Deception evolved as a fundamental aspect of human social interaction. Numerous studies have examined behavioral cues to deception, but most have involved inconsequential lies and unmotivated liars in a laboratory context. We conducted the most comprehensive study to date of the behavioral consequences of extremely high-stakes, real-life deception--relative to comparable real-life sincere displays--via 3 communication channels: speech, body language, and emotional facial expressions. Televised footage of a large international sample of individuals (N = 78) emotionally pleading to the public for the return of a missing relative was meticulously coded frame-by-frame (30 frames/s for a total of 74,731 frames). About half of the pleaders eventually were convicted of killing the missing person on the basis of overwhelming evidence. Failed attempts to simulate sadness and leakage of happiness revealed deceptive pleaders' covert emotions. Liars used fewer words but more tentative words than truth-tellers, likely relating to increased cognitive load and psychological distancing. Further, each of these cues explained unique variance in predicting pleader sincerity.

In this paper, we provide our view of the current understanding of high-stakes lies often occurring in forensic contexts. We underscore the importance of avoiding widespread pitfalls of deception detection and challenging prevailing assumptions concerning strategies for catching liars. The promise and limitations of each of non-verbal/body language, facial, verbal/linguistic, and physiological channels in detecting deception are discussed. In observing the absence of a single cue or behavioural channel that consistently reveals deception, a holistic approach with concurrent attention to multiple channels of a target's behaviour (ideally videotaped for review) and changes from baseline behaviour is recommended whenever possible. Among the best-validated cues to be considered together include: illustrators, blink and pause rate, speech rate, vague descriptions, repeated details, contextual embedding, reproduction of conversations, and emotional 'leakage' in the face. While advocating a reliance on empirical evidence, we observe that few studies of high-stakes deception yet have been conducted. Further, some manifestations of lying are highly idiosyncratic and difficult to address in quantitative research, pointing to the need for keen observation skills, and psychological insight. A recurring theme is the need for the field to devise innovative approaches for studying high-stakes lies to promote ecological validity. Ultimately, such work will provide a strong foundation for the responsible application of deception research in forensic and security settings.

There is little support for the long-standing assumption that judges and jurors can accurately assess credibility. According to Dangerous Decisions Theory (DDT; Porter & ten Brinke, Legal and Criminological Psychology, 14, 119Á134, 2009), intuitive evaluations of trustworthiness based on the face may strongly bias the interpretation of subsequent information about a target. In a courtroom setting, the assessment of evidence provided by or concerning a defendant may be fundamentally flawed if its interpretation is influenced by an initial, spontaneous assessment of trustworthiness. In an empirical test of DDT, participants were presented with two vignettes describing major or minor crimes, accompanied by a photograph of the supposed defendant, previously rated as highly trustworthy or untrustworthy in appearance. Participants evaluated culpability following the presentation of evidence in each case. Participants required less evidence to arrive at a guilty verdict and were more confident in this decision for untrustworthyappearing defendants. The current evidence supports DDT and has implications for legal decision-making practices.