L2 metaphors was only observed in individuals with low executive control. These findings suggest that L2 metaphor processing is more susceptible to executive control than L1. In summary, these studies deepen our understanding of executive control's neural mechanisms in metaphor processing and offer new insights into its functional role in bilingual metaphor comprehension.
Publication Details
PhD Thesis Vol. 0 2024-10-24
Jiaqi Zhu
https://jyx.jyu.fi/jyx/Record/jyx_123456789_105853#