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

Psychology and the lie detector industry: A fifty-year perspective

Fifty years ago, in a trenchant analysis that challenged applied lie detection theory and science, David Lykken (1974) brought polygraphic interrogation methods to the attention of academia with the hope that these techniques would come under the purview of psychology and psychophysiology. In this perspective, I examine how this application of psychophysiology has evolved over the last half century and how its status has changed for 1) the comparison (control) question test (CQT), used in forensic applications; 2) polygraph screening tests, used to evaluate examinee integrity; and 3) the concealed information technique (CIT), used to assess recognition memory of crime details. The criticisms of the CQT and screening tests advanced by Lykken have been amplified and focused by the academic community over the last half century. However, this has had little effect on how these methods are practiced and has not curtailed their use. Although most private sector employee screening tests are now prohibited, personnel screening of government employees has increased, and screening tests of sex offenders are now commonplace. Even though the CIT has captured the interest of psychophysiologists as a scientifically defensible technique, its field use is negligible. A primary purpose of polygraphic interrogations continues to be the extraction of admissions and confessions. The lack of change in the polygraph testing status quo stems in large part from unwavering government support for the use of these methods. As a result, polygraph theory and research support continues to rest on shaky ground while practice continues unfettered by valid criticism.

Unveiling the efficacy of the feedback concealed information test in collaborative crime detection

Collaborative crime poses severe social hazards. In collaborative crime scenarios, previous studies have indicated that perpetrators' collaborative encoding can impair the detection efficiency of P300-based complex trial protocols due to the collaborative encoding deficit. The feedback concealed information test (fCIT), a unique variation of the concealed information test, provides participants with feedback on how well they conceal information from memory. The fCIT, which has proven to be highly efficient, detects concealed information using recognition P300 along with feedback-related event-related potentials, and reflects the subject's motivation to conceal. However, no studies have examined the fCIT's effectiveness in identifying collaborative criminals. We propose that the fCIT's efficiency persists in cases of collaborative crime and test this hypothesis using a sample of 48 participants. The participants in the collaborative groups were instructed to have hushed conversations about theft to simulate the collaborative crime process. Subsequently, they completed the fCIT. The findings indicate a significant decline in recognition P300's detection efficiency when participants committed crimes collaboratively. Nevertheless, the detection efficiency of feedback P300 and feedback-related negativity remained high. This study's outcomes illustrate the capacity of the fCIT to detect perpetrators involved in collaborative crime.

Diagnosing eyewitness identifications with reaction time-based concealed information test: the effect of observation time

Eyewitness identification procedures rely heavily on explicit identification from lineups. Lineups have been criticized because they have a considerable error rate. We tested the potential of implicit identifications in a Concealed Information Test (CIT) as an alternative. Previous experiments have suggested that implicit identification procedures might be suited when viewing conditions were favorable. In two experiments, mock eyewitnesses (Ns = 94, 509) witnessed a videotaped mock theft with longer or shorter observation time. We derived eyewitness identifications either implicitly from CIT reaction times or explicitly from simultaneous photo lineups. In Experiment 2, we also manipulated perpetrator presence. In both experiments, the perpetrator-present CIT showed capacity to diagnose face recognition, with large effect sizes (d_E1 = 0.85 [0.51; 1.18]; d_E2 = 0.74 [0.52; 0.96]), as expected. Unexpectedly, no moderation by observation time was found. In line with our hypothesis, no CIT effect emerged in the perpetrator-absent condition, indicating the absence of recognition (d_E2 = 0.02 [- 0.17; 0.20]). We found no compelling evidence that one method would outperform the other. This work adds to accumulating evidence that suggests that, under favorable viewing conditions and replication provided, the RT-CIT might be diagnostic of facial recognition, for example when witnesses are hesitant of making an explicit identification. Future work might investigate conditions that affect performance in one, but not the other identification method.

