Category Archives: Polygraph

Quick deception links for the last few weeks

Gah, Twitter update widget broken. Here are the deception-relevant tweets from the last few weeks:

Polygraph and similar:

  • Detecting concealed information w/ reaction times: Validity & comparison w/ polygraph App Cog Psych 24(7)
  • Important (rare) study on polygraph w/ UK sex offenders: leads to more admissions; case mgrs perceive increased risk

fMRI and other brain scanning:

  • If Brain Scans Really Detected Deception, Who Would Volunteer to be Scanned? J Forensic Sci
  • FMRI & deception: “The production and detection of deception in an interactive game” in Neuropsychologia
  • In the free access PLoS1: fMRI study indicates neural activity associated with deception is valence-related. PLoS One 5(8).

Verbal cues:

  • Distinguishing truthful from invented accounts using reality monitoring criteria –
  • Detecting Deceptive Discussions in Conference Calls. Linguistic analysis method 50-65% accuracy. SSRN via
  • Effect of suspicion & liars’ strategies on reality monitoring Gnisci, Caso & Vrij in App Cog Psy 24:762–773

Applied contexts:

  • A new Canadian study on why sex offenders confess during police interrogation (no polygraph necessary)
  • Can fabricated evidence induce false eyewitness testimony? App Cog Psych 24(7) Free access
  • In press, B J Soc Psy Cues to deception in context. Apparently ‘context’ = ‘Jeremy Kyle Show’. Can’t wait for the paper!
  • Can people successfully feign high levels of interrogative suggestibility & compliance when given instructions to malinger?

Kids fibbing:

  • Eliciting cues to children’s deception via strategic disclosure of evidence App Cog Psych 24(7)
  • Perceptions about memory reliability and honesty for children of 3 to 18 years old –

And some other links of interest:

Research Round-up 5: Polygraphy

Part 5 in the rapid research round-up for 2008 includes some of the articles to appear over the last year relating to physiological detection of deception.

The first paper here is the most interesting to me, particularly because there are rather few published research findings relating to what happens when people are polygraphed in their non-native language, but the others are probably only really of interest to hard-core psychophysiologists. If these all seem pretty heavy then I’d recommend heading over to a delightful post about William Moulton Marsden, one of the early pioneers of the polygraph, written by Romeo Vitelli at the Providentia blog, for some light relief.

Bilingual speakers frequently report experiencing greater emotional resonance in their first language compared to their second. In Experiment 1, Turkish university students who had learned English as a foreign language had reduced skin conductance responses (SCRs) when listening to emotional phrases in English compared to Turkish, an effect which was most pronounced for childhood reprimands. A second type of emotional language, reading out loud true and false statements, was studied in Experiment 2… Results suggest that two factors influence the electrodermal activity elicited when bilingual speakers lie in their two languages: arousal due to emotions associated with lying, and arousal due to anxiety about managing speech production in non-native language. Anxiety and emotionality when speaking a non-naive language need to be better understood to inform practices ranging from bilingual psychotherapy to police interrogation of suspects and witnesses.

The effects of the state of guilt and the context in which critical information was received on the accuracy of the Concealed Information Test (CIT) were examined in a between-subjects mock crime experiment… Results indicated that accomplices were more effectively detected than innocent participants, although both were given the same critical information. Information gathered in the crime context yielded stronger orientation to the critical items than similar information gathered in a neutral context.

The present mock-crime study concentrated on the validity of the Guilty Actions Test (GAT) and the role of the orienting response (OR) for differential autonomic responding. N = 105 female subjects were assigned to one of three groups: a guilty group, members of which committed a mock-theft; an innocent-aware group, members of which witnessed the theft; and an innocent-unaware group… For informed participants (guilty and innocent-aware), relevant items were accompanied by larger skin conductance responses and heart rate decelerations whereas irrelevant items elicited HR accelerations. Uninformed participants showed a non-systematic response pattern.

Following the idea that response inhibition processes play a central role in concealing information, the present study investigated the influence of a Go/No-go task as an interfering mental activity, performed parallel to the Concealed Information Test (CIT), on the detectability of concealed information… No physiological evidence for an interaction between the parallel task and sub-processes of deception (e.g. inhibition) was found. Subjects’ performance in the Go/No-go parallel task did not contribute to the detection of concealed information.

