A within-statement baseline comparison for detecting lies.

To make veracity judgements in individual cases, practitioners may rely on baselining. That is, they may evaluate a statement relative to a baseline statement that is known to be truthful. We investigated whether a within-statement verbal baseline comparison could enhance discriminatory accuracy. Participants (n = 148) read an alibi statement of a mock suspect and provided a veracity judgement regarding a critical two-hour period within the alibi statement. This critical element was either deceptive or truthful and was embedded into an otherwise truthful story. Half of the participants received additional instructions to use the surrounding truthful elements of the statement as a baseline. Instructing participants to make a within-statement baseline comparison did not improve the accuracy of credibility assessments.

Detainee and layperson's expectations and preferences regarding police interview rooms.

Emerging research on how suspects perceive the physical environment during investigative interviews yields contrasting findings. While previous studies have suggested that a room made to be physically comfortable may be optimal for interviewing suspects, another study found it can instead lead to higher suspicion of the investigator's intentions. The current study examined current detainees' and general population participants' beliefs about a room that resembled a "typical" interview room, and one decorated to be warm, inviting, and comfortable. Participants also provided descriptive information about their perceptions of police interview environments (e.g., preferences, expectations). We hypothesized that the decorated room would elicit higher ratings of suspicion and wariness compared to the "typical" room. Our findings showed that, overall, participants expected to be interviewed in the "typical" room but preferred the decorated one. Contrary to our expectations, they rated the "typical" room higher on feelings of suspicion than the decorated room. The decorated room also corresponded with what participants reported to be an environment that promotes disclosure. These results bode well for conducting investigative interviews in comfortable environments.

Detecting false intentions using unanticipated questions.

The present study investigated whether measurable verbal differences occur when people vocalize their true and false intentions. To test potential differences, we used an experimental set-up where liars planned a criminal act (i.e., installing a virus on a network computer) and truth-tellers a non-criminal act (i.e., installing a new presentation program "SlideDog" on a network computer). Before they could carry out these acts, a confederate intercepted the participant and interviewed them about their intentions and the planning phase by using both anticipated and unanticipated questions. Liars used a cover story to mask their criminal intentions while truth-tellers told the entire truth. In contrast to our hypotheses, both human and automated coding did not show any evidence that liars and truth-tellers differed in plausibility or detailedness. Furthermore, results showed that asking unanticipated questions resulted in lengthier answers than anticipated questions. These results are in line with the mixed findings in the intention literature and suggest that plausibility and detailedness are less diagnostic cues for deception about intentions.

Lie prevalence, lie characteristics and strategies of self-reported good liars.

Meta-analytic findings indicate that the success of unmasking a deceptive interaction relies more on the performance of the liar than on that of the lie detector. Despite this finding, the lie characteristics and strategies of deception that enable good liars to evade detection are largely unknown. We conducted a survey (n = 194) to explore the association between laypeople's self-reported ability to deceive on the one hand, and their lie prevalence, characteristics, and deception strategies in daily life on the other. Higher self-reported ratings of deception ability were positively correlated with self-reports of telling more lies per day, telling inconsequential lies, lying to colleagues and friends, and communicating lies via face-to-face interactions. We also observed that self-reported good liars highly relied on verbal strategies of deception and they most commonly reported to i) embed their lies into truthful information, ii) keep the statement clear and simple, and iii) provide a plausible account. This study provides a starting point for future research exploring the meta-cognitions and patterns of skilled liars who may be most likely to evade detection.

Bootstrapping the P300 in diagnostic psychophysiology: How many iterations are needed?

In psychophysiological research, bootstrapping procedures are often used to classify individual participants. How many iterations are required for a reliable bootstrap test is not universally agreed upon. To investigate the number of iterations needed for a stable bootstrap estimate, we reanalyzed P300 data collected in concealed information test paradigms. We also distinguished between the bootstrap and permutations approaches. We compared results in several studies using 100 versus 1,000 versus 10,000 iterations in the bootstrap, and we concluded that 100 iterations were adequate as results from all three iteration numbers correlated highly.

Strong, but Wrong: Lay People's and Police Officers' Beliefs about Verbal and Nonverbal Cues to Deception.