The role of conflict processing mechanism in deception responses

A considerable number of studies have described the potential neural mechanism of deception, but most deception studies have relied upon deception from experimental supervisor instruction. Experimental control (participants follow instructions to deceive without any risk) means that the deception occurs in a way that does not come close to the real deception. In the current study, a neural imaging experiment on deception closer to the real deception was conducted. Event-related potential (ERP) and event-related spectral perturbation (ERSP) techniques were used to explore the neural mechanism of deception. The results showed that deceptive response evoked larger medial-frontal negativity (MFN) and smaller response-locked positivity (RLP) than truthful response. We interpret these findings to indicate that conflict detection and emotional processing are associated with deception. In addition, magnitudes of alpha and beta oscillations after the deceptive response were significantly smaller than those after the truthful response, demonstrating that deception is associated with neural oscillations reflecting conflict adjustment. The results comprehensively characterized the physiological properties of the brain oscillations elicited by a deceptive response and provided a theoretical foundation for detection in practical applications.

Concealed identity information detection with pupillometry in rapid serial visual presentation

The concealed information test (CIT) relies on bodily reactions to stimuli that are hidden in mind. However, people can use countermeasures, such as purposely focusing on irrelevant things, to confound the CIT. A new method designed to prevent countermeasures uses rapid serial visual presentation (RSVP) to present stimuli on the fringe of awareness. Previous studies that used RSVP in combination with electroencephalography (EEG) showed that participants exhibit a clear reaction to their real first name, even when they try to prevent such a reaction (i.e., when their name is concealed information). Because EEG is not easily applicable outside the laboratory, we investigated here whether pupil size, which is easier to measure, can also be used to detect concealed identity information. In our first study, participants adopted a fake name, and searched for this name in an RSVP task, while their pupil sizes were recorded. Apart from this fake name, their real name and a control name also appeared in the task. We found pupil dilation in response to the task-irrelevant real name, as compared to control names. However, while most participants showed this effect qualitatively, it was not statistically significant for most participants individually. In a second study, we preregistered the proof-of-concept methodology and replicated the original findings. Taken together, our results show that the current RSVP task with pupillometry can detect concealed identity information at a group level. Further development of the method is needed to create a valid and reliable concealed identity information detector at the individual level.

The effect of mental countermeasures on a novel brain-based feedback concealed information test

The feedback concealed information test (fCIT) is a novel form of the CIT, providing participants with feedback regarding their memory concealment performance. The fCIT utilizes event-related potentials (recognition-P300 and feedback-related event-related potentials) and has been shown to provide high efficiency in detecting information concealment. However, it is unclear how well the fCIT performs in the presence of mental countermeasures. To address this question, participants were trained to use countermeasures during fCIT. Results showed that the recognition-P300 efficiency decreased when participants used countermeasures. However, the efficiencies of feedback-related negativity and feedback-P300 were unchanged, with feedback-P300 still showing a high detection efficiency (AUC = 0.86) during countermeasures. These findings demonstrate the potential of fCIT for subverting countermeasures.

Detecting concealed information using functional near-infrared spectroscopy (fNIRS) combined with skin conductance, heart rate, and behavioral measures

In this study, brain imaging data from functional near-infrared spectroscopy (fNIRS) associated with skin conductance response (SCR), heart rate (HR), and reaction time (RT) were combined to determine if the combination of these indicators could improve the efficiency of deception detection in concealed information test (CIT). During the CIT, participants were presented with a series of names and cities that served as target, probe, or irrelevant stimuli. In the guilty group, the probe stimuli were the participants' own names and hometown cities, and they were asked to deny this information. Our results revealed that probe items were associated with longer RT, larger SCR, slower HR, and higher oxyhemoglobin (HbO) concentration changes in the inferior prefrontal gyrus (IFG), middle frontal gyrus (MFG), and the superior frontal gyrus (SFG) compared with irrelevant items for participants in the guilty group but not in the innocent group. Furthermore, our results suggested that the combination of RT, SCR, HR, and fNIRS indicators could improve the deception detection efficiency to a very high area under the ROC curve (0.94) compared with any of the single indicators (0.74-0.89). The improved deception detection efficiency might be attributed to the reduction of random error and the diversiform underlying the psychophysiological mechanisms reflected by each indicator. These findings demonstrate a feasible way to improve the deception detection efficiency by using combined multiple indicators.

