The objective use of multiple physiological indices in the detection of deception

The role of response conflict in concealed information detection with reaction times

The concealed information test (CIT) presents various probe (familiar) items amidst irrelevant (unfamiliar) items. When the probe items appear, reaction time (RT) slows down. This RT-CIT effect has been accounted for by a conflict resulting from the need to deny familiarity of the familiar probes. The present pre-registered study (n = 292) examined whether response conflict is sufficient to account for the RT-CIT effect, using city and name items. Specifically, we compared the common conflict condition, where the response buttons emphasized familiarity of CIT items ("unfamiliar" versus "familiar"), to a novel no conflict condition, where the buttons emphasized categorical membership ("city" versus "name"). In line with our expectations, the RT-CIT effect was substantially stronger in the conflict condition; yet, it remained significant even in the no conflict condition. This implies a critical role for response conflict, but also suggests that other mechanisms (e.g. orientation to significant stimuli) may contribute to the RT-CIT effect.

Did You Just Lie to Me? Deception Detection in Face to Face versus Computer Mediated Communication

Individuals' deception detection ability during either a face-to-face (FtF) interaction or through computer-mediated communication (CMC) was explored under more naturalistic conditions where they were not forewarned that deception may be involved. Participants discussed a social issue either in a room together or by instant messaging from separate rooms. Prior to discussion, some participants were asked to deceive their partner regarding their actual opinion on the issue. Results showed that mode of communication did not influence participants' deception detection accuracy rate, nor their truth bias. Regardless of mode of communication, deceptive participants experienced the same level of physiological arousal as the non-deceivers. In contrast, deceivers reported experiencing higher levels of anxiety but only in the FtF condition. Findings highlight how for different communication modalities, a multitude of interactive factors may influence deception detection.

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.

Deception Detection by Hybrid-Pair Wireless fNIRS System

Normal fNIRS setting up was limited by superficial physiological noises when applied into the deception detection. We designed a hybrid-pair wireless fNIRS system to improve the detection. The system takes advantages of short-pair channel to suppress the effect of physiological noises, and wireless module to improve the comfortableness of wearing it. We applied the system into a modified Guilty Knowledge Test. The experiment demonstrated that normal metrics might hint different energy consume during lying, while the regional oxygen saturation rSO2, specific in the system, is sensitive to indicate a lying.

Diagnosing Estimate Distortion Due to Significance Testing in Literature on Detection of Deception

Studies journals typically report or feature results significant by statistical test criterion. This is a bias that prevents obtaining precise estimates of the magnitude of any underlying effect. It is severe with small effect sizes and small numbers of measurements. To illustrate the problem and a diagnosis technique, results of published studies on the detection of deception are graphed. The literature contains large effect sizes affirming that deceptive responses in contrast to truthful responses are associated with more reactive Skin Resistance Responses. These effect sizes when graphed on the x-axis against n on the y-axis are distributed as funnel graphs. A subset of studies show support for predicted small to medium effects on different physiological measures, individual differences, and condition manipulations. These effect sizes graphed by sample ns follow negative correlations, suggesting that effect sizes from published values of t, F, and z are exaggerations.

Detecting false intent using eye blink measures

Eye blink measures have been shown to be diagnostic in detecting deception regarding past acts. Here we examined—across two experiments with increasing degrees of ecological validity—whether changes in eye blinking can be used to determine false intent regarding future actions. In both experiments, half of the participants engaged in a mock crime and then transported an explosive device with the intent of delivering it to a “contact” that would use it to cause a disturbance. Eye blinking was measured for all participants when presented with three types of questions: relevant to intent to transport an explosive device, relevant to intent to engage in an unrelated illegal act, and neutral questions. Experiment 1 involved standing participants watching a video interviewer with audio presented ambiently. Experiment 2 involved standing participants questioned by a live interviewer. Across both experiments, changes in blink count during and immediately following individual questions, total number of blinks, and maximum blink time length differentiated those with false intent from truthful intent participants. In response to questions relevant to intent to deliver an explosive device vs. questions relevant to intent to deliver illegal drugs, those with false intent showed a suppression of blinking during the questions when compared to the 10 s period after the end of the questions, a lower number of blinks, and shorter maximum blink duration. The results are discussed in relation to detecting deception about past activities as well as to the similarities and differences to detecting false intent as described by prospective memory and arousal.

[Non-contact measurement of eye movements in the detection of deception]

The effectiveness of detecting deception by measuring eye movements without making contact was investigated. A deception-detection protocol was used with two conditions based on the stimulus similarity to the critical image. Volunteer participants (N = 63) were randomly assigned to either the high or the low-similarity condition. They were randomly presented with critical and non-critical images and their eye movements were measured without contact. High-similarity images were presented in the high-similarity condition and low-similarity images were presented in the low-similarity condition. The results showed no significant differences in eye movements between the critical and non-critical images in the high-similarity condition. In contrast, in the low-similarity condition, the frequency and total length of time for glancing at critical images were significantly lower than for glancing at non-critical images. These results are suggestive of the effectiveness of the non-contact measurement of eye movements for the detection of deception.

Combining blink, pupil, and response time measures in a concealed knowledge test

The response time (RT) based Concealed Knowledge Test (CKT) has been shown to accurately detect participants' knowledge of mock-crime-related information. Tests based on ocular measures such as pupil-size and blink-rate have sometimes resulted in poor classification, or lacked detailed classification analyses. The present study examines the fitness of multiple pupil and blink related responses in the CKT paradigm. To maximize classification efficiency, participants' concealed knowledge was assessed using both individual test measures and combinations of test measures. Results show that individual pupil-size, pupil-slope, and pre-response blink-rate measures produce efficient classifications. Combining pupil and blink measures yielded more accuracy classifications than individual ocular measures. Although RT-based tests proved efficient, combining RT with ocular measures had little incremental benefit. It is argued that covertly assessing ocular measures during RT-based tests may guard against effective countermeasure use in applied settings. A compound classification procedure was used to categorize individual participants and yielded high hit rates and low false-alarm rates without the need for adjustments between test paradigms and subject populations. We conclude that with appropriate test paradigms and classification analyses, ocular measures may prove as effective as other indices, though additional research is needed.

