The effect of foreign language speaking anxiety on the quality of verbal interaction: A fNIRS-based hyperscanning study

Foreign language speaking anxiety is one of the important factors affecting foreign language communication. Fear of negative evaluation is the key factor that induces foreign language speaking anxiety. Many studies have found that foreign language speaking anxiety can negatively affect the quality of verbal interaction through questionnaires and behavioral methods. Yet, few have investigated the brain mechanism of such influence. Therefore, we set up real English communication scene and used fNIRS (functional near-infrared spectroscopy) hyperscanning technique to further investigate relative brain mechanism. A total of 126 Chinese college students were recruited for two experiments. Participants were randomly paired (participant 1 and participant 2) and were asked to finish two storytelling tasks (English vs. Chinese) in turn in both experiments, with fNIRS recording their brain activities simultaneously. Specifically, 24 sequentially numbered pictures formed a complete story, participant 1 received pictures with odd numbers, and participants 2 received pictures with even numbers. During the task, one participant would tell the story of the current round, while the other need to listen carefully, and then both of them would complete the foreign language speaking anxiety scale and continued the story. The turn-taking process went on till the end of the story. The interaction quality was evaluated by two experimenter assistants on a seven-point Likert scale. In Experiment 2, participants were informed in advance that they will be evaluated after the task. This is the only difference between the two experiments, which aimed to rise participants' fear of negative evaluation. Through this process, we intended to explore the effect of external evaluation on the degree of foreign language anxiety on behavior and neural levels. Two experiments obtained consistent results: (1) the participants had significant foreign language speaking anxiety in the English task (compared to Chinese), and their verbal interaction quality was also lower; (2) it was found that the Interpersonal Neural Synchronization (INS) of the left supramarginal gyrus and the left middle temporal gyrus was significantly weakened in each pair of participants in the English task. And weakened INS was also found in the left frontal pole; (3) in the English task, the INS of the left supramarginal gyrus was significantly negatively correlated with foreign language speaking anxiety, and significantly positively correlated with the self-rated verbal interaction quality. Foreign language speaking anxiety affected the quality of verbal interaction through a partial mediating effect of the INS of the left supramarginal gyrus; (4) external evaluation caused higher anxiety but didn't influence the interaction quality. The above consistent results also show that even with the addition of an evaluation component, the effects of foreign language speaking anxiety on verbal interaction quality on behavioral indicators and INS remain unchanged. The results of this study suggests that foreign language speaking anxiety negatively affected the INS of brain regions involved in language and theory of mind. Our findings provide evidence of neural synchronization for understanding foreign language anxiety and verbal interaction and provide a theoretical basis for relieving foreign language speaking anxiety and improving foreign language communication quality.