The present study investigated the beliefs of students and police officers about cues to deception. A total of 95 police officers and 104 undergraduate students filled out a questionnaire addressing beliefs about cues to deception. Twenty-eight verbal cues were included in the questionnaire, all extracted from verbal credibility assessment tools (i.e., CBCA, RM, and SCAN). We investigated to what extent beliefs about nonverbal and verbal cues of deception differed between lay people (students) and police officers, and whether these beliefs were in agreement with objective cues known from research. Both students and police officers believed the usual stereotypical, but non-diagnostic (nonverbal) cues such as gaze aversion and increased movement to be indicative of deception. Yet, participants were less inclined to overestimate the relationship between verbal cues and deception and their beliefs fitted better with what we know from research. The implications of these findings for practice are discussed.

Scientific Content Analysis (SCAN) Cannot Distinguish Between Truthful and Fabricated Accounts of a Negative Event.

The Scientific Content Analysis (SCAN) is a verbal veracity assessment method that is currently used worldwide by investigative authorities. Yet, research investigating the accuracy of SCAN is scarce. The present study tested whether SCAN was able to accurately discriminate between true and fabricated statements. To this end, 117 participants were asked to write down one true and one fabricated statement about a recent negative event that happened in their lives. All statements were analyzed using 11 criteria derived from SCAN. Results indicated that SCAN was not able to correctly classify true and fabricated statements. Lacking empirical support, the application of SCAN in its current form should be discouraged.

Deception detection with behavioral, autonomic, and neural measures: Conceptual and methodological considerations that warrant modesty.

The detection of deception has attracted increased attention among psychological researchers, legal scholars, and ethicists during the last decade. Much of this has been driven by the possibility of using neuroimaging techniques for lie detection. Yet, neuroimaging studies addressing deception detection are clouded by lack of conceptual clarity and a host of methodological problems that are not unique to neuroimaging. We review the various research paradigms and the dependent measures that have been adopted to study deception and its detection. In doing so, we differentiate between basic research designed to shed light on the neurocognitive mechanisms underlying deceptive behavior and applied research aimed at detecting lies. We also stress the distinction between paradigms attempting to detect deception directly and those attempting to establish involvement by detecting crime-related knowledge, and discuss the methodological difficulties and threats to validity associated with each paradigm. Our conclusion is that the main challenge of future research is to find paradigms that can isolate cognitive factors associated with deception, rather than the discovery of a unique (brain) correlate of lying. We argue that the Comparison Question Test currently applied in many countries has weak scientific validity, which cannot be remedied by using neuroimaging measures. Other paradigms are promising, but the absence of data from ecologically valid studies poses a challenge for legal admissibility of their outcomes.

The role of frontal EEG asymmetry in post-traumatic stress disorder.

Frontal alpha asymmetry, a biomarker derived from electroencephalography (EEG) recordings, has often been associated with psychological adjustment, with more left-sided frontal activity predicting approach motivation and lower levels of depression and anxiety. This suggests high relevance to post-traumatic stress disorder (PTSD), a disorder comprising anxiety and dysphoria symptoms. We review this relationship and show that frontal asymmetry can be plausibly linked to neuropsychological abnormalities seen in PTSD. However, surprisingly few studies (k = 8) have directly addressed frontal asymmetry in PTSD, mostly reporting that trait frontal asymmetry has little (if any) predictive value. Meanwhile, preliminary evidence suggest that state-dependent asymmetry during trauma-relevant stimulation distinguishes PTSD patients from resilient individuals. Thus, exploring links between provocation-induced EEG asymmetry and PTSD appears particularly promising. Additionally, we recommend more fine-grained analyses into PTSD symptom clusters in relation to frontal asymmetry. Finally, we highlight hypotheses that may guide future research and help to fully apprehend the practical and theoretical relevance of this biological marker.

Memory detection with the Concealed Information Test: a meta analysis of skin conductance, respiration, heart rate, and P300 data.

