Deception among pairs: “Let's say we had lunch and hope they will swallow it!”

Deception research has neglected the fact that legal-workers often have to try to detect deceit on the basis of statements derived from pairs of suspects, each having been interrogated repeatedly. To remedy this shortcoming we conducted a study where each member of 10 truth-telling pairs and 10 lying pairs was interrogated twice about an alibi. One hundred and twenty undergraduate students were enrolled as lie-catchers. The main findings were that (a) overall deception detection accuracy was modest; (b) lie-catchers given access to a large number of statements did not outperform lie-catchers given access to a lesser number of statements; (c) when asked to justify their veracity assessments the most frequently reported cue was ‘consistency within pairs of suspects’; (d) all cues to deception were of low diagnostic value. Psycho-legal aspects of integrating sequential information in deception detection contexts are discussed.     

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).     

A “weapon focus” effect in children

In this paper we examined beliefs about deception held by legal professionals. Three groups of presumed expert lie-catchers were investigated: police officers ( n =104), prosecutors ( n =158), and judges ( n =251). The experts' beliefs about deception were remarkably inconsistent with the general pattern resulting from studies mapping actual cues to deception. For example, a majority of police officers believed there is a strong relationship between (a) deceptive behaviour and gaze aversion and (b) deceptive behaviour and an increase in body movements. The scientific literature does not support this view. Furthermore, all three professional groups believed that truthful consecutive statements are more consistent than deceptive, and that it is easier to detect deception in interactive than non-interactive contexts. Research on deception shows the opposite. For five of the seven investigated items we found significant between-group differences. Both the genesis and the implications of these differences are discussed. Judging from self-ratings, the presumed experts admitted knowing close to nothing about scientific research on deception.     

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.     

Detecting deception in suspects: verbal cues as a function of interview strategy

Research on deception has consistently shown that people are poor at detecting deception, partly due to lack of consistent cues to deception. This research focuses on eliciting verbal cues to deception when questioning suspects who deny crime and how such cues differ due to type of questioning. An experiment examined verbal differences between innocent and guilty mock suspects (N=96) as a function of veracity and interview style (Free recall, Probes, or Free recall plus Probes). Guilty (vs innocent) suspects omitted more crime-relevant information and their statements were more likely to contradict the evidence, showing that statement–evidence inconsistency was a cue to deception. This cue to deception was more pronounced when the interview contained probes. Lie-catchers (N=192) obtained an accuracy rate higher than chance (61.5%) for detecting deceptive denials. Implications for further research on verbal cues to deception are discussed.