Aging reduces EEG markers of recognition despite intact performance: Implications for forensic memory detection

ERP-based forensic memory detection is based on the logic that guilty suspects will hold incriminating knowledge about crimes they have committed, and therefore should show parietal ERP positivities related to recognition when presented with reminders of their crimes. We predicted that such forensic memory detection might however be inaccurate in older adults, because of changes to recognition-related brain activity that occurs with aging. We measured both ERPs and EEG oscillations associated with episodic old/new recognition and forensic memory detection in 30 younger (age < 30) and 30 older (age > 65) adults. EEG oscillations were included as a complementary measure which is less sensitive to temporal variability and component overlap than ERPs. In line with predictions, recognition-related parietal ERP positivities were significantly reduced in the older compared to younger group in both tasks, despite highly similar behavioural performance. We also observed aging-related reductions in oscillatory markers of recognition in the forensic memory detection test, while the oscillatory effects associated with episodic recognition were similar across age groups. This pattern of results suggests that while both forensic memory detection and episodic recognition are accompanied by aging-induced reductions in parietal ERP positivities, these reductions may be caused by non-overlapping mechanisms across the two tasks. Our findings suggest that EEG-based forensic memory detection tests are less valid in older than younger populations, limiting their practical applications.

Does hostile intent cause physiological changes? An airport security check simulation experiment

The present research was aimed at investigating in a simulation experiment whether the initiation of a hostile project in an environment akin to airport security checkpoints would translate in variation of cardiac activity. Twenty-three participants (eight women) enrolled as mock passengers had to make several traverses of a security checkpoint while carrying luggage containing either a neutral or a falsely dangerous item. The traverses with the falsely dangerous item were associated with an elevation of heart rate and higher drops of heart rate variability than the traverses with the neutral item. These effects were more salient for the first traverses. Implication of results for security management and the role of arousal and mental workload in threat detection are discussed.

A practical approach to sexual abuse allegations: Netherlands Expert Committee for Equivocal Sexual Abuse Allegations

Equivocal sexual abuse allegations are those in which the details of the alleged offence(s) are uncertain. The circumstances are ambiguous, there is limited evidence, and it is unclear how police investigations should proceed. This article discusses the challenges such allegations pose for police, prosecution, judges and mental health experts, and advocates for the use of multidisciplinary expert opinion during the investigation. The practical application of this approach by the Netherlands Expert Committee for Equivocal Sexual Abuse Allegations (LEBZ) is described, which has assessed over 900 cases since its inception in 1999. The LEBZ approach represents a significant innovation in police and criminal justice responses to equivocal allegations of sexual assault, which warrants consideration in other jurisdictions.

Brain-based concealed memory detection is driven mainly by orientation to salient items

In the pursuit of new methods for concealed memory detection, event-related potential components (ERP) have been placed at the forefront of research. No method, however, is scientifically complete without a theory and the present study therefore aimed to unravel the cognitive processes underlying these ERPs (i.e., orienting and arousal inhibition). This was accomplished by using a Concealed Information Test (CIT) in which participants were once motivated to conceal and once motivated to reveal their identity. The results showed a similarly strong P3 CIT effect in the two motivational conditions, which was enhanced for high salience compared to low salience identity items. Similar results were observed when using a multivariate machine-learning algorithm - suggesting that brain-based concealed memory detection is driven mainly by orientation to salient stimuli, rather than by arousal inhibition. In addition, the algorithm, trained and tested on the ERPs of different identity items, achieved detection rates exceeding those achieved by the P3. This implies that CIT researchers and practitioners could potentially rely on the entire ERP waveform instead of a-priori selecting separate components. Together these results enrich current understanding of the mechanisms underlying neurophysiological responding to concealed information and pave the way for novel and powerful algorithms which could be used in real-life forensic investigations.

