Don’t cry over spilled milk: foreign language attenuates the sunk cost effect

Sunk cost effect, which reflects the greater tendency to continue an endeavour once an investment in money, time, or effort has been made, is a decision-making bias. We conducted three studies to examine the debiasing effect of a foreign language on sunk cost effect. Study 1 failed to prove that participants’ choice of sunk costs differed when they make judgments in a foreign language than in a native language. Foreign language proficiency and binary scale are regarded as important factors influencing this result. Therefore, we conducted study 2 in which we used a more sensitive 6-point scale. The results indicated that foreign language did attenuate the sunk cost effect. Study 3 showed that emotion mediated the relationship between language and sunk cost effect. These findings expand our understanding of how a foreign language affects decision-making bias and the underlying mechanism of this effect.