Guilty and innocent suspects’ strategies during police interrogations

Abstract

Deception detection has largely failed to investigate guilty and innocent suspects’ strategies. In this study, mock suspects (n=82) were interrogated by police trainees (n=82) who either were or were not trained in the technique to strategically use the evidence (the SUE technique). Analyses revealed that guilty suspects to a higher degree than innocent suspects applied strategies in order to appear truthful. Guilty suspects reported diverse strategies, while innocent suspects reported the strategy to tell the truth like it had happened, indicating a belief in the visibility of innocence. The realism in the suspects’ expectation about how their veracity was judged was largely dependent on the way in which they had been interrogated. The truth-telling suspects who were interrogated according to the SUE technique were optimistic about being judged as truthful; this optimism was warranted as the vast majority of them were classified as truthful. The SUE technique seems to help (a) spotting guilty suspects without them being aware of it and (b) spotting innocent suspects, and they become aware of it. That innocent (but not guilty) suspects can read how the interrogator views them is advantageous for the investigative process.     

Increasing Cognitive Load to Facilitate Lie Detection: The Benefit of Recalling an Event in Reverse Order

In two experiments, we tested the hypotheses that (a) the difference between liars and truth tellers will be greater when interviewees report their stories in reverse order than in chronological order, and (b) instructing interviewees to recall their stories in reverse order will facilitate detecting deception. In Experiment 1, 80 mock suspects told the truth or lied about a staged event and did or did not report their stories in reverse order. The reverse order interviews contained many more cues to deceit than the control interviews. In Experiment 2, 55 police officers watched a selection of the videotaped interviews of Experiment 1 and made veracity judgements. Requesting suspects to convey their stories in reverse order improved police observers' ability to detect deception and did not result in a response bias.     

Innocent of the crime under investigation: suspects’ counter-interrogation strategies and statement-evidence inconsistency in strategic vs. non-strategic interviews

ABSTRACT

The study examines the counter-interrogation strategies applied by mock suspects (N?=?94), who are innocent of a mock crime under investigation but who were present at the scene, for different reasons, at around the time the crime occurred. Half were present at the crime scene to carry out a lawful act, the other half to carry out an unlawful act. Furthermore, this study examines the effect of the Strategic Use of Evidence (SUE) technique as a strategic interviewing technique (vs. a non-strategic technique), on suspects’ statement-evidence inconsistencies. Participants were randomly assigned to the two interview conditions (strategic vs. non-strategic) and were interviewed as suspects of a crime, which none of them had committed. The results show that the most commonly used counter-interrogation strategy in both groups was to be honest. However, 26.1% of the innocent suspects, performing an unlawful act, reported the strategy to be deceptive. In addition, the statements of suspects executing an unlawful act were significantly more inconsistent with the evidence in the strategic than the non-strategic interview condition. The increased statement-evidence inconsistency rates potentially put these suspects at risk of being assessed as guilty of a crime they did not commit.     

‘I'm a photographer,not a terrorist’: the use of photography to detect deception

When planning large-scale incidents or bombing campaigns, terrorists often conduct reconnaissance research to identify key targets. This may include taking photographs of potential target locations. Identifying an effective real-time method to distinguish between genuine photographers and those with more sinister intent may be beneficial for law enforcement and security agencies. Participants took photographs in a public place with a genuine intent (truth tellers) or sinister intent (liars). After taking these photographs, the participants were approached by an undercover interviewer (a mime artist) who asked them whether he could see the photographs. Later, the participants discussed their photographs in a formal interview. First, liars were less cooperative in their interaction with the undercover interviewer than truth tellers. Second, in the formal interview, liars mentioned some security features that appeared in the photographs more than truth tellers. The findings suggest that ‘using photographs to detect deception’ is a subject that could prove important to explore to benefit forensic and counter-terrorist practice.     

Effects of preconceptions on deception detection and new answers to why lie-catchers often fail

Abstract

This study investigated the extent to which crediting and discrediting background information, given to observers before they watched three video-taped interviews with the same witness, affected their veracity judgments. Our analyses show that the observers' distribution of truth/lie-judgments were more affected by crediting than discrediting background information. We also mapped the subjective cues given to justify the truth/lie-judgments, and found that the most frequently used cue was whether or not the three statements were consistent over time. In addition, our analysis revealed two types of inter-observer disagreements. One type referred to how different cues were perceived (e.g., forty observers perceived the three statements as being inconsistent over time while an equal number perceived the same three statements as being consistent over time). The second type referred to how different cues were used (e.g., the fact that the witness was perceived as not being confident in his testimony worked against him equally as often as it worked for him).     

Who should I look at? Eye contact during collective interviewing as a cue to deceit

Pairs of liars and pairs of truth tellers were interviewed and the amount of eye contact they made with the interviewer and each other was coded. Given that liars take their credibility less for granted than truth tellers, we expected liars to monitor the interviewer to see whether they were being believed, and to try harder to convince the interviewer that they were telling the truth. It was hypothesised that this monitoring would manifest itself through more eye contact with the interviewer and less eye contact with each other than in the case of truth tellers. A total of 43 pairs of participants took part in the experiment. Truth tellers had lunch in a nearby restaurant. Liars took some money from a purse, and were asked to pretend that instead of taking the money, they had been to a nearby restaurant together for lunch. Pairs of liars looked less at each other and displayed more eye contact with the interviewer than pairs of truth tellers. The implications of these findings are discussed.     

The occurrence of eye blinks during a guilty knowledge test

Abstract

In the present experiment we examined whether eye blinks could discriminate between guilty and innocent examinees in a Guilty Knowledge Test (GKT). Based on the assumption that guilty examinees would experience more cognitive load when responding to the key items than to the control items, we hypothesized that they would display fewer eye blinks during the key items than during the control items. For innocent examinees, responding to the key and control items should be equally demanding, and no differences in eye blinks between key and control items were expected. A total of 26 participants took part in an experiment where 13 guilty examinees committed a mock theft (of an exam paper) and the remaining 13 innocent examinees went on with their normal business. All participants underwent a GKT whereby their eye blinks were measured. Both guilty and innocent examinees displayed the pattern of eye blinks that we predicted. The implications of the findings are discussed.     

Detecting Deception Via Strategic Disclosure of Evidence

Deception detection research has largely neglected an important aspect of many investigations, namely that there often exists evidence against a suspect. This study examined the potentials of timing of evidence disclosure as a deception detection tool. The main prediction was that observers (N = 116) would obtain higher accuracy rates if the evidence against the suspects (N = 58) was presented in a late rather than early stage of the interrogation. This prediction was based on the idea that late evidence disclosure would trigger lack of consistencies between the liars’ stories and the evidence; this could be used as a cue to deception. The main prediction received support. Late disclosure observers obtained an overall accuracy of 61.7%, compared to 42.9% of Early disclosure observers. Deceptive statements were identified with high accuracy (67.6%) in Late disclosure, indicating that the technique in this form is beneficial mainly for pinpointing lies.