The Concealed Information Test (CIT) requires the examinee to deceptively deny recognition of known stimuli and to truthfully deny recognition of unknown stimuli. Because deception and orienting are typically coupled, it is unclear how exactly these sub-processes affect the physiological responses measured in the CIT…The present study aimed at separating the effects of deception from those of orienting…The findings further support the notion that psychophysiological measures elicited by a modified CIT may reflect different mental processes involved in orienting and deception.

The final part of this research round-up includes papers on children’s deception, and on technotreachery.

Deception in the news

I’ve been lax posting on the blogs recently, I know (real life interferes with blogging). Consider this a catch-up post with some of the deception-related issues hitting the news stands over the last few weeks.

Polygraphing sex offenders gains momentum in the UK: A new pilot scheme to polygraph test sex offenders to see if they “are a risk to the public or are breaking the terms of their release from jail”, according to The Times (20 Sept 2008).

Brain fingerprinting in the news again: Brain test could be next polygraph (Seattle Post-Intelligencer, 14 Sept):

A Seattle scientist who has developed an electronic brain test that he says could improve our ability to force criminals to reveal themselves, identify potential terrorists and free those wrongly convicted may have finally broken through the bureaucratic barriers that he believes have served to stifle adoption of the pioneering technique.

“There seems to be a renewed surge of interest in this by the intelligence agencies and the military,” said Larry Farwell, neuroscientist and founder of Brain Fingerprinting Laboratories based at the Seattle Science Foundation.

Not-brain-fingerprinting deception detection brain scan procedure isn’t scientific, according to a well-qualified panel (The Hindu, 8 Sept). India’s Directorate of Forensic Sciences chooses not to accept the panel’s findings:

The Directorate of Forensic Sciences, which comes under the Union Ministry of Home, will not accept the findings of the six-member expert committee that looked into brain mapping and its variant “brain electrical oscillation signature (BEOS) profiling” on the ground that the committee has been dissolved.

The six-member technical peer review committee, headed by National Institute of Mental Health and Neuro Sciences (NIMHANS) Director D. Nagaraja, started work in May 2007. The panel had concluded that the two procedures were unscientific and had recommended against their use as evidence in court or as an investigative tool.

  • See also: more on “BEOS profiling” in The Times of India (21 July) which claims that “This brain test maps the truth”.

Perhaps the answer can be found with infrared light? New Scientist (22 Sept) reports on a patent application to develop a new type of brain scanning lie detection technology:

Scott Bunce, at Drexel University’s College of Medicine in Philadelphia, thinks a better solution [to the problem of detecting lies] is to send near-infrared light through the scalp and skull into the brain and see how much is reflected back. And he has designed a special headband that does just that. The amount of reflected light is dependent on the levels of oxygen in the blood, which in turn depends on how active the brain is at that point.

This, he says, gives a detailed picture of real-time activity within the brain that can be used to determine whether the subject is lying. The technique is both cheaper and easier to apply than fMRI and gives a higher resolution than an EEG. …Of course, nobody knows whether brain activity can reliably be decoded to reveal deception, but that’s another question.

Polygraph reasoning applied to spotting terrorists…

Remember that the rationale behind the polygraph is that (with an appropriate questioning regime) guilty people are assumed have physiological responses that differ from innocents? Well, the new “anxiety-detecting machines” that the DHS hopes might one day spot terrorists seem to work on the same basis. Here’s the report from USA Today (18 Sept):

A scene from the airport of the future: A man’s pulse races as he walks through a checkpoint. His quickened heart rate and heavier breathing set off an alarm. A machine senses his skin temperature jumping. Screeners move in to question him. Signs of a terrorist? Or simply a passenger nervous about a cross-country flight?

It may seem Orwellian, but on Thursday, the Homeland Security Department showed off an early version of physiological screeners that could spot terrorists. The department’s research division is years from using the machines in an airport or an office building— if they even work at all. But officials believe the idea could transform security by doing a bio scan to spot dangerous people.

Critics doubt such a system can work. The idea, they say, subjects innocent travelers to the intrusion of a medical exam.

According to the news report, there is some effort going into testing the equipment, though if the details in the news report are to be believed it sounds like the research is still at a very early stage:

To pinpoint the physiological reactions that indicate hostile intent, researchers… recruited 140 local people with newspaper and Internet ads seeking testers in a “security study.” Each person receives $150.

