Category Archives: Police interviewing

Lie-detection biases among male police interrogators, prisoners, and laypersons

I know, I’ve been away a long time, finishing off my doctorate and working hard, so no time for blogging. The doctorate is finally out of the way but I still don’t have masses of spare time. When I can I’ll update these blogs with studies that catch my eye, though I don’t think I’ll be able to comment in depth on many of them in the way that I used to. That’s partly a time issue, but also I haven’t got access to as many full text articles as I did when I was registered at a university. I’ll do what I can.

Here’s a study that sounds like an interesting addition to the literature on what people think of their own lie-detection abilities:

Beliefs of 28 male police interrogators, 30 male prisoners, and 30 male laypersons about their skill in detecting lies and truths told by others, and in telling lies and truths convincingly themselves, were compared. As predicted, police interrogators overestimated their lie-detection skills. In fact, they were affected by stereotypical beliefs about verbal and nonverbal cues to deception. Prisoners were similarly affected by stereotypical misconceptions about deceptive behaviors but were able to identify that lying is related to pupil dilation. They assessed their lie-detection skill as similar to that of laypersons, but less than that of police interrogators. In contrast to interrogators, prisoners tended to rate lower their lie-telling skill than did the other groups. Results were explained in terms of anchoring and self-assessment bias. Practical aspects of the results for criminal interrogation were discussed.

The full text is behind a paywall – I can’t find a direct link so you have to get there by going to the publisher’s website and searching their e-journals.

New research: Outsmarting the Liars: The Benefit of Asking Unanticipated Questions

In press in the journal Law and Human Behavior, Aldert Vrij and colleagues test a method of questioning that (in lab situations) exposes liars with an up to 80% success rate. Here’s the abstract:

We hypothesised that the responses of pairs of liars would correspond less with each other than would responses of pairs of truth tellers, but only when the responses are given to unanticipated questions. Liars and truth tellers were interviewed individually about having had lunch together in a restaurant. The interviewer asked typical opening questions which we expected the liars to anticipate, followed by questions about spatial and/or temporal information which we expected suspects not to anticipate, and also a request to draw the layout of the restaurant. The results supported the hypothesis, and based on correspondence in responses to the unanticipated questions, up to 80% of liars and truth tellers could be correctly classified, particularly when assessing drawings.

Reference:

At the moment you can download the article for free here (pdf).

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

Continuing with their research on the ‘cognitive load hypothesis’, Aldert Vrij and colleagues from Portsmouth University report on a technique for facilitating lie detection – telling the story in reverse order. This article appears in the latest issue of Law and Human Behavior, although the study featured extensively in the press a few months ago (see here ).

Here’s the abstract:

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.

Reference:

Cues to Deception and Ability to Detect Lies as a Function of Police Interview Styles

interrogateIf you were a police officer, what sort of interview style would offer you the best chance of detecting whether or not your interviewee was telling lies? Aldert Vrij and his colleagues ran a study to find out:

In Experiment 1, we examined whether three interview styles used by the police, accusatory, information-gathering and behaviour analysis, reveal verbal cues to deceit, measured with the Criteria-Based Content Analysis (CBCA) and Reality Monitoring (RM) methods. A total of 120 mock suspects told the truth or lied about a staged event and were interviewed by a police officer employing one of these three interview styles. The results showed that accusatory interviews, which typically result in suspects making short denials, contained the fewest verbal cues to deceit. Moreover, RM distinguished between truth tellers and liars better than CBCA. Finally, manual RM coding resulted in more verbal cues to deception than automatic coding of the RM criteria utilising the Linguistic Inquiry and Word Count (LIWC) software programme.

In Experiment 2, we examined the effects of the three police interview styles on the ability to detect deception. Sixty-eight police officers watched some of the videotaped interviews of Experiment 1 and made veracity and confidence judgements. Accuracy scores did not differ between the three interview styles; however, watching accusatory interviews resulted in more false accusations (accusing truth tellers of lying) than watching information-gathering interviews. Furthermore, only in accusatory interviews, judgements of mendacity were associated with higher confidence. We discuss the possible danger of conducting accusatory interviews.

