Detecting deception via strategic disclosure of evidence.

Abstract

Several decades of research has shown that people are poor at detecting deception. This thesis, based on four empirical studies, aimed at exploring human deception detection accuracy in the context of interrogations. In three of the studies, there was a special focus on the presence of evidence in the interrogation, and how strategic use of this evidence affected the statements of the suspects as well as the accuracy of the lie-catchers. In previous research, the fact that there in real-life situations often exists evidence against a suspect has been neglected. It was expected that it would be beneficial for deception detection to withhold the evidence during the interrogation, and that this would lead to liars contradicting the incriminating information to a higher degree compared to truth tellers. Differences in statement-evidence consistency between liars and truth tellers could then serve as a cue leading to more accurate veracity judgments. In Study I, experienced police officers (N = 30) were set free to conduct interrogations with mock suspects in the manner of their own choice. They also watched a video-taped interrogation conducted by one of their colleagues. Both when interrogating and observing video, the police officers achieved deception detection accuracy levels (56.7%) similar to the level of chance. The aim of Study II was to examine the effects of disclosing the evidence at different stages of the interrogation. It was expected that disclosing the evidence late (vs. early) in the interrogation would provide a better basis for correct veracity judgments. The reason for this was that late disclosure of evidence would make liars and truth tellers differ in terms of statement-evidence consistency. Mock suspects (N = 58) were interrogated by experimenters. Lie-catchers (N = 116) who watched late disclosure interrogations (accuracy 61.7%) significantly outperformed those who watched early disclosure interrogations (accuracy 42.9%). In Study III, police trainees (N = 82) either were or were not trained in strategically using the evidence when interrogating lying or truth telling mock suspects (N = 82). Liars interrogated by trained interrogators were more inconsistent with the evidence compared to liars interrogated by untrained interrogators. Trained interrogators obtained a considerably higher accuracy rate (85.4%) than untrained interrogators (56.1%). In Study IV, the strategies reported by the suspects (N = 82) in Study III were examined. Guilty suspects, to a higher degree than innocent suspects, applied conscious strategies in order to appear truthful. Guilty suspects reported diverse strategies (such as to provide a consistent story or an alibi), while innocent suspects reported the strategy to tell the truth like it had happened, indicating a belief in the visibility of innocence (i.e., they thought that innocence shows). The results of the thesis show that when the evidence is not used strategically during an interrogation, deception detection accuracy is poor. However, when the evidence is us...

Interviewing suspects: examining the association between skills, questioning, evidence disclosure, and interview outcomes

“…In some experimental studies that have favoured a 'late' EDM approach (e.g. Hartwig et al, 2005Hartwig et al, , 2006Sorochinski et al, 2014) the methodologies involved either a somewhat simplistic mock offence or (when the task was more complex) 'suspects' having only a short amount of time to create their story. Neither of these two scenarios may have always particular resonance to reallife.…”

“…For example, several studies have found an association between the revelation of evidence and the gaining of further information (Bull & Leahy-Harland, 2012;Nystedt, Nielsen, & Kleffner, 2011;van der Sleen, 2009), while other (experimental) studies have revealed that certain evidence disclosure strategies have contributed to the rigorous testing of given accounts by mock suspects, and, in turn, the detection of either lies or truth (Dando, Bull, Ormerod, & Sandham, in press;Granhag, Strömwall, Willén, & Hartwig 2012;Hartwig, Granhag, Strömwall, & Kronkvist 2006;Hartwig, Granhag, Strömwall, & Vrij, 2005;Sorochinski et al, 2014). Yet other studies have found that disclosing strong evidence is associated with suspects' confessions (Bull & Soukara, 2010;Cassell & Hayman, 1996;Gudjonsson & Petursson, 1991;Kebbell, Hurren, & Roberts, 2006;Moston, Stephenson, & Williamson, 1992;Sellers & Kebbell, 2009;Soukara et al, 2009;Walsh & Bull, 2012a).…”

“…In contrast, 'late' disclosure involves eliciting the whole story from the suspect, dealing with all potential alibis and potential excuses, before presenting the evidence (see Hartwig et al, 2005;Sorochinski et al, 2014). (For a fuller explanation of these three different strategies, see Bull, 2014).…”

“…They concluded that gradually disclosing evidence may be effective in persuading otherwise reluctant (but very likely guilty) suspects to confess. Earlier, Hartwig et al (2005) found, in their pioneering experimental study, that late disclosure of evidence, rather than early, enabled more liars to be identified by trained 'mock' interviewers. More recently, Sorochinski et al (2013) found in their study that both gradual and late disclosures of evidence were more likely to reveal truth tellers and liars.…”

One Way or Another? Criminal Investigators’ Beliefs Regarding the Disclosure of Evidence in Interviews with Suspects in England and Wales

“…'Gradual' evidence disclosure involves a phased presentation of information/evidence, provided in a 'drip-feed' effect throughout the interview (Dando & Bull, 2011;Granhag et al, 2012). In contrast, 'late' disclosure relates to the gathering of the whole story from the suspect, and dealing with all potential alibis and the like, before presenting the evidence (see Hartwig et al, 2005;2006, Sorochinski et al, in press). …”