On Thursday, subjects walked one by one into a trailer with a makeshift checkpoint. A heat camera measured skin temperature. A motion camera watched for tiny skin movements to measure heart and breathing rates. As a screener questioned each tester, five observers in another trailer looked for sharp jumps on the computerized bands that display the person’s physiological characteristics.

Some subjects were instructed in advance to try to cause a disruption when they got past the checkpoint, and to lie about their intentions when being questioned. Those people’s physiological responses are being used to create a database of reactions that signal someone may be planning an attack. More testing is planned for the next year.

The questioning element does make it sound like what is being developed is a ‘remote’ polygraph.

Hat tip to Crim Prof Blog.

UPDATE: Lots of places picking this up all over the www. New Scientist has a post on the same topic here, and an earlier article on the system here. The Telegraph’s report adds some new information.

Deception research across the blogosphere

The physiology of lying by exaggerating: Over at the BPS Research Digest Blog, a summary of research that has caused ripples around the media: lying by exaggeration doesn’t seem to cause the typical physiological arousal effects that some associate with liars:

Telling lies about our past successes can sometimes be self-fulfilling, at least when it come to exam performance. That’s according to the New York Times, which reports on studies by Richard Gramzow at the University of Southampton and colleagues.

Their research has shown that, when asked, many students exaggerate their past exam performance, and that those students who do this tend to go on to perform better in the future.

What’s more, a study published in February showed that when these exaggerators are interviewed about their past academic performance, they don’t show any of the physiological hallmarks associated with lying, but rather their bodies stay calm. It’s almost as though this is a different kind of lying, aimed more at the self, with the hope of encouraging improved future performance.

More commentary on this research over at Deric Bownds’ Mind Blog.


Two popular articles on deception: Via the Situationist Blog (7 April), a link to an article in Forbes on “how to sniff out a liar” (which doesn’t include any hints for olfactory detection of deceivers!). And hat tip to the Antipolygraph Blog (16 April) for pointing us toThe Lie of Lie Detectors By Rob Shmerling:

Recently, two studies announced effective ways to determine whether a person was telling the truth — one used a brain scan while the other detected heat around the face. Since you probably tell the truth all of the time, it is likely that these reports will have no direct bearing on you. But, for those who perform lie detector tests or for those who might be asked to submit to one, these techniques could someday change how these tests are performed.

The Pentagon’s “Porta-Poly”: The news that the Pentagon is trialling a ‘pocket lie detector’ known as the Preliminary Credibility Assessment Screening System (PCASS) for soldiers has been picked up and commented upon by a number of sources including Bruce Schneier and the Anti-Polygraph Blog, but don’t skip the original MSN story which is well worth reading.

Update: Missed one: Over at Practical Ethics, in Fighting Absenteeism with Voice Analysis (16 May).  The news that some companies are apparently considering using this discredited technology to check up on workers calling in sick is chilling.

Quick round up of deception news

Sorry for the slow posting recently – real life is getting in the way of blogging at the moment., and is likely to continue to do so for some time yet, so please bear with me. Perhaps some of these items will give you your deception research fix in the meantime.

If you’d like something to listen to during the daily commute why not download an interview with John F. Sullivan, author of Gatekeeper: Memoirs of a CIA Polygraph Examiner (h/t Antipolygraph Blog).

Alternatively, try a short NPR Morning Edition segment on the neuropsychology of lying (h/t and see also The Frontal Cortex).

The ever-interesting BPS Research Digest discusses a study of how toddlers tell a joke from a mistake. According to the researchers, Elena Hoicka and Merideth Gattis:

…the ability to recognise humorous intent comes after the ability to recognise jokes, but before the ability to recognise pretense and lies. “We propose that humour understanding is an important step toward understanding that human actions can be intentional not just when actions are right, but even when they are wrong,” they concluded.

Karen Franklin has a terrific commentary on the Wall Street Journal’s discussion of a subscale of the MMPI, which claims to detect malingerers but which, according to critics, results in a large number of false positives (i.e., labelling truthful test-takers as malingerers). (See also a short commentary by Steven Erikson).

There are two articles by Jeremy Dean of the glorious PsyBlog on false memories (here and here).

