Lie detection assessments as evidence in criminal courts

In principle, lies could be detected in three different ways: by measuring people's physiological responses, by analysing their speech content, or by observing their behaviour. Several physiological lie detection tests exist, such as the Relevant–Irrelevant Test, Directed Lie Test, and Guilty Knowledge Test, but the Control Question Test is the most widely used. Several verbal lie-detection methods also exist, including Scientific Content Analysis (SCAN), but Statement Validity Analysis (SVA) is the most widely used test. This chapter discusses the Control Question Test and SVA. It considers how those tests work, which problems are associated with them, and how accurate they are in distinguishing between liars and truth tellers. It also discusses whether these tests meet the criteria that are required for admitting expert scientific evidence in criminal courts, according to the US Supreme Court Daubert decision.