Detecting false intentions with unexpected questions

To test potential differences, we used an experimental set-up where liars planned a criminal act (i.e., installing a virus on a network computer) and truth-tellers a non-criminal act (i.e., installing a new presentation program “SlideDog” on a network computer). Before they could carry out these acts, a confederate intercepted the participant and interviewed them about their intentions and the planning phase by using both anticipated and unanticipated questions.

Liars used a cover story to mask their criminal intentions while truth-tellers told the entire truth. In contrast to our hypotheses, we did not find any evidence that liars and truth-tellers differed in plausibility or detailedness. Furthermore, results showed that asking unanticipated questions resulted in more details than anticipated questions and this effect was driven by temporal details only.