Baselining as a Lie Detection Method

Abstract

For entirely valid reasons, practitioners urge researchers to develop within-subjects lie detection methods. This article highlights some problems with the existing and popular nonverbal baseline lie detection method and with the use of the Validity Checklist in SVA. The article further suggests how verbal within-subjects lie detection methods can be introduced in interview settings by implementing verbal lie detection interview protocols designed in recent years. The article concludes that these within-subjects methods do not provide the ultimate solution as clear cut-off scores cannot be established, but they are a step forward in verbal lie detection.

Using unexpected questions to elicit information and cues to deceit in interpreter‐based interviews

“…Second, we could examine the proportion of cues to truthfulness, that is, the proportion of complications, complications/ (complications + common knowledge details + self − handicapping strategies, which is a within-subjects measure. Within-subjects measures are preferred by practitioners (Vrij, 2016) and scholars (Nahari, in press;Nahari & Pazuelo, 2015;Nahari & Vrij, 2014), amongst other reasons, because it creates the opportunity to design cut-off scores rules (e.g., "A statement is considered to be truthful when it has more complications than common knowledge details and self-handicapping strategies combined").…”

Using baseline to diagnose internal states? Listen closely

“…For example, in the present study, 20% of participants' diagnoses were related to deception, despite no explicit instructions to judge veracity. Given that only 14% of those judgements coincided with any internal states, it might make sense to incorporate methods to reliably elicit baseline‐relevant cues to deception—for example, by implementing questioning techniques designed to induce and leverage cognitive load (e.g., see Vrij, )—or reduce the extent to which veracity is judged using baselining processes.…”

“…This practice is commonly advocated by programs that train professional investigative interviewers (e.g., see Inbau, Reid, Buckley, & Jayne, ; U.S. Department of the Army, ). However, it is unclear whether the practice, as currently trained, is valid (e.g., see Vrij, ). Little empirical knowledge exists about the mechanisms underlying the processes interviewers use to establish and monitor baselines to determine any interviewee internal state, let alone veracity.…”

Science‐based interviewing: Information elicitation

“…For example, the plausibility and number of details offered when the subject answers a question that is likely to have been anticipated might be compared with those same factors when he answers a question that is likely to have been unanticipated (Leins, Fisher, Vrij, Leal, & Mann, ; Vrij & Ganis, ; Warmelink, Vrij, Mann, Jundi, & Granhag, ). Thus, “baselining” might be accomplished by first asking anticipated questions, then unanticipated questions (Vrij, ). The same comparison could be made for when a subject is telling a story forward with when he is asked to tell it in reverse (a tactic that itself increases cognitive load)—in addition, if this story is true, telling it in reverse order is likely to lead the subject to remembering more details (Vrij et al, ).…”

“…A better tactic is to compare verbal behaviours before and after deploying science-based tactics to elicit more information and/or cues to deception (Vrij, 2016). For example, the plausibility and number of details offered when the subject answers a question that is likely to have been anticipated might be compared with those same factors when he answers a question that is likely to have been unanticipated (Leins, Fisher, Vrij, Leal, & Mann, 2011;Vrij & Ganis, 2014;Warmelink, Vrij, Mann, Jundi, & Granhag, 2012).…”