The Electrocortical Signature of Successful and Unsuccessful Deception in a Face-to-Face Social Interaction

Deceptive behavior, and the evaluation of others' behavior as truthful or deceptive, are crucial aspects of human social interaction. We report a study investigating two participants in a social interaction, performing a deception task. The first participant, the "informant," made true or false autobiographical statements. The second participant, the "detective," then classified these statements as truth or lie. Behavioral data showed that detectives performed slightly above chance and were better at correctly identifying true as compared with deceptive statements. This presumably reflects the "truth bias": the finding that individuals are more likely to classify others' statements as truthful than as deceptive - even when informed that a lie is as likely to be told as the truth. Electroencephalography (EEG) was recorded from the informant. Event-related potential (ERP) analysis revealed a smaller contingent negative variation (CNV) preceding "convincing" statements (statements classified as true by the detective) compared to "unconvincing" statements (statements classified as lie by the detective) - irrespective of whether the statements were actually truthful or deceptive. This finding suggests a distinct electrocortical signature of "successful" compared to "unsuccessful" deceptive statements. One possible explanation is that the pronounced CNV indicates the individuals' higher "cognitive load" when processing unconvincing statements.

Neural mechanisms of deception in a social context: an fMRI replication study

Deception is a form of manipulation aimed at misleading another person by conveying false or truthful messages. Manipulative truthful statements could be considered as sophisticated deception and elicit an increased cognitive load. However, only one fMRI study reported its neural correlates. To provide independent evidence for sophisticated deception, we carried out an fMRI study replicating the experimental paradigm and Bayesian statistical approach utilized in that study. During the experiment, participants played a game against an opponent by sending deliberate deceptive or honest messages. Compared to truth-telling, deceptive intentions, regardless of how they were fulfilled, were associated with increased BOLD signals in the bilateral temporoparietal junction (TPJ), left precuneus, and right superior temporal sulcus (STS). The right TPJ participates in the attribution of mental states, acting in a social context, and moral behaviour. Moreover, the other revealed brain areas have been considered nodes in the theory of mind brain neural system. Therefore, the obtained results reflect an increased demand for socio‑cognitive processes associated with deceptive intentions. We replicated the original study showing the involvement of the right TPJ and expanded upon it by revealing the involvement of the left TPJ, left precuneus and right STS in actions with deceptive intentions.

Seen this scene? Scene recognition in the reaction-time Concealed Information Test

Detecting a suspect's recognition of a crime scene (e.g., a burgled room or a location visited for criminal activity) can be of great value during criminal investigations. Although it is established that the Reaction-Time Concealed Information Test (RT-CIT) can determine whether a suspect recognizes crime-related objects, no research has tested whether this capability extends to the recognition of scenes. In Experiment 1, participants were given an autobiographic scene-based RT-CIT. In Experiment 2, participants watched a mock crime video before completing an RT-CIT that included both scenes and objects. In Experiment 3, participants completed an autobiographic scene-based RT-CIT, with half instructed to perform a physical countermeasure. Overall, the findings showed that an equivalent RT-CIT effect can be found with both scene and object stimuli and that RT-CITs may not be susceptible to physical countermeasure strategies, thereby increasing its real-world applicability.

Increased Motor Cortex Excitability for Concealed Visual Information

Abstract. Deceptive behavior involves complex neural processes involving the primary motor cortex. The dynamics of this motor cortex excitability prior to lying are still not well understood. We sought to examine whether corticospinal excitability can be used to suggest the presence of deliberately concealed information in a modified version of the guilty knowledge test (GKT). Participants pressed keys to either truthfully or deceitfully indicate their familiarity with a series of faces. Motor-evoked potentials (MEPs) were recorded during response preparation to measure muscle-specific neural excitability. We hypothesized that MEPs would increase during the deceptive condition not only in the lie-telling finger but also in the suppressed truth-telling finger. We report a group-level increase in overall corticospinal excitability 300 ms following stimulus onset during the deceptive condition, without specific activation of the neural representation of the truth-telling finger. We discuss cognitive processes, particularly response conflict and/or automated responses to familiar stimuli, which may drive the observed nonspecific increase of motor excitability in deception.

