Frontiers in Psychiatry | 2019
Digging Further Into the Speech of Liars: Future Research Prospects in Verbal Lie Detection
Abstract
The field of verbal lie detection has grown rapidly in the past decade. Derived by the assumption that lies have different content patterns than do truths, research in this area promotes searching for content criteria to detect them. One prime content-based indicator for deception detection, which stems from the Reality Monitoring (RM) theory (1), is richness in detail. According to RM, truthful memories of actual events originate in perceptual experience and are embedded in the context of time and space. As such, they are expected to include more spatial and temporal contextual attributes (i.e., locations, spatial arrangement of people and objects, times, duration and sequence of events) and perceptual attributes (i.e., what the individual felt, tasted, smelled, heard, or saw when the event took place) than do false memories, which originate in self-generated thought or imagination. Derived from this prediction, the traditional use of richness in detail as an indicator of deception is based on the number of perceptual and contextual details in the interviewee’s accounts. However, as a memory source-monitoring theory, RM does not take into consideration the intention of liars to deceive and consequently cannot explain the full scope of richness in detail in the field of deception (2). In contrast to false memories, where the individual has no intention to deceive but wrongly believes that his/her memory of an event that never happened is truthful, fabricated memories are an outcome of manipulation [and have thus been labeled “self-manipulated memories”; (2)]. Liars frequently attempt to manipulate their fabricated accounts to make them seem truthful (3–5), for example by intentionally adding false perceptual and contextual details (6, 7). Affecting the quantity of the details in their fabricated accounts, such strategic manipulations reduce the diagnostic efficacy of the richness in detail indicator. Yet, in the current paper, we aim to show that the same strategies leave traces on the quality of details. Therefore, we propose that to maximize the potential utility of the richness in detail indicator, it is necessary to dig deeper into the speech of liars, particularly by looking for traces of deception strategies found in the quality of the details. In fact, the Verifiability Approach [VA; (4, 8)] applies this notion.