You Must Be Lying Because I Don't Understand You: Language Proficiency and Lie Detection

We examined the impact of interviewees' language proficiencies on observers' lie detection performance. Observers (N = 132) were randomly assigned to make deception judgments about interviewees (N = 56) from Four proficiency groups (i.e., native, advanced, intermediate, and beginner English speakers). Discrimination between lie-and truth-tellers was poorest when observers judged beginner English speakers compared to interviewees from any other proficiency group. Observers were also less likely to exhibit a truth-bias toward nonnative than native English speakers. These results suggest that interviewing individuals in their nonnative languages can create inequalities in the justice system.