An experiment to assess emotional and physiological arousal and personality correlates while imagining deceit

In order to examine how personality traits, emotional arousal and physiological arousal affect deception confidence, students (N = 102) completed the Eysenck Personality Questionnaire-Revised (EPQ-R) as well as stress and deception tasks while their heart rate variability was measured. Findings indicated psychoticism did not moderate how physiologically aroused participants were while viewing emotionally salient stimuli (video of a road traffic accident) or the thought of enacting deceit, although this came close to significance. However, participants (particularly males) higher in psychoticism reported less subjective distress after imagining enacting deceit than those lower on psychoticism. Extroversion had no impact on physiological arousal when viewing emotionally salient stimuli or thinking about enacting deceit. However, extroverts reported more subjective distress after thinking about enacting deceit than introverts. Also, deception confidence was not correlated to any of these variables. Future research could examine a sample higher in psychoticism and how this trait impacts deception confidence.

Testing a potential alternative to traditional identification procedures: Reaction time-based concealed information test does not work for lineups with cooperative witnesses

Direct eyewitness identification is widely used, but prone to error. We tested the validity of indirect eyewitness identification decisions using the reaction time-based concealed information test (CIT) for assessing cooperative eyewitnesses' face memory as an alternative to traditional lineup procedures. In a series of five experiments, a total of 401 mock eyewitnesses watched one of 11 different stimulus events that depicted a breach of law. Eyewitness identifications in the CIT were derived from longer reaction times as compared to well-matched foil faces not encountered before. Across the five experiments, the weighted mean effect size d was 0.14 (95% CI 0.08-0.19). The reaction time-based CIT seems unsuited for testing cooperative eyewitnesses' memory for faces. The careful matching of the faces required for a fair lineup or the lack of intent to deceive may have hampered the diagnosticity of the reaction time-based CIT.

An intra-individual approach for detecting evaluation with event-related potentials

The P3-based concealed information test (CIT) is an accurate indirect measure of non-evaluative memories (e.g., knowledge of an incriminating item). Less clear and established, however, is the accuracy of indirect measures that rely on the P3-like late positive potentials (LPPs) in discriminating evaluative (e.g., pleasant or unpleasant) memories. Using an LPP-based evaluative oddball paradigm in which participants were truthful on half of the trials about their evaluation toward pictures and concealed their evaluation on the other half of trials toward pictures, we applied an intra-individual Bayesian scheme to classify whether participants' evaluations were congruent or incongruent with a preceding context. LPPs were predictably larger to evaluatively incongruent than congruent pictures, and this LPP effect was reduced during misreporting presumably because of enhanced cognitive load. Notably, across two experiments the sensitivity (80%) was respectable during truth telling, but poor during concealment (sensitivity = 35%). Taken together, these data suggest that indirect measures such as the LPP-based evaluative oddball may be useful for detecting individual evaluation, but more work is warranted that explores conditions under which concealment of evaluation may be more accurately assessed.

Using Polygraph to Detect Passengers Carrying Illegal Items

The present study examined the effectiveness of a Modified-Comparison Questions Technique, used in conjunction with the polygraph, to differentiate between common travelers, drug traffickers, and terrorists at transportation hubs. Two experiments were conducted using a mock crime paradigm. In Experiment 1, we randomly assigned 78 participants to either a drug condition, where they packed and lied about illicit drugs in their luggage, or a control condition, where they did not pack or lie about any illegal items. In Experiment 2, we randomly assigned 164 participants to one of the two conditions in Experiment 1 or an additional bomb condition, where they packed and lied about a bomb in their luggage. For both experiments, we assessed participants’ RR interval, heart rate, peak-to-peak amplitude of Galvanic Skin Response (GSR) and all three combined, using Discriminant Analyses to determine the classification accuracy of participants in each condition. In both experiments, we found decelerated heart rates and increased peak-to-peak amplitude of GSR in guilty participants when lying in response to questions regarding their crime. We also found accurate classifications of participants, in both Experiment 1 (drug vs. control: 84.2% vs. 82.5%) and Experiment 2 (drug vs. control: 82:1% vs. 95.1%; bomb vs. control: 93.2% vs. 95.1%; drug vs. bomb: 92.3% vs. 90.9%), above chance level. These findings indicate that Modified-CQT, combined with a polygraph test, is a viable method for investigating suspects of drug trafficking and terrorism at transportation hubs such as train stations and airports.