And finally, Kai Chang at Overcoming Bias reports on an unusual teaching technique which involves asking students to spot the Lie of the Day.

Simple test improves accuracy of polygraph results

polygraphA press release from Blackwell Publishing (28 Nov) highlights a new study coming out in the next issue of the journal Psychophysiology.

In order to prevent false positive results in polygraph examinations, testing is set to err on the side of caution. This protects the innocent, but increases the chances that a guilty suspect will go unidentified. A new study published in Psychophysiology finds that the use of a written test, known as Symptom Validity Testing (SVT), in conjunction with polygraph testing may improve the accuracy of results.

SVT is an independent measure that tests an entirely different psychological mechanism than polygraph examinations. It is based on the rationale that, when presented with both real and plausible-but-unrelated crime information, innocent suspects will show a random pattern of results when asked questions about the crime. SVT has previously been shown as effective in detecting post-traumatic stress disorder, amnesia and other perceptual deficits for specific events.

The study finds that SVT is also an easy and cost-effective method for determining whether or not a suspect is concealing information. In simulated cases of mock crime questioning and feigned amnesia, it accurately detected when a participant was lying.

Furthermore, when used in combination with the preexisting but relatively uncommon concealed information polygraph test (CIT), test accuracy is found to be higher than when either technique is used alone.

“We showed that the accuracy of a Concealed Information Test can be increased by adding a simple pencil and paper test,” says lead author Ewout Meijer of Maastricht University. “When ‘guilty’ participants were forced to choose one answer for each question, a substantial proportion did not succeed in producing the random pattern that can be expected from ‘innocent’ participants.”


Abstract below the fold

Photo credit: pauldwaite, Creative Commons License

Continue reading Simple test improves accuracy of polygraph results

NPR on lie detection

Hat tip to (a great blog associated with the American Journal of Bioethics):

This past week NPR’s Morning Edition carried a three-part series about lie detection reported by Dina Temple-Raston. (The segments are posted as both audio and text, so they’re easy to scan if you can’t listen.) The series covers the questionable accuracy of polygraphs, the emerging field of lie detection by fMRI, and the examination of facial “micro expressions” for hints of lies.

Head over to for some commentary, or go straight to the NPR site for more details.

Can lie detectors be trusted?

Detailed commentary from Patrick Barkham in the Guardian (18 Sept), exploring the use of ‘lie detecting’ machines in the UK. He covers the use of voice stress analysis in benefit offices and insurance companies, and polygraphy for sex offenders. Interesting stuff, and well worth reading in full over on the Guardian site. Here’s a flavour:

[Harrow] council prefers the phrase “voice risk analysis” and Capita calls its combination of software, special scripts and training for handlers the “Advanced Validation Solution”. Just don’t say it’s a lie detector. “Please don’t call it that. We’re not happy with that. It’s an assessment,” says Fabio Esposito, Harrow’s assistant benefit manager.

… Voice stress analysis systems have been used for more than five years in the British insurance industry but have yet to really catch on, according to the Association of British Insurers. There was an initial flurry of publicity when motor insurance companies introduced the technology in 2001 but it is still “the exception rather than the norm,” says Malcolm Tarling of the ABI. “Not many companies use it and those that do use it in very controlled circumstances. They never use the results of a voice risk analysis alone because the technology is not infallible.”

… Next year, in a pilot study, the government will introduce a mandatory polygraph for convicted sex offenders in three regions. … Professor Don Grubin, a forensic psychiatrist at Newcastle University… admits he was initially sceptical but argues that polygraphs are a useful tool. “We were less concerned about accuracy per se than with the disclosures and the changes in behaviour it encourages these guys to make,” he says. “It should not be seen as a lie detector but as a truth facilitator. What you find is you get markedly increased disclosures. You don’t get the full story but you get more than you had.”

…critics argue that most kinds of lie-detector studies are lab tests, which can never replicate the high stakes of real lies and tend to test technology on healthy individuals (usually students) of above-average intelligence. Children, criminals, the psychotic, the stupid and even those not speaking in their first language (a common issue with benefit claimants) are rarely involved in studies.

The Comparison Question Test: Does It Work and If So How?

polygraphHeinz and Suzanne Offe have just published a paper in Law and Human Behavior, in which they present the results of a study exploring when and how the controversial Control Question Test works in polygraph testing.

