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.     

Hearsay Versus Children's Testimony: Effects of Truthful and Deceptive Statements on Jurors’ Decisions

Researchers and courts are focusing increasing attention on the reliability of children's out-of-court statements, especially in relation to trials of child sexual abuse. The main goal of this study was to investigate the effects of presentation of children's out-of-court statements (e.g., hearsay) on jurors' perceptions of witness credibility and defendant guilt, and on jurors' abilities to reach the truth. Child participants experienced either a mock crime or were coached to say they experienced the crime when in fact they had not. During elaborate mock trials involving community member jurors, children's testimony was presented either: (1) live, (2) on videotape, or (3) via a social worker. Analyses revealed that testimony format directly influenced jurors' perceptions of child and social worker credibility (e.g., children were perceived as less likely to provide false statements if they testified live) as well as jurors' sympathy toward the child, all of which then predicted jurors' confidence in defendant guilt. Jurors had difficulty discerning accurate from deceptive child statements regardless of testimony format. Implications for psychology and the legal system are discussed.     

Will the Truth Come Out? The Effect of Deception,Age, Status,Coaching, and Social Skills on CBCA Scores

The impact of Veracity, Age, Status (witness or suspect), Coaching (informed or uninformed regarding CBCA), and Social Skills (social anxiety, social adroitness, and self-monitoring) on Criteria-Based Content Analysis scores was examined. Participants (aged 5–6, 10–11, 14–15, and undergraduates) participated in a rubbing the blackboard event. In a subsequent interview they told the truth or lied about the event. They were accused of having rubbed the blackboard themselves (suspect condition) or were thought to have witnessed the event (witness condition), and were or were not taught some CBCA criteria prior to the interview. CBCA scores discriminated between liars and truth tellers in children, adults, witnesses, and suspects. However, truth tellers obtained higher CBCA scores than liars only when the liars were uninformed about CBCA. CBCA scores were correlated with social skills. It is argued that these findings should caution those who believe that the validity of CBCA has been conclusively demonstrated.     

“He's guilty!”: Investigator Bias in Judgments of Truth and Deception

Detecting deception is an inherently difficult task, but one that plays a critical role for law enforcement investigators in the interrogation room. In general, research has failed to indicate that performance in this domain is improved by training or prior experience. A signal detection framework is applied to the paradigm to better conceptualize the influence of these two factors. We found that although neither factor influenced discrimination accuracy, there was an effect on response bias such that training and prior experience appeared to increase the likelihood of responding deceit as opposed to truth. This investigator bias was observed both in a review of the literature and in this study of North American law enforcement investigators who took part in a forensically based deception-detection task. Possible theoretical mechanisms and practical implications of these findings are discussed.     

Evaluation of the NITV CVSA

The purpose of this study was to evaluate a commonly used voice stress analyzer, the National Institute of Truth Verification's (NITV) Computer Voice Stress Analyzer (CVSA), using a speech database containing materials recorded (i) in the laboratory, while highly controlled deceptive and shock-induced stress levels were systematically varied, and (ii) during a field procedure. Subjects were 24 each males/females (age range 18-63 years) drawn from a representative population. All held strong views on an issue and were required to make sharply derogatory statements about it. The CVSA system was then evaluated in a double-blind study using three sets of examiners: (i) two UF scientists trained/certified by NITV in CVSA operation, (ii) three experienced NITV operators provided by the manufacturer and (iii) five experimental phoneticians. The results showed that the "true positive" (or hit) rates for all examiners ranged from chance to somewhat higher levels (c. 50-65%) for all conditions and types of materials (e.g., stress vs. unstressed, truth vs. deception). However, the false-positive rate was just as high - often higher. Sensitivity statistics demonstrated that the CVSA system operated at about chance level.     

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.     

Stress and Deception in Speech: Evaluating Layered Voice Analysis*

Abstract: This study was designed to evaluate commonly used voice stress analyzers—in this case the layered voice analysis (LVA) system. The research protocol involved the use of a speech database containing materials recorded while highly controlled deception and stress levels were systematically varied. Subjects were 24 each males/females (age range 18–63 years) drawn from a diverse population. All held strong views about some issue; they were required to make intense contradictory statements while believing that they would be heard/seen by peers. The LVA system was then evaluated by means of a double blind study using two types of examiners: a pair of scientists trained and certified by the manufacturer in the proper use of the system and two highly experienced LVA instructors provided by this same firm. The results showed that the “true positive” (or hit) rates for all examiners averaged near chance (42–56%) for all conditions, types of materials (e.g., stress vs. unstressed, truth vs. deception), and examiners (scientists vs. manufacturers). Most importantly, the false positive rate was very high, ranging from 40% to 65%. Sensitivity statistics confirmed that the LVA system operated at about chance levels in the detection of truth, deception, and the presence of high and low vocal stress states.     

Are reality monitoring differences between truthful and deceptive autobiographical accounts affected by standardisation for word-count and the presence of others?

Although a number of methods have been proposed to control for word-count differences between truthful and deceptive accounts, there is no uniformity amongst researchers using the Reality Monitoring (RM) criteria as to when, why or how to standardise for word-count differences. Another factor that also has received little attention in the literature is whether the number of others present when a person is providing an account alters the lexical profile of accounts such that RM scores are affected. To investigate these issues, 62 autobiographical statements, 31 truthful and 31 deceptive, were generated under 3 conditions, no person present, 1 and 2 persons present, and were analysed before and after standardisation for word-count and duration. Results showed that the criteria successfully discriminated between truthful and deceptive accounts when no attempt to control for word-count was made and, to a lesser extent, when accounts were standardised for duration; however, they failed to discriminate after accounts had been standardised for length. The presence of others did not affect the ability to distinguish between truthful and deceptive accounts. The results highlight the difficulties involved in developing normative standardisation criteria which could be used in the field to classify individual or small numbers of cases.