In the discussion, Vrij and colleagues summarise:

The present experiment revealed that style of interviewing did not affect on overall accuracy (ability to distinguish between truths or lies) or on lie detection accuracy (ability to correctly identify liars). In fact, the overall accuracy rates were low and did not differ from the level of chance. This study, like so many previous studies (Vrij, 2000), thus shows the difficulty police officers face when discerning truths from lies by observing the suspect’s verbal and nonverbal behaviours.

In other words, if law enforcement officers want to increase their chances of detecting deception, they need to make sure interviewers use an information gathering approach. But simply watching that interview (live or on tape) might not help them decide whether or not the suspect is telling the truth – they may need to subject a transcript to linguistic analysis to give themselves the best chance.

Even if it doesn’t result in better ‘live’ judgements of veracity, an information gathering approach has another advantage for the law enforcement officer: it maximises the number of checkable facts elicited from the suspect, and being able to check a fact against the truth is pretty much the most effective means of uncovering false information. Of course, someone can provide false information without deliberately lying: if they have misremembered something, for instance, or are passing on something that someone else lied to them about. But then the point of any law enforcement interview is to get to the truth, which is a higher goal than simply uncovering a liar, in my opinion.

As always with lab-based studies, there are some limitations. Vrij et al., for instance, acknowledge that “in practice elements of all three styles may well be incorporated in one interview” but explain that “we distinguished between the three styles in our experiments because we can only draw conclusions about the effects of such styles only by examining them in their purest form”.

Further problems, which are difficult to overcome in structured lab settings, are caused because participants were assigned randomly to ‘guilty’ (liars) or ‘innocent’ (truth tellers) conditions. In the real world, individuals who are prepared put themselves in a situation in which they might later have to lie may differ in their ability to lie effectively than those who try to stay out of such situations. And real guilty suspects make a decision about whether they are going to lie (a few confess from the start, others will offer partial or whole untruths). It’s an issue that is open to empirical test: let participants choose whether they want to be in the ‘guilty’ or ‘innocent’ conditions (or have four conditions: guilty choice/guilty no choice/innocent choice/innocent no choice).

Also, in this study the liars were told what lie to tell (as opposed to being able to make one up). Real guilty suspects who decide to lie will presumably choose a lie that they they think they stand a good chance of being able to get away with. In real world conditions, the perception by the guilty individual of what sort of situation they’re in, the evidence against them, the plausible story they can tell to explain away the evidence, and their ability to lie effectively are probably all important.

Reference:

Photo credit: scottog, Creative Commons License

New interview technique could help police spot deception

liar… according to a press release from the Economic and Social Research Council (7 June):

Shifting uncomfortably in your seat? Stumbling over your words? Can’t hold your questioner’s gaze? Police interviewing strategies place great emphasis on such visual and speech-related cues, although new research funded by the Economic and Social Research Council and undertaken by academics at the University of Portsmouth casts doubt on their effectiveness. However, the discovery that placing additional mental stress on interviewees could help police identify deception has attracted interest from investigators in the UK and abroad.

[...] A series of experiments involving over 250 student ‘interviewees’ and 290 police officers, the study saw interviewees either lie or tell the truth about staged events. Police officers were then asked to tell the liars from the truth tellers using the recommended strategies. Those paying attention to visual cues proved significantly worse at distinguishing liars from those telling the truth than those looking for speech-related cues.

[...] However, the picture changed when researchers raised the ‘cognitive load’ on interviewees by asking them to tell their stories in reverse order. Professor Aldert Vrij explained: “Lying takes a lot of mental effort in some situations, and we wanted to test the idea that introducing an extra demand would induce additional cues in liars. Analysis showed significantly more non-verbal cues occurring in the stories told in this way and, tellingly, police officers shown the interviews were better able to discriminate between truthful and false accounts.”

Asking an interviewee to tell their story in reverse order is not a new interview technique – it’s one of the techniques used in the Cognitive Interview, more usually deployed to get maximum detail in statements from victims and witnesses.

There are also detailed articles in the UK Times and Daily Telegraph newspapers based on (and building on) this press release.

More details, and links to downloadable reports, are available on the ESRC website via this link.