The logic of the CQT is that innocent subjects will respond more strongly to Control Questions (CQs, which relate to previous history of – or inclination towards – wrong-doing) than to Relevant Questions (RQs, which relate to the particular offence being investigated). Guilty subjects, on the other hand, will, it is theorised, respond more strongly to RQs.

In order for this procedure to be effective, it is claimed, subjects need to be convinced that being judged ‘not guilty’ depends on them giving socially desirable responses to the CQs. Examiners will tell their subjects something along the following lines:

“I want to find out whether you are the sort of person capable of [the crime under investigation] based on your history. So the questions I am going to ask you about your history will allow me to make these judgements about you. Now, tell me if you have ever taken something that was not yours…”.

In reality the explanations are a lot more detailed than this, all designed to raise the anxiety an innocent subject might feel at the prospect of being accused of something they did not do. (Offe and Offe give a detailed example of how this is done in the first appendix to their study.)

However, as Offe and Offe point out, it is debatable whether or not this type of questioning actually does increase the salience of the CQs for subjects.

The researchers set out to test the workings of the CQT by giving a mix of students and law enforcement trainees the opprtunity to steal some money. Participants were allowed to choose for themselves whether or not to steal, making the simulation more realistic. They were then polygraphed under various different conditions, in which the researchers tested whether explaining the CQ in detail made a difference to the ability to discriminate guilty and innocent subjects.

Read on for the results.

Photo credit: pauldwaite, Creative Commons License

Continue reading The Comparison Question Test: Does It Work and If So How?

Increasing Honest Responding on Cognitive Distortions in Child Molesters: The Bogus Pipeline Revisited

science and machinesAn article in the March 2007 issue of Sexual Abuse: A Journal of Research and Treatment presents the results of an experimental comparision between child molesters’ responses on a questionnaire and their responses when attached to a fake lie detector known as a ‘bogus pipeline’. Here’s the abstract:

Questionnaires are relied upon by forensic psychologists, clinicians, researchers, and social services to assess child molesters’ (CMs’) offense-supportive beliefs (or cognitive distortions). In this study, we used an experimental procedure to evaluate whether extrafamilial CMs underreported their questionnaire-assessed beliefs. At time one, 41 CMs were questionnaire-assessed under standard conditions (i.e., they were free to impression manage). At time two, CMs were questionnaire-assessed again; 18 were randomly attached to a convincing fake lie detector (a bogus pipeline), the others were free to impression manage. The results showed that bogus pipeline CMs significantly increased cognitive distortion endorsements compared to their own previous endorsements, and their control counterparts’ endorsements. The findings are the first experimental evidence showing that CMs consciously depress their scores on transparent questionnaires.

The article is interesting on many levels: let’s unpack it a little.

Continue reading Increasing Honest Responding on Cognitive Distortions in Child Molesters: The Bogus Pipeline Revisited

How America became obsessed with the polygraph

ratlieIn a Washington Monthly article (April 07) entitled The Big Lie (How America became obsessed with the polygraph—even though it has never really worked), David Wallace-Wells reviews Ken Alder’s recently published book The Lie Detectors.

[…] The device has been derided by teams of experts as junk science, hardly more reliable than methods of pure chance, barred from the courts, a favorite tool of overzealous investigators and an instrument of state-sponsored vigilantism, a handmaiden to McCarthyism, an accomplice to the pink scare, and a nightmare vision of justice as arbitrary and expansive as the judgment of a totalitarian court, in a box no bigger or more conspicuous than the briefcase of a company man. And yet, as Ken Alder shows in his revealing, colloquial social history The Lie Detectors, by the time scientific scrutiny finally caught up to the scientistic ambition of the device in the late 1980s, generations of Americans had been seduced by it.

The article concludes with a charming quote from G. K. Chesterton:

“Who but a Yankee would think of proving anything from heart-throbs?” asked G. K. Chesterton’s fictional detective, Father Brown. “Why, they must be as sentimental as a man who thinks a woman is in love with him if she blushes.”

Photo credit: niznoz, Creative Commons License

Polygraph use by the Department of Energy

polygraphVia Bruce Schneier, a CRS report for Congress on Polygraph Use by the Department of Energy [pdf] is available on the Federation of American Scientists website.

