Summary: Should Lie Detection Be Admissible In Court

Should Lie Detection be Admissible in Court?
A Review of Literature

Abstract

Typical deceptive behavior does not exist and there are no perfect methods for deception using Behavioural or content analysis indicators. This report aims at critically evaluating psychological research on Lie Detection procedures. The report focuses on Behavioural indicators of deception with explicit reference to Ekman’s Emotion Theory (1992) and the common verbal and non-verbal cues to deception. The report goes on to describe Content Analysis techniques with direct reference to Criterion-Based Assessment (CBA) and Statement Validity Analysis (SVA) and their success rates as Lie Detection methods. The report outlines many
Ekman (1992) outlines the problems associated with detecting lies. These problems include, the complex nature of the task of monitoring a liar’s behavior. It is extremely difficult to keep track of all aspects of a liar’s behavior, i.e their speech, facial expressions, voice expression, and all bodily movements and as a consequence, lie detectors may overlook some critical cues to deception (Ekman 1992). Also the indicators of emotion can be very difficult to interpret, as emotions are inaccurate indicators of deceit (Ekman, 1992). Ekman also argues that deception can result in differing emotions and the strength of the emotion is dependent on the personality of the liar and the context and circumstances of the lie. These emotions may in turn influence a liar’s non-verbal behavior and liars may attempt to control their behaviours in order to avoid getting caught. This may lead to a liar over controlling themselves and thus making their behavior look rehearsed, rigid and their speech too smooth, thus making non verbal behavior much more difficult to control than verbal
Content indicators of deception involve examining the content of speech in order to ascertain whether deception is taking place. By examining the language and associated verbal processes, some clues about detecting deception could be revealed. The Statement Validity Assessment (SVA) was developed in Germany to determine the credibility of certain content. Undeutsch (1992) was one of the pioneering psychologists and advocate of the Statement Validity Analysis (SVA).
SVA is accepted in a number of European legal systems, however not in UK courts. Opinion about SVA is divided in the USA but has still been used in the courtroom in the US.
SVA consists of two major components, including Criterion Based Content Analysis (CBCA) and the Validity Checklist. Usually, a semi-structured interview is conducted in order to obtain the content to be assessed. The content analysis relies heavily on the “Undeutsch hypothesis” which argues that a statement that comes solely fro memory of an actual experience is extremely different in content and quality from a statement that is fictitious and untruthful (Undeutsch, 1987). The actual process of analyzing content involves trained evaluators to judge the presence of absence or 19 criteria. The presence of each criterion strengthens the hypothesis that the account is based on genuine experience,