Discovering Deceit: Applying Laboratory and Field Research in the Search for Truthful and Deceptive Behavior

“Science is the captain, and practice the soldiers”—Leonardo da Vinci da Vinci’s sage observation may be conceptualized as a guide for applied researchers; the most meaningful psychological research addresses an interesting topic with both basic and applied relevance. Once identi fi ed, the phenomenon of interest should be studied both in the lab—offering a high level of internal validity—and in the “ fi eld”, lacking experimental control but offering more realism, and not rushing to scienti fi c judgment based on or the other (Yuille, 1996 , present volume). Subsequently, converging empirical fi ndings from the lab and fi eld should be responsibly applied in the legal context (e.g., Paz-Alonso, Ogle, & Goodman, present volume; Yuille, 1989 ) . One program of research exemplifying these principles is outlined in this chapter: detecting deception. A key role of judges and jurors at trial is to decide whether various witnesses are lying or telling the truth (see Seniuk, present volume). But is it possible to determine accurately whether a witness is providing an honest and accurate version of events, an unintentionally mistaken memory, or lying through his/her teeth? This issue is not trivial; in an adversarial system, most trials feature contradictory testimony by witnesses (see Connolly & Price, present volume; also see Fisher, Vrij, & Leins, present volume, for research focusing on contradictory statements within witnesses). In increasingly common “he said, she said” cases, there is little or no evidence other than con fl icting stories told by a complainant and defendant, and decision-making is guided almost entirely by credibility assessments (e.g., Porter, Campbell, Birt & Woodworth, 2003 ) . For example, the judge in the Air India mass murder case ( R. v. Malik & Bagri , 2005 ) concluded that the case was reduced to a credibility contest: “... the determination of