Extract from the summary:

This report examines how DOE’s new polygraph screening policy has evolved and reviews certain scientific findings with regard to the polygraph’s accuracy. As part of its continuing oversight of DOE’s polygraph program, the 110th Congress could address several issues, including whether DOE’s new screening program is sufficiently focused on a small number of individuals occupying only the most sensitive positions; program implementation; the desirability of further research into scientific validity of the polygraph and possible alternatives to the polygraph; and whether to continue or discontinue polygraph screening.


Photo credit: pauldwaite, Creative Commons license.

New research: Automation of a screening polygraph test increases accuracy

Charles Honts and Susan Amato have just published a study in Psychology Crime and Law that indicates that an automated polygraph test may lead to more accurate results than one administered by a human being. As Honts and Amato explain:

Much of the criticism of polygraph practice has focused on the polygraph examiners […who have been] criticized for a variety of reasons, including, but not limited to: poor training, bias, incompetence, inability to use statistically relevant information, and for being an uncontrollable and unquantifiable variable in the conduct of polygraph tests.

Participants were randomly assigned to lie (‘guilty’) or tell the truth (‘innocent’) conditions. The human version of the test was conducted by an experienced polygraph examiner, and in the automated version the participants were given their questions via audio tape recording.

In this study, around two thirds of the guilty participants who had been tested by a human were correctly judged to be guilty, and 63% of the innocent participants were correctly judged innocent. However, in the automated version, the correct ‘guilty’ decisions went up to 79% and correct ‘innocent’ decisions to 76%. It’s worth noting that the human examiner was not the one who made the decision about guilt or innocence – this was calculated in exactly the same way for both ‘human’ and ‘automated’ condition, via statistical analyses of the polygraph readings.

Here’s the abstract:

The present study examined the effects of automating the Relevant-Irrelevant (RI) psychophysiological detection of deception test within a mock-screening paradigm. Eighty participants, recruited from the local community, took part in the study. Experimental design was a 2 (truthful/deceptive) by 2 (human/automation) factorial. Participants in the deceptive conditions attempted deception on two items of an employment application. Examinations conducted with the automated polygraph examination were significantly more accurate than examinations conducted by the human polygraph examiner. Statistical analyses revealed different patterns of physiological responses to deceptive items depending upon the automation condition. Those results have potentially interesting theoretical implications. The results of the present study are clearly supportive of additional efforts to develop a field application of an automated polygraph examination.


The Lie Detectors: The History of an American Obsession

A new book on the history of the polygraph is out this month. Here’s how the publisher, Free Press, describes “The Lie Detectors: The History of an American Obsession” by science historian Ken Alder:

The story of the lie detector takes us straight into the dark recesses of the American soul. It also leads us on a noir journey through some of the most storied episodes in American history. That is because the device we take for granted as an indicator of guilt or innocence actually tells us more about our beliefs than about our deeds. The machine does not measure deception so much as feelings of guilt or shame. As Ken Alder reveals in his fascinating and disturbing account, the history of the lie detector exposes fundamental truths about our culture: why we long to know the secret thoughts of our fellow citizens; why we believe in popular science; and why America embraced the culture of “truthiness.”

Purchase links:

UPDATE (11 Mar): An interesting review from the New York Times here and an interview with the author on WYNC here.

Credibility Assessment work at the US Dept of Defense

Via Secrecy News (12 Feb), news of a US Department of Defense Directive [pdf] (number 5210.48, issued 25 Jan 07) relating to the polygraph and “credibility assessment”. The latter term is defined as:

The multi-disciplinary field of existing as well as potential techniques and procedures to assess truthfulness that relies on physiological reactions and behavioral measures to test the agreement between an individual’s memories and statements.

The Directive also transfers existing work on polygraphy and credibility assessment (PCA) to the DoD’s Counter Intelligence Field Activity, which will be responsibile for:

5.2.3. Establish[ing] a process to monitor responsible and effective application of PCA examinations within the Department of Defense.
5.2.4. Establish[ing] DoD PCA standards for education, training, certification, quality assurance, and research.
5.2.5. Properly research[ing] and develop[ing] PCA techniques, instrumentation, and technologies before recommending deployment.
[my emphasis]

See also: AntiPolygraph Blog comments on the DoD Polygraph makeover

Latest on UK plans to polygraph sex offenders

UK Home Secretary John Reid is pressing ahead with plans to roll out compulsory polygraph examinations of sex offenders, reports the Sunday Times (28 January):

John Reid is to introduce compulsory lie detector tests for the first time in Britain to assess whether paedophiles are at risk of reoffending.