References:

Photo credit: Bingo_little, Creative Commons License

Truth serums and “brain fingerprinting” used in Indian serial killer case

A serial killing case in India has caused quite a stir in recent weeks, with suspicions that the murders are linked to human organ trafficking operations and allegations of police incompetence in investigating the disappearances of the children. The Observer (UK, 7 Jan) explains:

Forty or more people, ranging from a boy aged 10 months to a 32-year-old mother of three, may have fallen victim to two of India’s most prolific serial killers as the authorities revealed their suspicion that murders may have been carried out to harvest body parts such as kidneys, livers and kneecaps.

[...] Yesterday, as police fought to control further riots by angry locals, the leader of India’s ruling coalition, Sonia Gandhi, made a surprise visit to the scene of the crime and harshly criticised the local police handling of the investigation. Responsibility for it has now been handed over to India’s top federal investigating agency, the Central Bureau of Investigation.

In the last week, six police officers have been suspended after it emerged that Pandher, the prime suspect in the case, was arrested 13 months ago following a series of complaints from local residents in the slum bordering his house who suspected his involvement in the disappearance of their children. But the suspect walked out of the police station the same night.

Two men have been arrested in the case, and CNN-IBN News (5 Jan) explains what lies in store:

The Forensic Science Laboratory (FSL) in Gandhinagar, Gujarat, is currently conducting a narco-analysis test on the two accused in the Nithari serial killings case – Moninder Singh Pandher and Surinder.

[...] An anesthetist, a forensic expert and two psychologists. All of them are being given a comprehensive briefing by the Noida Police as to the questions that need to be posed to the accused once the truth serum has been administered.

[...] Assistant Director, FSL, Gandhinagar, V H Patel, “We inject drugs into a person, which makes his conscious mind relax. It is under the influence of these drugs that a person begins to speak out the things that he would normally try to hide.”

The chemical injected during the test is sodium pentathol, which is popularly known as the truth serum, for obvious reasons. [...] The effect of the drug makes the person semi conscious, restricting their ability to manipulate answers or use their imagination.

In addition to the narco-analysis test, the Nithari accused will have to undergo a Brain Finger Printing Test and a Lie Detection or Polygraph Test.

[...] Says an FSL official, Namrata Khopkar, “Once the sensors are placed, and we show pictures to the accused and make them hear things. The way one’s brain reacts to these sounds can establish a lot of things.”

Both the use of sodium pentathol and “brain fingerprinting” techniques are highly controversial. Previous Deception Blog posts on ‘truth serums’ can be found here, and previous coverage of the use of brain scans by the Indian police can be found here and here.

When training to detect deception works

In the October 2006 issue of Law and Human Behavior (vol 30, issue 5), Maria Hartwig and her colleagues present research on training law enforcement officers to detect deception:

Research on deception detection in legal contexts has neglected the question of how the use of evidence can affect deception detection accuracy. In this study, police trainees (N=82) either were or were not trained in strategically using the evidence when interviewing lying or truth telling mock suspects (N=82). The trainees’ strategies as well as liars’ and truth tellers’ counter-strategies were analyzed. Trained interviewers applied different strategies than did untrained. As a consequence of this, liars interviewed by trained interviewers were more inconsistent with the evidence compared to liars interviewed by untrained interviewers. Trained interviewers created and utilized the statement-evidence consistency cue, and obtained a considerably higher deception detection accuracy rate (85.4%) than untrained interviewers (56.1%).

Check out that accuracy rate – 85%!

Reference:

US police officers’ knowledge regarding behaviors indicative of deception

Lori Colwell and colleagues from Sam Houston State University have published in the latest issue of Psychology Crime and Law:

The current study surveyed a random sample of Texas law enforcement officers (n=109) about their knowledge regarding behaviors indicative of deception. The officers were not highly knowledgeable about this topic, overall performing at a chance level in assessing how various behavioral cues relate to deception. Confidence in one’s skill was unrelated to accuracy, and officers who reported receiving the most training and utilizing these skills more often were more confident but no more accurate in their knowledge of the behaviors that typically betray deception. The authors compare these results to previous studies that have examined officers’ beliefs in other countries and discuss the implication of these results in terms of developing future training programs that may debunk the common misconceptions that officers possess.