Methodological improvements of the association-based concealed information test

The Association-Based Concealed Information Test (A-CIT) is a deception-detection method, in which participants categorize personally relevant items (e.g., their own surnames) as probes together with categorically similar but irrelevant items (e.g., others' surnames) by one key press A, while categorizing self-referring "inducer" items (e.g., "MINE" or "MY NAME") with an alternative key press B, thereby establishing an association between self-relatedness and B and an incongruence between the self-relatedness of probes and A (Lukács, Gula, Szegedi-Hallgató, & Csifcsák, 2017). The A-CIT's sensitivity to concealed information is reflected in an incongruence effect: slower responses to probes than to other surnames. To increase the relevance of categories, between trials of the original A-CIT, category-to-response mappings switched or repeated unpredictably. This, however, could have diminished incongruence effects, as the response labels were presented in the corners of the display, veering spatial attention away from the items at screen center. In the present online study (n = 294), we therefore tested two improved versions of the A-CIT that do not require spatial attention shifts to and from peripheral labels. One improved version presents per trial only one category label at screen center and requires comparison to the currently presented item. The other improved version is based on the Identification Extrinsic Affective Simon Task (ID-EAST), in which item categorization switches (or repeats) based on colors versus meanings of the central items. Both new versions outperformed the original A-CIT.

Why Behavioral Indicators May Fail to Reveal Mental States: Individual Differences in Arousal-Movement Pattern Relationships

It is commonly assumed that behavior reflects the mental states of individuals. However, recent attempts to detect human states of mind via behavioral indicators have not always been successful; behavioral indicators may be unreliable and invalid. In this study we show that one of the common behavioral indicators, change in the overall amount of movement, correlated well with changes in the skin conductance level (SCL) at the group level, which reflects changes in arousal. At the individual level, however, changes in the SCL were related to movement patterns only in about half of the individuals. It is also noteworthy that the level of movement-SCL correlation was very highly predictable by certain social and cognitive characteristics of the individuals. Our results suggest that behavioral indicators may in many cases fail to predict mental states at the individual level.

Reaction time-based Concealed Information Test in eyewitness identification is moderated by picture similarity but not eyewitness cooperation

The reaction time-based Concealed Information Test (RT-CIT) has high validity in assessing recognition of critical information. Findings on its usefulness for diagnosing face recognition in eyewitnesses are inconsistent. Experiment 1 (N = 82) tested whether closely matching the faces of the probes and irrelevants, as required for a fair lineup, undermines RT-CIT usefulness. Preregistered Experiments 2a and 2b (Ns = 48), tested the role of eyewitness cooperativeness for RT-CIT validity. All participants watched a mock crime video and then completed an RT-CIT. As expected, the usefulness of the RT-CIT was moderated by picture similarity, with better detection for non-matched faces. Unexpectedly, eyewitness cooperation (conceal vs. reveal recognition), did not affect the validity of the RT-CIT. A large CIT effect observed in Experiment 2b further suggested that-even with matched faces-the RT-CIT might be of use when encoding conditions during the crime were favorable. Cases in which witnesses are unwilling or afraid to make an explicit identification might concern another possible application.

The language of lies: a preregistered direct replication of Suchotzki and Gamer (2018; Experiment 2)

Is lying in a different language easier or more difficult? The Emotional Distance and the Cognitive Load hypothesis give competing answers. Suchotzki and Gamer measured the time native German speakers needed to initiate honest and deceptive answers to German and English questions. Lie-truth differences in RTs were much smaller for the foreign compared to the native language. In our preregistered replication study in native Dutch speakers, we found that lie-truth differences in RTs were moderately smaller when participants were tested in English than when tested in Dutch. These findings indicate that people struggle with quickly retrieving the truth in another language, and that foreign language use may diminish lie-truth differences.