The home secretary is backing a legal amendment that would allow compulsory polygraph tests to monitor sex offenders after their release from jail. Probation officers would be able to subject paedophiles to tests measuring their breathing, heart rate and sweat to establish whether they were safe to remain in the community.

[…] Reid’s plans for lie detector tests will enable him to make clear his determination to protect the public from paedophiles, regardless of the overcrowding problem in prisons. Home Office sources confirmed that Reid would support a Labour backbench amendment enabling extensive pilot schemes to assess whether compulsory polygraphs can reduce reoffending.

When the tests were first mooted by David Blunkett, the former home secretary, two years ago the idea provoked a cabinet split. So far only volunteers have taken part in the trials, which are therefore less likely to include recidivists.

The new law, part of the National Offender Management Service bill, will give probation officers the power to make tests compulsory.

See also:

  • Deception Blog post from December 06 on the topic, with links to relevant peer reviewed research.

In Memoriam: David Lykken (1928-2006)

Tributes to David Lyyken in the January 2007 issue of the Association for Psychological Science’s Observer (Volume 20, Number 1), from William G. Iacono, Scott O. Lilienfeld, John Furedy, Don Fowles, Thomas J. Bouchard Jr., Gershon Ben Shakar and Richard J. Rose. Whilst readers of this blog may know Lykken best for his work on polygraphy, these tributes highlight his contributions to many other important areas of psychological research.

Hat tip to the Anti-Polygraph Blog!

Antisociality, underarousal and the validity of the Concealed Information Polygraph Test

Can criminals beat the polygraph more often than non-criminals? In this study, Bruno Verschuere and colleagues from Ghent University in Belgium administered Concealed Information Polygraph Tests (aka Guilty Knowledge Tests) to criminals and other male controls. The CIT / GKT is generally considered to be both more theoretically defensible and more accurate (better at correctly discriminating between liars and truth tellers) than other polygraph tests, such as the Control Question Technique.

Verschuere et al.‘s results suggest that offenders respond less strongly to the presentation of information compared to controls, but the authors conclude that the CIT/GKT is still sensitive enough to use with criminals and suspects.



The Concealed Information Polygraph Test has been advocated as the preferred method for the physiological detection of deception. In this study, we further examined the validity of the Concealed Information Test in antisocial individuals. Physiological responding to concealed information was assessed in 48 male prisoners, and compared with responding in 31 male community volunteers. Based upon the association between antisociality and autonomic hyporesponsivity, lower detection rates were expected in the prisoners. Participants were questioned on five personally significant items (e.g., day of birth), instructed to deny recognition of this information, and promised a financial reward when able to hide recognition. Prisoners showed reduced autonomic reactivity in comparison to the community volunteers. This hyporesponsivity had little impact on the sensitivity of the Concealed Information Test. Detection efficiency in the prisoners was significantly above chance (d = 2.67; a = 0.82; 79%), and did not differ significantly from that obtained in the community volunteers (d = 3.04; a = 0.85; 87%). The present data support the validity of the Concealed Information Test in criminal populations. [Abstract © 2006 Elsevier B.V.]

Lie-test plan for sex offenders

From BBC News (1 December). Despite the title of the news item, the effectiveness of polygraphy with sex offenders is probably more about ‘truth facilitation’ than ‘lie detection’.

Sex offenders could face compulsory lie detector tests in future after a pilot project was judged a success. The Home Office will now consult on the scheme, which aims to monitor offenders’ behaviour in the community.

[…] Professor Don Grubin, of Newcastle University, who led the pilot study, told BBC Radio 4’s Today programme the aim was to use the lie-detector tests alongside other measures. “The aim is not to catch offenders out who have re-offended. The aim is to prevent them from re-offending in the first place,” he said. “So we use the lie-detector as part of a broader package of measures to try to understand what offenders are doing, what sort of behaviours they’re engaging in and whether their risk is increasing.”

A few recent references: