The Cognitive Neural Mechanism Of Foreign Language Effect On Rational Decision

A growing body of research has reported that bilinguals tend to make more rational decisions when the information is presented in their second language（L2）compared to their first language（L1）,which is so-called “foreign language effect”.However,previous studies have respectively examined how emotional involvement and cognitive load affect decision-making,which not only neglects the interaction effect between these two factors,but does not focus on the potential interference with foreign language effect on rational decision process.Therefore,this study conducts a cross-task paradigm in which the lexical-semantic task and gambling task intersect.The cognitive load is manipulated by a lexical-semantic task with changing difficulty.Specifically,traditional characters in L1（Chinese）and words with capital letters in L2（English）carried with negative and neutral emotion valence are used to increase the cognitive load.Participants made a judgement about whether the negative/neutral words presented in L1 or L2 are true words at first,and then decided whether to make a risky decision in a gambling game（50% win,50% loss）.The optimal choice is distinguished by gambling choice with Kelly criterion.Experiment 1 uses electroencephalography（EEG）technology with a high time-resolution to record the participants’ gambling performance in a single language context.The results showed that after lexical decisions on high cognitive load（only in rational choices）,P3 in L1 was stronger in negative words compared to neutral words.However,a reverse effect was found in L2 with a more robust P3 on neutral words compared to negative words.Critically,on the high cognitive load condition,the rationality rate of decision-making decreased at L1 and increased in L2 as the P3 effect enhanced in negative words（vs.neutral words）.The results further revealed that the increased Granger causal strength predicted more rational choices in the L2 high-load negative condition.Experiment 2 employs a functional magnetic resonance imaging（f MRI）technology with a high spatial-resolution to record the gambling performance in a single language context.The experimental procedure is same as experiment 1.The results showed that after processing a neural word under high cognitive load,the cingulate gyrus was greater activated in the rational choices.Especially,the cingulate gyrus showed this activation pattern only emerged in L2 context.The functional connectivity analysis showed that the connectivity of the dorsal striatum-cerebellum and cerebellum-left middle occipital gyrus were stronger in negative condition under heavy cognitive load.The main conclusions are as follows:1.The P3 effect can be regarded as an indicator about rational strategy calculation.Although heavy cognitive load in L2 context weakens the involvement of negative emotion,the excessive load will impair people’s calculate ability about risk evaluation,reducing the rational choices.2.The activation of the cingulate gyrus decreases in L2 negative condition under high cognitive load,but there is no difference in L1 context.This result suggests that the interaction between cognitive load and emotion may exhibit different neural patterns in different language contexts.Moreover,the functional connectivity difference between highand low-load in negative conditions revealed that the interaction of cognitive load and emotion plays a crucial role in rational decision-making.In conclusion,the present study found that the interaction between cognitive load and emotion would impact individual’s rational decision-making,which is modulated by language context.Furthermore,this study systematically revealed the neural mechanism of bilingual’s rational decision-making affected by languages,emotion and cognitive load.