Trial by polygraph: Scientific and juridical issues in lie detection

The present article examines two methods of polygraph‐assisted lie detection: the Control Question Technique (CQT) and the Guilty Knowledge Technique (GKT). It presents the rationale for both, arguing that only the latter is well grounded in psychological theory. It then surveys the empirical support for claims of the polygraph's ability to detect deception, arguing that such support often comes from studies that are methodologically flawed by contamination of various sorts—especially studies of the CQT. The article then explores the legal implications of introducing polygraph test results, as presently gathered, into the criminal courtroom.