Detecting deception in second-language speakers

Abstract

It is currently unknown how lie detection accuracy is affected when someone is speaking in his or her second language. We examined whether language proficiency had an impact on lie detection. We hypothesized that when judging the veracity of second-language speakers, participants would be better able to discriminate between truth- and lie-tellers and would have bias toward picking ‘lying’ since they may display cues associated with lying when communicating.We collected video footage of native- and second-language English speakers who lied or told the truth about a transgression. Undergraduate students (N = 51) then judged the veracity of these clips and indicated how confident they were in their ratings. Participants were most accurate and confident when judging native-language truth-tellers. In addition, participants were more likely to exhibit a truth-bias when observing native-language speakers, whereas they were more likely to exhibit a lie-bias when viewing second-language speakers. Implications for the justice system will be discussed.