The language of lies: Behavioral and autonomic costs of lying in a native compared to a foreign language

Research on trustworthiness indicates that non-native speakers are perceived as less trustworthy than native speakers. Research investigating whether people do indeed lie less well in a non-native language is, however, scarce and yielded inconsistent results. Two opposing predictions are possible. Based on the idea that lying is more demanding than truth telling, the cognitive load account predicts that speaking a foreign language imposes additional cognitive load and thereby hampers lying. Based on the idea that lying is emotionally arousing and that communication in a non-native language is perceived as less emotional, the emotional distance account predicts that speaking a foreign language facilitates lying. In three experiments, participants were asked neutral and emotional questions both in their mother tongue (German) and in a foreign language (English). Depending on a color cue, questions had to be answered sometimes truthfully and sometimes deceptively. Results across all experiments consistently revealed smaller reaction time (RT) differences between lying and truth telling in the foreign compared to the native language condition, which was mostly driven by prolonged truth responses. There were neither differences in this language modulation between emotional and neutral questions nor in autonomic responses. Results could be explained by the antagonistic effects of cognitive load and emotional distance on lying, and suggestions are made how further research may disentangle those effects. Importantly, the observation that foreign language use hampers truth telling could explain the perceived lower trustworthiness of foreign language speakers and education about this effect may help to reduce such a bias. (PsycINFO Database Record