Witness reports are vital for solving crime, yet police and other investigators receive relatively little training on how to interview witnesses and victims. As a consequence, police interviewers often elicit less information from witnesses than is potentially available. We describe here an interview protocol, the Cognitive Interview (CI), based on scientific principles of cognitive psychology, and review the research which shows that the CI reliably elicits more witness information than typical police interviews. These findings are then extended to several real-world criminal investigations in which the CI elicited new, critical information. Principles of cognitive psychology can also be used to detect deception, by exploring the different thought processes of liars and truth-tellers. Finally, we show how incorporating these differences between liars and truth-tellers into an interview protocol can improve investigators’ abilities to detect deception.