Testing the applied potential of the Sheffield Lie Test

The Sheffield Lie Test (SLT) has been frequently used in laboratory research investigating basic mechanisms of deception. Its applied potential as a lie detection tool has been contested. The current two experiments used a reaction time SLT and investigated whether it can discriminate between participants who committed a mock crime and participants who performed an everyday activity. Results of the first experiment revealed that guilty participants (n = 32) took longer and committed more errors when having to deceptively deny the mock crime and deceptively confirm having performed the everyday activity in contrast to truthfully admitting the mock crime and denying the everyday activity. Innocent participants (n = 29) showed the reversed pattern. Individual Cohen's d's and the area under the ROC curve revealed a high above chance discrimination between both groups. In a second experiment, we repeated this procedure, yet participants were now given a more elaborate explanation of the alibi activity that all should pretend to have done. Although results still revealed the expected pattern in innocent participants (n = 48), the effect was not significant any more for the guilty participants (n = 46). Accordingly, classification accuracies also dropped. These two experiments demonstrate the applied potential of the SLT, yet at the same time its severe limitations. Potential solutions and suggestions for future research will be discussed.

Effect of negative motivation on the behavioral and autonomic correlates of deception

In forensic contexts, lying is often motivated by the will to avoid negative consequences (e.g., an arrest). Previous research investigating the effect of motivation on deception has, however, nearly exclusively focused on the effect of positive motivation (e.g., via financial rewards). In the current study, we aimed to replicate previous studies on the behavioral and autonomic correlates of deception and to investigate the influence of negative motivation on those correlates. Participants committed a mock theft and underwent a questioning procedure in which they had to truthfully and deceptively answer questions about the committed mock crime and a control crime. Half of the participants completed the procedure without any specific motivation, whereas the other half of the participants was told that lies detected by a computer algorithm would result in an unpleasant electric stimulation. Results revealed longer reaction times, larger skin conductance responses, and a relative heart rate slowing for lying compared to truth telling. The latter two effects were larger in the motivation compared to the control condition. Results are in line with the motivation impairment hypothesis and effects of positive motivation on the autonomic correlates of information concealment. The observation that a higher motivation increased rather than decreased deception effects is promising for forensic contexts. The possible explanation that these effects could be related to fear conditioning should stimulate future research on the stability of differences between lying and truth telling in people who experienced no or only seldom punishment for deception in their learning history.

Eye tracking as a mean to detect feigned cognitive impairment in the word memory test

Eye movements showed initial promise for the detection of deception and may be harder to consciously manipulate than conventional accuracy measures. Therefore, we integrated an eye-tracker with the Word Memory Test (WMT) and tested its usefulness for the detection of feigned cognitive impairment. As part of the study, simulators (n = 44) and honest controls (n = 41) performed WMT's immediate-recognition (IR) subtest while their eye movements were recorded. In comparison to the control group, simulators spent less time gazing at relevant stimuli, spent more time gazing at irrelevant stimuli, and had a lower saccade rate. Group classification using a scale that combined the eye movement measures and the WMT's accuracy measure showed tentative promise (i.e., it enhanced classification compared to the use of the accuracy measure as the sole predictor of group membership). Overall, integration of an eye-tracker with the WMT was found to be feasible and the eye movement measures showed initial promise for the detection of feigned cognitive impairment. Moreover, eye movement measures proved useful in enhancing our understanding of strategies utilized by the simulators and the cognitive processes that affect their behavior. While the findings are clearly preliminary, we hope that they will encourage further research of these promising psychophysiological measures.

Using more different and more familiar targets improves the detection of concealed information

When embedded among a number of plausible irrelevant options, the presentation of critical (e.g., crime-related or autobiographical) information is associated with a marked increase in response time (RT). This RT effect crucially depends on the inclusion of a target/non-target discrimination task with targets being a dedicated set of items that require a unique response (press YES; for all other items press NO). Targets may be essential because they share a feature - familiarity - with the critical items. Whereas irrelevant items have not been encountered before, critical items are known from the event or the facts of the investigation. Target items are usually learned before the test, and thereby made familiar to the participants. Hence, familiarity-based responding needs to be inhibited on the critical items and may therefore explain the RT increase on the critical items. This leads to the hypothesis that the more participants rely on familiarity, the more pronounced the RT increase on critical items may be. We explored two ways to increase familiarity-based responding: (1) Increasing the number of different target items, and (2) using familiar targets. In two web-based studies (n = 357 and n = 499), both the number of different targets and the use of familiar targets facilitated concealed information detection. The effect of the number of different targets was small yet consistent across both studies, the effect of target familiarity was large in both studies. Our results support the role of familiarity-based responding in the Concealed Information Test and point to ways on how to improve validity of the Concealed Information Test.

