Three lessons are drawn from this review of the research on indicators of lying. First, there are reliable signs that can be used to detect lies; however, they are complex and numerous. Second, lie detection is best done as a neutral observer. Careful observation is more important than the intent to detect lies. Truth detection and lie detection work best as reflections about observations of behavior, not as qualitative judgments. Third, law enforcement officers and students have both learned to become more efficient lie detectors when they had practice that included feedback. Memorizing a list of behavior factors is not sufficient; practice with feedback is crucial. This was shown in the research conducted by Mann, Vrij, and Bull (2004). They examined the ability of police officers to detect lies and whether it was linked to their degree of experience in actually interviewing criminals. Whereas other studies had measured officers' total length of service, Mann's research measured active interviewing and interrogation practice. Whereas regular police officers often did no better at lie detection than college students (50 percent accuracy), practiced interviewers and interrogators did much better (60-70 percent accuracy). This suggests that the best training in lie detection is extended involvement in interviewing and interrogating suspects. 22 references