Neural Mechanism Underlying Foreign Language Effect On Decision-making

Accumulating amount of research has provided evidence for the foreign language effect on decision-making,moral judgment,mental imagery and causality bias.Our prior work revealed reduction of the “hot hand” effect by a foreign language during even-probability gambling.However,it remains unclear what are the fundamental mechanisms underpinning the foreign language effect.The present study aims to uncover them by combining behavioral and functional magnetic resonance imaging(fMRI)methods.Forty-one late Chinese-English bilinguals were engaged in an fMRI version of our risky-choice task,which required participants to make decisions between playing and leaving equal-odds bets whilst manipulating language of feedback and outcome value.Their “play” or “leave” decisions for each gamble were analyzed with binary logistic regression.Simultaneously,blood oxygenation level-dependent(BOLD)signals were collected on a 3T GE Discovery MR750 system.Results showed that a reduction of the hot hand effect in the second language context such that when positive game outcomes were presented in English participants subsequently took significantly fewer gambles as compared to the trials in which equivalent feedback was given in Chinese or in which there was no feedback provided.In terms of fMRI data,we first employed one-sample t-tests to examine respectively BOLD responses to Chinese positive,Chinese negative,English positive,and English negative feedback using the no-feedback periods as the baseline.All analyses used a whole-brain approach with a significance threshold of p < 0.05 based on family-wise error correction.We found that the four types of feedback all activated both visual language information processing areas such as bilateral fusiform gyrus and emotionand reward-related areas including bilateral insula,amygdala,caudate,putamen,orbital frontal cortex(OFC)and anterior cingulate cortex.We also used t-tests to measure the main effects of language and valence.While the language main effect did not survive the significance threshold in any area,the valence main effect significantly activated a number of regions.That is,positive relative to negative feedback significantly increased the activity in the brain reward system,notably the putamen,caudate,amygdala,and OFC,and also in emotion regulation areas including the medial prefrontal cortex and anterior cingulate cortex.Furthermore,a flexible factorial model was used to examine the interaction between language and valence,showing significant effects in the left fusiform gyrus and thus suggesting a critical role of this region in language-emotion interplay.Based on the observed effect in the left fusiform gyrus,a functional connectivity analysis was further conducted,revealing distinct language-emotion modulated changes in the connections of the left fusiform gyrus with the right inferior frontal gyrus(IFG)and the right lingual gyrus respectively.Correlation analyses ruled out the impact of language proficiency,frequency of use and age of acquisition on language-induced differences observed at behavioral and neural levels.The analyses also identified a marginally significant correlation of cross-language differences in gambling rates with those in parameter estimates extracted from the fusiform-IFG connection in response to positive feedback.Taken together,the present study provides evidence for the language-dependent valence-specific effects at behavioral as well as neural levels.Both gambling rates and fMRI responses convergently suggest that there are two parallel mechanisms underlying respectively the encoding of positive and negative feedback and subsequent decisions and only the one related to positive feedback is emotion-dependent,in which emotionality differences between the native and foreign languages function for modulation of risky choices.The reduction of risk-taking behavior following positive feedback in English as compared to Chinese,namely the foreign language effect,is likely to be underpinned by a language-emotion-decision neural circuit involving interactions between the right lingual gyrus,the left fusiform gyrus,and the IFG.