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Most theories of lie detection assume that lying increases cognitive load, resulting in longer response latencies during questioning. However, the studies supporting this theory are typically laboratory-based, in settings with no specific validity in security contexts. Consequently, using virtual reality (VR), we investigated how response latencies were influenced in an ecologically valid environment of interest to security professionals. In a highly realistic airport security terminal presented in VR, a security officer asked participants yes/no questions about their belongings. We found that liars actually responded more quickly to questions on which they were lying than to questions on which they were telling the truth. A control group, who answered the same questions but were not lying, answered equally quickly for all questions. We argue that this decrease in response time is possibly an unconscious reaction to questions on which individuals must answer deceptively. These results call into question the generalizability of previous research and highlight the importance of ecological validity when researching lie detection. These findings also uncover a new potential tool for enhancing lie detection in real-world scenarios.

In recent years researchers have started to focus on lying about intentions (Granhag, 2010). In the present experiment participants were interviewed about their forthcoming trip. We tested the hypothesis that liars (N=43) compared to truth tellers (N=43) would give fewer details to unexpected questions about planning, transportation and the core event, but an equal amount or more detail to expected questions about the purpose of the trip. We also tested the hypothesis that participants who had previously experienced the intention (i.e., they had made such a trip before) would give more detail than those who had never experienced the intended action. The unexpected question hypothesis was supported, whereas the previous experience effect only emerged in interactions. The benefit of using different types of questions for lie detection purposes is discussed., (Copyright © 2012 Elsevier B.V. All rights reserved.)