Mapping Truth and Lies: A Forensic Linguistic Analysis of Verbal and Non-Verbal Cues in Student Interviews

Abstract

This study is the preliminary stage of a series of research projects attempting to develop a lie detection model in student interviews using a forensic linguistic approach. In this study, researchers focused on the differences between truth-telling and lying, as seen from the discourse and non-verbal cues. The data were taken from audio and video recordings of interviews with 20 students who were asked to draw two types of lots. The first draw required the students to either (1) take the envelope and the money inside it or (2) leave the envelope. The second draw required the students to either (1) tell the truth or (2) tell lies during the entire interview session. They were not allowed to show their draw results to anyone, until the end of the interview sessions. The researchers then analysed the discourse and non-verbal cues of the interview results. The theoretical framework used includes the Discourse Open-ness Theory (Fraser, 1990) to analyse the use of discourse markers that provide clues related to honesty or deception in conversation. The Illusion of Honesty Theory (Ekman, 2001) identifies non-verbal cues such as eye contact, gestures, and postures that are often associated with lying. Vrij’s Deception Theory (2008) introduces language strategies commonly used in lying and supports a deeper analysis of the verbal and non-verbal elements found in dishonest interactions. A forensic linguistic approach (Coulthard & Johnson, 2007) is applied to examine sentence structures and other linguistic features that often emerge in deceptive communication. The results of this study show that inconsistent answers, evasions, short and less detailed responses, longer response times, minimal eye contact, rigid or frequently shifting body positions, and nervous smiles are all indications of lies. In contrast, detailed, longer, and consistent responses, direct eye contact, and relaxed posture indicate truth-telling.