• Korean Journal of Forensic Psychology
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• v.11 no.3
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• pp.349-370
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• 2020

This study was to test the effects of unanticipated questions on the number of general and verifiable details. In addition, the number of verifiable details would discriminate truth-tellers and liars more accurately than the number of general details. In a 2(Veracity: truth vs. lie) X 2(Question type: Expected questions vs. Unexpected questions) mixed-design study, truth tellers(N=40) were asked to visit a cafe on campus and liars(N=40) were told to fabricated a story as if they visited the cafe. Then, participants were interviewed about their trip to the cafe and asked four questions(two anticipated questions: 'report the trip in detail', 'describe the place'; two unanticipated questions: 'recall in reverse order', 'report verifiable details'). Each participant's statements were transcribed and coded by trained graduate students for the number of general details and verifiable details. The results showed that truth-tellers mentioned significantly more general details than liars regardless of the question type. On the contrary, there was no significant difference between liars and truth-tellers in the number of verifiable details. High percentages of truth-tellers(62.5%) and liars(80.0%) were classified correctly based on the number of general details whereas only 45.0% of truth tellers and 62.5% of liars were accurately classified by the number of verifiable details. Liars were found to speak more words when asked to provide verifiable details compared to a general open question, but the number of general details did not seem to increase accordingly. The limitations of this study and future research directions were discussed.