Recent studies show that people exhibit a reduced decision bias in a foreign language relative to their native language. However, the underlying mechanism remains unknown. Using functional magnetic resonance imaging (fMRI) combined with an even-probability gambling task in which gambling feedback was presented in either a native language or a foreign language after each decision, we assessed the neural correlates of language modulated behavioral changes in decision making. In both foreign and native language contexts, participants showed a behavioral pattern resembles the Gambler's fallacy that losing a gamble leads to more betting than winning a gamble. While there was no language difference in gambling, bilateral caudate and amygdala gain signals were exaggerated by foreign language in relative to native language, suggesting that foreign language enhanced neural responses to rewards. Moreover, the individual difference in foreign language-induced Gambler's fallacy-like decision bias was associated with activation in the right amygdala and ventromedial prefrontal cortex, as well as functional connectivity between right amygdala and right putamen/right posterior insula. Our results confirm that outcome processing in emotion-related regions may underlie individual differences in foreign language effects in judgment and decision making
