Lying in a native and foreign language.

This study explores the interaction between deceptive language and second language processing. One hundred participants were asked to produce veridical and false statements in either their first or second language. Pupil size, speech latencies, and utterance durations were analyzed. Results showed additive effects of statement veracity and the language in which these statements were produced. That is, false statements elicited larger pupil dilations and longer naming latencies compared with veridical statements, and statements in the foreign language elicited larger pupil dilations and longer speech durations and compared with first language. Importantly, these two effects did not interact, suggesting that the processing cost associated with deception is similar in a native and foreign language. The theoretical implications of these observations are discussed.