Lori H. Colwell, Holly A. Miller, Rowland S. Miller, Phillip M. Lyons, Jr. (2006). US police officers’ knowledge regarding behaviors indicative of deception: Implications for eradicating erroneous beliefs through training. Psychology, Crime and Law 12(5): 489-503

See also:

  • Training law enforcement officers to detect deception which reported on the same study, presented differently (Lori H. Colwell, Holly A. Miller, Phillip M. Lyons, Jr., Rowland S. Miller (2006). The Training of Law Enforcement Officers in Detecting Deception: A Survey of Current Practices and Suggestions for Improving Accuracy. Police Quarterly 9(3): pp 275-290)

Police officers ability to detect deception in high stakes situations

There’s another study from Aldert Vrij and his colleagues at Portsmouth University in the latest issue of Applied Cognitive Psychology. The rationale for the study is interesting and relevant to anyone who is interested in real-life deception detection. In previous studies, participants have tended to be shown just one (or one set) of clips on one occasion. Conclusions are drawn about individual differences on the basis of such tests, but Vrij and his colleagues wondered how meaningful these conclusions actually are. After all:

The problem is that participants are typically tested only once. It therefore cannot be ruled out that a particular good or bad performance on the single lie detection task was just a matter of luck. This is a particularly relevant point in studies where attempts are made to unravel the strategies used by good lie detectors.

The materials were clips from real suspect interviews where ground truth was known (and the stakes were high), and the participants were real, experienced police officers (average 6.9 years in police service). A welcome step forward from the usual students / students studies, and well done to the UK police force concerned for facilitating the research. The officers’ task was to judge four sets of clips of liars / truth tellers on four different occasions. The results:

1. The total accuracy (four tests combined) was 72%. This is an improvement on the usual 50-60% hit rate typically found in lab studies of deception detection (DePaulo et al., 2003).

2. Vrij and colleagues “did not find consistency in officers’ performance over the four tests, suggesting that performance on individual tests is, as we predicted, partly caused by luck”.

3. They found that officers were equally good at detecting truth (70% accuracy) and lies (73%).

4. They found that “officers were overly modest about, rather than overconfident in, their performance”. On average officers tended to believe (both before and after the tests) that they had only performed at chance level.

Neat.

Training law enforcement officers to detect deception

A good overview of literature on deception detection training, and some sensible suggestions for improving training in this article from the latest issue of Police Quarterly.

Abstract:

The current study surveyed a random sample of Texas law enforcement officers (N = 109) about their training in detecting deception. Texas officers reported that their training entailed the equivalent of a 2-day, lecture-style workshop in the kinesic interview technique or Reid technique, two popular police training modules, with subsequent training more often the exception than the rule. The authors examine these results in light of previous social science research regarding officers’ accuracy in detecting deception and make suggestions for future training programs for police officers in this area.

Recommendations for training include:

  • Draw on the research literature (“In general, training appeared to neglect any discussion of social science research findings…” [p285])
  • Address myths about deception detection (current courses apparently focus on cues but not erroneous beliefs)
  • Give students plenty of practice with statements and video clips (currently lectures seem to predominate)
  • Give consistent and timely feedback on accuracy
  • Spend time on credibility assessment for victims and witnesses (current courses seem almost exclusively focused on suspect interviewing)

Reference:

Confounding influences on police detection of suspiciousness

Published online last week, this article by Richard Johnson (Washburn University, KS, USA) in the Journal of Criminal Justice reports a study of how police officers make decisions about ‘suspiciousness’, in particular looking at how US officers interacted with Caucasian, Hispanic and African American members of the public. Here’s the abstract:

The social psychological literature had shown wide acceptance by the police of the use of nonverbal behaviors such as smiles, speech disruptions, gaze aversion, and hand gestures as cues to deceptive or suspicious activity by criminal suspects. Current police investigative training also reinforces these beliefs. The present study analyzed the influence of race and emotional agitation level on the frequency with which these ‘suspicious’ nonverbal behaviors are displayed. Reviewing 120 videotaped police-citizen interactions of a noncriminal nature involving law-abiding citizens, the results suggested that level of emotional agitation had a weak but significant influence on the frequency with which two of these nonverbal behaviors were displayed. Race also had a significant influence that ranged from moderate to strong, as African-American and Hispanic citizens displayed significantly higher levels than Caucasians of behaviors thought of as ‘suspicious’ by police officers.