The Concealed Information Test (CIT) uses psychophysiological measures to determine the presence or absence of crime-related information in a suspect's memory. We conducted a meta-analysis on the validity of the CIT based on four physiological measures-skin conductance response (SCR), respiration line length (RLL), changes in heart rate (HR), and enhanced amplitudes of the P300 component of the event-related potential (P300). This meta-analysis relied on laboratory studies that used either the mock-crime or the personal-item paradigm. Results showed a mean effect size (d*) of 1.55 for SCR, 1.11 for RLL, 0.89 for HR, and 1.89 for P300. However, P300 outperformed SCR only in the personal-item paradigm, but not in the mock-crime paradigm. Motivation level, number of questions, publication year, and the inclusion of innocent participants emerged as significant moderators for the SCR, while only the type of paradigm used moderated the P300 effect.

Frontal EEG asymmetry as predictor of physiological responses to aversive memories.

Evidence suggests that asymmetry in frontal electrical activity predicts responses to aversive experiences, such that higher left-sided activity might dampen responses to trauma reminders. We measured frontal asymmetry at rest and during viewing of a trauma film, and assessed startle responses to film-reminder images. To explore potential moderators, we compared two films (Study 1; N = 64) and modulated reappraisal (Study 2; N = 72). As expected, left frontal activation during film viewing predicted dampened responses in individuals who viewed a staged road accident. However, this effect tended to be reversed when a genocide documentary was used. In Study 2, all participants viewed the genocide film. Left frontal activity at rest again predicted higher startle responses, while reappraisal did not moderate the effects. Thus, the type of trauma film plays a crucial role in the effects of frontal asymmetry, which warrants further critical investigation.

A comment on Farwell (2012): brain fingerprinting: a comprehensive tutorial review of detection of concealed information with event-related brain potentials.

In a recent issue of Cognitive Neurodynamics Farwell (Cogn Neurodyn 6:115-154, 2012) published a comprehensive tutorial review of the use of Event Related Brain Potentials (ERP) in the detection of concealed information. Farwell's review covered much of his own work employing his "brain fingerprinting" technology. All his work showed a 100 % accuracy rate in detecting concealed information. We argue in this comment that Farwell (Cogn Neurodyn 6:115-154, 2012) is misleading and misrepresents the scientific status of brain fingerprinting technology.

Detecting concealed information from groups using a dynamic questioning approach: simultaneous skin conductance measurement and immediate feedback.

Lie detection procedures typically aim at determining the guilt or innocence of a single suspect. The Concealed Information Test (CIT), for example, has been shown to be highly successful in detecting the presence or absence of crime-related information in a suspect's memory. Many of today's security threats, however, do not come from individuals, but from organized groups such as criminal organizations or terrorist networks. In this study, we tested whether a plan of an upcoming mock terrorist attack could be extracted from a group of suspects using a dynamic questioning approach. One-hundred participants were tested in 20 groups of 5. Each group was asked to plan a mock terrorist attack based on a list of potential countries, cities, and streets. Next, three questions referring to the country, city, and street were presented, each with five options. Skin conductance in all five members of the group was measured simultaneously during this presentation. The dynamic questioning approach entailed direct analysis of the data, and if the average skin conductance of the group to a certain option exceeded a threshold, this option was followed up, e.g., if the reaction to the option "Italy" exceeded the threshold, this was followed up by presenting five cities in Italy. Results showed that in 19 of the 20 groups the country was correctly detected using this procedure. In 13 of these remaining 19 groups the city was correctly detected. In 7 of these 13, the street was also correctly detected. The question about the country resulted in no false positives (out of 20), the question about the city resulted in two false positives (out of 19), while the question about the streets resulted in two false positives (out of 13). Furthermore, the two false positives at the city level also yielded a false positive at the street level. Even though effect sizes were only moderate, these results indicate that our dynamic questioning approach can help to unveil plans about a mock terrorist attack.

Emotional memory for central and peripheral details in children with callous-unemotional traits.

A limited number of studies have shown that adults and adolescents with psychopathic traits suffer from emotional memory impairment. The present study examined whether this finding could be replicated in a sample of children between 8 and 12 years of age with callous-unemotional (CU) traits. Children with high CU traits (n=24) were compared with children with low CU traits (n=18) with regard to performance on a peripheral memory recognition test that examined memory for central and peripheral components of neutral and negative pictures. Results showed that overall recognition rates did not differ between the high- and low-CU groups. For negative pictures, both groups demonstrated better recognition of the central component at the expense of the peripheral component, while for neutral pictures, the peripheral component was better recognized than the central component. This study is the first to demonstrate that children with high CU traits do not suffer from an impaired emotional memory.