Validity of the Reaction Time Concealed Information Test in a Prison Sample

Detecting whether a suspect possesses incriminating (e.g., crime-related) information can provide valuable decision aids in court. To this means, the Concealed Information Test (CIT) has been developed and is currently applied on a regular basis in Japan. But whereas research has revealed a high validity of the CIT in student and normal populations, research investigating its validity in forensic samples in scarce. This applies even more to the reaction time-based CIT (RT-CIT), where no such research is available so far. The current study tested the application of the RT-CIT for an imaginary mock crime scenario both in a sample of prisoners (n = 27) and a matched control group (n = 25). Results revealed a high validity of the RT-CIT for discriminating between crime-related and crime-unrelated information, visible in medium to very high effect sizes for error rates and reaction times. Interestingly, in accordance with theories that criminal offenders may have worse response inhibition capacities and that response inhibition plays a crucial role in the RT-CIT, CIT-effects in the error rates were even elevated in the prisoners compared to the control group. No support for this hypothesis could, however, be found in reaction time CIT-effects. Also, performance in a standard Stroop task, that was conducted to measure executive functioning, did not differ between both groups and no correlation was found between Stroop task performance and performance in the RT-CIT. Despite frequently raised concerns that the RT-CIT may not be applicable in non-student and forensic populations, our results thereby do suggest that such a use may be possible and that effects seem to be quite large. Future research should build up on these findings by increasing the realism of the crime and interrogation situation and by further investigating the replicability and the theoretical substantiation of increased effects in non-student and forensic samples.

Strategic Interviewing to Detect Deception: Cues to Deception across Repeated Interviews

Previous deception research on repeated interviews found that liars are not less consistent than truth tellers, presumably because liars use a “repeat strategy” to be consistent across interviews. The goal of this study was to design an interview procedure to overcome this strategy. Innocent participants (truth tellers) and guilty participants (liars) had to convince an interviewer that they had performed several innocent activities rather than committing a mock crime. The interview focused on the innocent activities (alibi), contained specific central and peripheral questions, and was repeated after 1 week without forewarning. Cognitive load was increased by asking participants to reply quickly. The liars’ answers in replying to both central and peripheral questions were significantly less accurate, less consistent, and more evasive than the truth tellers’ answers. Logistic regression analyses yielded classification rates ranging from around 70% (with consistency as the predictor variable), 85% (with evasive answers as the predictor variable), to over 90% (with an improved measure of consistency that incorporated evasive answers as the predictor variable, as well as with response accuracy as the predictor variable). These classification rates were higher than the interviewers’ accuracy rate (54%).

Thermal signatures of voluntary deception in ecological conditions

Deception is a pervasive phenomenon that greatly influences dyadic, groupal and societal interactions. Behavioural, physiological and neural signatures of this phenomenon have imporant implications for theoretical and applied research, but, because it is difficult for a laboratory to replicate the natural context in which deception occurs, contemporary research is still struggling to find such signatures. In this study, we tracked the facial temperature of participants who decided whether or not to deceive another person, in situations where their reputation was at risk or not. We used a high-sensitivity infrared device to track temperature changes to check for unique patterns of autonomic reactivity. Using a region-of-interest based approach we found that prior to any response there was a minimal increase in periorbital temperature (which indexes sympathetic activation, together with reduced cheek temperature) for the self-gain lies in the reputation-risk condition. Crucially, we found a rise in nose temperature (which indexes parasympathetic activation) for self-gain lies in the reputation-risk condition, not only during response preparation but also after the choice was made. This finding suggests that the entire deception process may be tracked by the nose region. Furthermore, this nasal temperature modulation was negatively correlated with machiavellian traits, indicating that sympathetic/parasympathetic regulation is less important for manipulative individuals who may care less about the consequences of lie-related moral violations. Our results highlight a unique pattern of autonomic reactivity for spontaneous deception in ecological contexts.

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.