If you have a subscription to Journal of Criminal Justice you can read the article in press via the Science Direct pages for the journal.

Testing the Behavior Analysis Interview

The Reid Technique of Interviewing and Interrogation is probably the most widely known interrogation technique – or, to be accurate, collection of techniques – and is used by thousands of law enforcement officers throughout the USA and beyond (though not in the UK). However, the method is controversial: many claim that the potentially coercive nature of the questioning may prompt false confessions by innocent but suggestible interviewees (see, for example, the work of Saul Kassin, Gisli Gudjonsson, Richard Leo and Richard Ofshe).

The latest issue of Law and Human Behavior 30(3) includes an article by Aldert Vrij, Samantha Mann and Ronald Fisher, who present the results of their study to test the Reid Technique’s Behaviour Analysis Interview. According to the Reid Institute website:

The BAI consists of a series of investigative questions that are specifically developed for each case, and a series of behavior provoking questions that elicit verbal and nonverbal responses which serve to help identify those persons who should be eliminated from suspicion, and those who are most likely involved in committing the act under investigation. During the BAI the subject is also asked a series of questions to determine whether or not they have the propensity to commit the act in question.

Vrij and his colleagues set out to test whether the BAI did indeed provoke responses that reliably differentiate liars from truth-tellers. Read on to find out what they found.
Continue reading

Call me picky, but Brain Fingerprinting and fMRI are not the same thing…

The All About Forensic Psychology Blog (28 May) picked up on an article by Robert Ellman (Intrepid Liberal Journal) in Political Cortex about the implications of brain scanning for lie detection in forensic settings. AAFP author David Webb writes:

Fascinating article adressing the potential use and implications of Functional Magnetic Resonance Imaging (FMRI) i.e. brain fingerprinting. [...] Given the concerns regarding the documented unreliability of the polygraph (lie detector), Silberman contends that subject to further empircial testing, Functional Magnetic Resonance Imaging (FMRI) may prove effective in solving crimes or preventing terrorism.

I’m enjoying the AAFP Blog a lot: David often finds interesting FP articles that I wouldn’t otherwise come across. But, at the risk of being picky, I need to correct a few things David’s post about brain scanning. To be fair, his post reflects confusion in the original article about the differences between brain fingerprinting, brain scanning and fMRI. They are not the same thing. Let’s try and sort this out, without getting too technical:

Brain scanning is a generic term used in many different contexts by many different authors usually to refer to any technique that measures brain activity.

Brain Fingerprinting is the name given by Lawrence Farwell to a technique for detecting guilty knowledge using EEG. EEGs measure electrical activity across a subject’s brain (electrical signals known as Event Related Potentials or ERPs) when the subject is exposed to a stimulus. Farwell claims that Brain Fingerprinting can detect whether a stimulus is novel or familiar to the subject.

fMRI is a technique for measuring brain activity by measuring changes in the concentration of oxygenated haemoglobin in the brain. In deception detection, using fMRI can, researchers suggest, detect changes in the pattern of subjects’ brain activity when lying compared to when they are telling the truth.

None of these techniques consitutes a ‘lie detector’. Nor is the polygraph (sorry, David, I’m being picky again). The techniques simply measure changes in physiology or brain activity in response to a stimulus. The decision as to whether that change is a result of deception depends on the stimulus that caused the change (e.g. the question being asked, or, perhaps, the photo being shown) and how that change is interpreted.

For anyone new to this area – or even with a bit of knowledge of the field – I’d recommend a great article that appeared in the American Journal of Bioethics last year on the promises and perils of lie detection. The paper, by Paul Root Wolpe, Kenneth R Foster and Daniel L Langleben (all at the University of Pennsylvania) does a terrific job of setting out clearly some of the problems in deploying Emerging Neurotechnologies for Lie Detection and is also a good source for summaries of the theoretical, ethical and practical issues involved in deploying EEG measurements and fMRI for deception detection.