The origin of children's implanted false memories: memory traces or compliance?

A longstanding question in false memory research is whether children's implanted false memories represent actual memory traces or merely result from compliance. The current study examined this question using a response latency based deception task. Forty-five 8-year-old children received narratives about a true (first day at school) and false event (hot air balloon ride). Across two interviews, 58/32% of the participants developed a partial/full false memory. Interestingly, these children also showed higher false recall on an unrelated DRM paradigm compared to children without a false memory. The crucial finding, however, was that the results of the deception task revealed that children with partial and full false memories were faster to confirm than to deny statements relating to the false event. This indicates that children's implanted false memories reflect actual memory traces, and are unlikely to be explained by mere compliance.

The ease of lying.

Brain imaging studies suggest that truth telling constitutes the default of the human brain and that lying involves intentional suppression of the predominant truth response. By manipulating the truth proportion in the Sheffield lie test, we investigated whether the dominance of the truth response is malleable. Results showed that frequent truth telling made lying more difficult, and that frequent lying made lying easier. These results implicate that (1) the accuracy of lie detection tests may be improved by increasing the dominance of the truth response and that (2) habitual lying makes the lie response more dominant.

Extracting concealed information from groups.

Lie detection procedures are typically aimed at determining guilt or innocence of a single suspect. Serious security threats, however, often involve groups, such as terrorist networks or criminal organizations. In this report, we describe a variant of the skin conductance-based Concealed Information Test (CIT) that allows for the extraction of critical information from such groups. Twelve participants were given information about an upcoming (mock) terrorist attack, with specific instructions not to reveal this information to anyone. Next, each subject was subjected to a CIT, with questions pertaining to the details of the attack. Results showed that for every question, the average skin conductance response to the correct answer option differed significantly (p < 0.05) from those to all other options. These results show that the information about the upcoming attack could be extracted from the group of terror suspects as a whole.

Children's suggestion-induced omission errors are not caused by memory erasure.

We explored whether children's suggestion-induced omission errors are caused by memory erasure. Seventy-five children were instructed to remove three pieces of clothing from a puppet. Next, they were confronted with evidence falsely suggesting that one of the items had not been removed. During two subsequent interviews separated by one week, children had to report which pieces of clothing they had removed. Children who during both interviews failed to report that they had removed the pertinent item (i.e., omission error; n=24) completed a choice reaction time task. In this task, they were presented with different clothing items. For each item, children had to indicate whether or not they had removed it. Significantly more errors were made for those removed items that children failed to report than for those they had not removed. This indicates that children's suggestion-based omission errors are not due to erasure of memories.

The contribution of mere recognition to the p300 effect in a concealed information test.

In two experiments, we investigated the role of mere recognition in a P300 based CIT. Mere recognition was isolated by having participants respond based on an irrelevant dimension of the stimuli. In Experiment 1 stimuli consisted of familiar and unfamiliar faces, with a dot placed on the left or the right cheek. Participants responded according to dot location. In the second experiment, participants were presented with autobiographical information, alternated with irrelevant stimuli, while instructed to respond based on the case of the stimuli. Results showed that with both familiar faces, and autobiographical information, mere recognition was sufficient to elicit a P300.

Sex offender management using the polygraph: a critical review.

Reducing recidivism is a central goal in the treatment of sex offenders. In Europe, there is an increased interest in using the polygraph ("lie detector") as a tool in the treatment and risk assessment of convicted sex offenders. This interest originated from optimistic reports by American clinicians who argued that polygraph testing in the treatment of sex offenders is akin to urine analysis in the treatment of drug addiction. In this article, we critically examine the validity and utility of post-conviction sex offender polygraph testing. Our review shows that the available evidence for the claims about the clinical potential of polygraph tests is weak, if not absent. We conclude that portraying post-conviction polygraph testing as analogous to urine analysis is inaccurate, misleading, and ultimately, risky.