Metaphor comprehension is a crucial cognitive process, involving the integration of source and target domain features to create a new representation. The Structure Building Framework highlights the role of inhibitory control in filtering irrelevant information and selecting appropriate meanings during this process. Previous research has shown that inhibitory control influences first language (L1) metaphor comprehension, with effects modulated by metaphor conventionality (novel vs. conventional) and context. However, the role of inhibitory control in second language (L2) metaphor comprehension, especially its interaction with conventionality and context, remains less understood. This study addresses this gap by examining how inhibitory control influences L2 metaphor comprehension across varying degrees of conventionality and contextual support. The study's importance lies in its potential to shed light on the cognitive mechanisms underlying L2 metaphor processing and provide valuable insights into the role of executive functions in second language acquisition.

Existing research demonstrates a link between inhibitory control and L1 metaphor comprehension. Studies indicate that individuals with higher inhibitory control perform better on metaphor comprehension tasks, particularly with novel metaphors requiring controlled comparison processes to integrate multiple meanings. The Structure Building Framework suggests that high inhibitory control facilitates the suppression of irrelevant meanings and the construction of cohesive mental representations. However, the role of inhibitory control differs depending on metaphor conventionality: while it aids in novel metaphor comprehension, its impact on conventional metaphors is less pronounced. Context also plays a crucial role; high inhibitory control individuals effectively integrate contextual cues, while low inhibitory control individuals struggle with this integration process. Previous studies have focused primarily on L1 metaphor comprehension, with limited research on L2 metaphor processing. While some research suggests that inhibitory control is involved in L2 metaphor comprehension and that context influences L2 metaphor understanding, the interaction between inhibitory control, conventionality, and context in L2 remains largely unexplored.

This study employed two experiments using a modified flanker task to measure inhibitory control and a semantic judgment task to assess L2 metaphor comprehension. Experiment 1 examined the effect of inhibitory control on L2 metaphor comprehension without context. Participants, 67 Chinese-English bilingual undergraduate students, were divided into HIC and LIC groups based on their flanker task performance. They performed a semantic judgment task on conventional and novel L2 metaphors presented in isolated sentences. Experiment 2 investigated the influence of context. The same metaphors were presented with either supportive or literal contexts, and participants judged the figurative meaning. Materials comprised 60 conventional and 60 novel metaphors in English, along with filler sentences. Metaphors were pre-rated for conventionality, comprehensibility, and aptness to control for confounding factors. Mixed-effects models were used to analyze response times (RTs) and accuracy rates (ACCs) in both experiments, examining the interaction between inhibitory control group, metaphor type, and context.

Experiment 1, without context, revealed that the HIC group responded significantly slower to novel metaphors than the LIC group, while no significant difference was observed for conventional metaphors. This suggests that conventionality modulates the effect of inhibitory control. Experiment 2, with context, revealed a significant three-way interaction between inhibitory control, metaphor type, and context. The HIC group showed faster processing of novel metaphors in supportive contexts compared to literal contexts; conversely, the LIC group showed faster processing of conventional metaphors in supportive contexts. These findings indicate that the facilitative effect of supportive contexts interacts with both inhibitory control and metaphor conventionality. Specifically, in Experiment 1, the chi-square test showed a significant interaction between inhibitory control group and metaphor type (p=0.033). Simple effects analyses revealed the HIC group was significantly slower than the LIC group for novel metaphors (p=0.023), but not for conventional metaphors (p=0.241). In Experiment 2, the analysis of RTs revealed significant main effects of metaphor type (p=0.010) and context (p=0.011), as well as a significant three-way interaction between inhibitory control, metaphor type, and context (p=0.031). Pairwise comparisons revealed that the HIC group was significantly faster on novel metaphors in supportive contexts compared to literal contexts (p=0.013). The LIC group, however, was significantly faster on conventional metaphors in supportive contexts compared to literal contexts (p=0.026).

The results suggest that inhibitory control's role in L2 metaphor comprehension is more complex than in L1, being dynamically modulated by conventionality and context. The negative effect of high inhibitory control on novel metaphors in the context-free condition might stem from the more deliberate processing strategies employed by HIC individuals, involving cross-linguistic mapping and extensive meaning integration. The facilitative effect of supportive contexts on novel metaphors for HIC individuals and conventional metaphors for LIC individuals points to different contextual usage strategies. High inhibitory control allows for efficient integration of relevant contextual information and suppression of irrelevant information, while low inhibitory control leads to reliance on salient information provided by supportive contexts. These findings align with the Structure Building Framework, highlighting the role of inhibitory control in constructing cohesive mental representations. The differences in processing strategies between HIC and LIC individuals are consistent with previous studies showing that high working memory individuals adopt more thoughtful approaches to complex tasks.

This study demonstrates the dynamic and flexible role of inhibitory control in L2 metaphor comprehension, contingent on metaphor conventionality and context. High inhibitory control aids in integrating information from supportive contexts, particularly for novel metaphors, while low inhibitory control facilitates processing of conventional metaphors in supportive contexts. Future studies could explore the effect of inhibitory control on diverse metaphor types and complex contexts, and utilize a wider range of inhibitory control measures.

The study's use of nominal metaphors with simple structures might limit the generalizability of findings to more complex metaphorical expressions in naturalistic contexts. Also, employing only the flanker task to measure inhibitory control may not fully capture the complexities of this executive function; future studies could benefit from incorporating additional inhibitory control tasks.