As far as the authors know, Farwell’s Brain Fingerprinting is the only one of the new neurotechnologies that has been used in real-life forensic settings and only once (according to Wolpe et al.) has it been used in court in the US. As Wolpe et al explain, in Harrington vs Iowa (a 2003 post-conviction relief hearing), Farwell submitted Brain Fingerprinting evidence that Harrington had no knowledge of the crime scene. Harrington was freed, but Wolpe et al. contend that the Brain Fingerprinting evidence was essentially irrelevant to the court’s decision. They add,

as the State of Iowa complained in its brief against Brain Fingerprinting in Harrington, the most critical problem with admission of Brain Fingerprinting evidence is the lack of any track record establishing its reliability (p47).

Despite this, it appears that the Indian Police is using Brain Fingerprinting in real-life cases, where suspects’ liberty is at stake. This blog – and OmniBrain and Neurofuture – mentioned these concerns before and Robert Ellman picks up on more evidence that this untested technology is being used by the Indian Police. He provides links to articles in New Kerala newspaper highlighting how Brain Fingerprinting (not fMRI, as Ellman suggests) is being used, for instance:

The court had earlier awarded life imprisonment to Javed and six others [...] for rioting and murdering a man on November 11, 2003 [...] The judge awarded the sentence after considering the results of the brain fingerprinting tests performed on the accused, among other facts in this case.

Ellman also highlights concerns that ‘cognitive profiling’ might one day be applied to

[...] search suspects for brain waves that suggest a propensity toward violence — a sort of cognitive profiling. ‘You can do an FMRI scan showing that the structures in the brain responsible for impulse control and empathy are underactive and the parts of the brain responsible for aggression and more animalistic, violent activities are overactive,’ Snead explained. ‘Maybe with these nascent technologies, we’ll be able to develop some kind of profile for a terrorist.’ Suspects who show a propensity for violence might be detained indefinitely as enemy combatants even though they committed no crimes.

Minority Report here we come.

Reference:

UPDATE (16 June):

Sandra helpfully points out in the comments below that the ‘Brain Fingerprinting’ being used in India is not the same as the BF developed by Lawrence Farwell, though it seems to be based on the same principle.

    ABC Primetime report on false confessions and interview tactics

    ABC Primetime last Thursday (30 Mar) screened a special report on false confessions and police interview tactics. The report featured a great interview with “Dr” Charles Humble, millionaire CEO of the National Institute for Truth Verification, the company that markets the tremendously successful Computer Voice Stress Analyzer. Humble claims that the system has a 98% accuracy rate in the field, but admits in interview that there are no independent scientific studies to validate this claim, is put under pressure on suggestions that the CVSA might have contributed to false confessions and is questioned about his title of ‘Dr’ which appears to add credibility to his claims to be marketing a scientific system. Humble eventually admits that his doctorate was granted by an Indiana Bible college after Humble took six hours of Bible classes.

    You can view segments of the programme (including the Humble interview) here.

    UPDATE: Not any more.  However, the story can still be accessed here.

    Behavioral Cues to Deception vs. Topic Incriminating Potential in Criminal Confessions

    Martha Davis, Keith A. Markus, Stan B. Walters, Neal Vorus and Brenda Connors
    Law and Human Behavior 29(6), pp 683 – 704, December 2005

    Coding statements of criminal suspects facilitated tests of four hypotheses about differences between behavioral cues to deception and the incriminating potential (IP) of the topic. Information from criminal investigations corroborated the veracity of 337 brief utterances from 28 videotaped confessions. A four-point rating of topic IP measured the degree of potential threat per utterance. Cues discriminating true vs. false comprised word/phrase repeats, speech disfluency spikes, nonverbal overdone, and protracted headshaking. Non-lexical sounds discriminated true vs. false inthe reverse direction. Cues that distinguished IP only comprised speech speed, gesticulation amount, nonverbal animation level, soft weak vocal and “I (or we) just” qualifier. Adding “I don’t know” to an answer discriminated both IP and true vs. false. The results supported hypothesis about differentiating deception cues from incriminating potential cues in high-stakes interviews, and suggested that extensive research on distinctions between stress-related cues and cues to deception would improve deception detection.

    Detecting Deception Via Strategic Disclosure of Evidence

    Maria Hartwig, Pär Anders Granhag, Leif A. Strömwall and Aldert Vrij
    Law and Human Behavior 29(4), pp 469-484, August 2005

    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.