Current research and potential applications of the concealed information test: an overview

Research interest in psychophysiological detection of deception has significantly increased since the September 11 terror attack in the USA. In particular, the concealed information test (CIT), designed to detect memory traces that can connect suspects to a certain crime, has been extensively studied. In this paper I will briefly review several psychophysiological detection paradigms that have been studied, with a focus on the CIT. The theoretical background of the CIT, its strength and weaknesses, its potential applications as well as research finings related to its validity (based on a recent meta-analytic study), will be discussed. Several novel research directions, with a focus on factors that may affect CIT detection in realistic settings (e.g., memory for crime details; the effect of emotional stress during crime execution) will be described. Additionally, research focusing on mal-intentions and attempts to detect terror networks using information gathered from groups of suspects using both the standard CIT and the searching CIT will be reviewed. Finally, implications of current research to the actual application of the CIT will be discussed and several recommendations that can enhance the use of the CIT will be made.

The contributions of prefrontal cortex and executive control to deception: evidence from activation likelihood estimate meta-analyses

Previous neuroimaging studies have implicated the prefrontal cortex (PFC) and nearby brain regions in deception. This is consistent with the hypothesis that lying involves the executive control system. To date, the nature of the contribution of different aspects of executive control to deception, however, remains unclear. In the present study, we utilized an activation likelihood estimate (ALE) method of meta-analysis to quantitatively identify brain regions that are consistently more active for deceptive responses relative to truthful responses across past studies. We then contrasted the results with additional ALE maps generated for 3 different aspects of executive control: working memory, inhibitory control, and task switching. Deception-related regions in dorsolateral PFC and posterior parietal cortex were selectively associated with working memory. Additional deception regions in ventrolateral PFC, anterior insula, and anterior cingulate cortex were associated with multiple aspects of executive control. In contrast, deception-related regions in bilateral inferior parietal lobule were not associated with any of the 3 executive control constructs. Our findings support the notion that executive control processes, particularly working memory, and their associated neural substrates play an integral role in deception. This work provides a foundation for future research on the neurocognitive basis of deception.

Behavioral and Physiological Measures in the Detection of Concealed Information

The authors examined the incremental validity of the reaction time (RT) measure beyond that of skin conductance response (SCR) in the detection of concealed information. Participants performed a Stroop-like task in which they named the color of critical and neutral words. Results show that the SCR highly differentiated between the relevant and neutral words. However, the RT demonstrated a significant differentiation only when the critical words denoted personally significant items (e.g., one's own name) and not when they denoted crime-relevant items related to a simulated crime. In both cases, combining the 2 measures yielded no advantage over the use of SCR alone. Thus, although behavioral measures may differentiate between relevant and neutral information in some cases, their practical use is questionable.

Comparison of Polygraph Data Obtained From Individuals Involved in Mock Crimes and Actual Criminal Investigations

In a preliminary attempt to determine the generalizability of data from laboratory mock-crime studies, the authors examined the similarities and differences among the cardiovascular, electrodermal, and respiration responses of deceptive and nondeceptive individuals elicited to crime-relevant and crime-irrelevant questions. Participants in the laboratory group were randomly assigned to nondeceptive (n = 28) or deceptive (n = 27) treatment groups, and a mock-crime scenario was used. The field participants were confirmed nondeceptive (n = 28) or deceptive (n = 39) criminal suspects who underwent polygraph examinations between 1993 and 1997. The results indicated that there were salient differences between field and similarly obtained laboratory polygraph response measures. However, accuracy of laboratory participants' classifications using logistic regression analysis was not significantly different from field participants' classification accuracy.

The validity of psychophysiological detection of information with the Guilty Knowledge Test: a meta-analytic review

The authors performed a meta-analysis based on 169 conditions, gathered from 80 laboratory studies, to estimate the validity of the Guilty Knowledge Test (GKT) with the electrodermal measure. The overall average effect size was 1.55, but there were considerable variations among studies. In particular, mock-crime studies produced the highest average effect size (2.09). Three additional moderators were identified: Motivational instructions, deceptive ("no") verbal responses, and the use of at least 5 questions were associated with enhanced validity. Finally, a set of 10 studies that best approximated applications of the GKT under optimal conditions produced an average effect size of 3.12. The authors discuss factors that might limit the generalizability of these results and recommend further research of the GKT in realistic setups.

Cues to deception

Do people behave differently when they are lying compared with when they are telling the truth? The combined results of 1,338 estimates of 158 cues to deception are reported. Results show that in some ways, liars are less forthcoming than truth tellers, and they tell less compelling tales. They also make a more negative impression and are more tense. Their stories include fewer ordinary imperfections and unusual contents. However, many behaviors showed no discernible links, or only weak links, to deceit. Cues to deception were more pronounced when people were motivated to succeed, especially when the motivations were identity relevant rather than monetary or material. Cues to deception were also stronger when lies were about transgressions.

Eye blinks: new indices for the detection of deception

Eyeblink variables were investigated while subjects performed a guilty knowledge test (Experiment 1) and a dual modality attention task (Experiment 2). In both experiments, the temporal distribution of blinks was analyzed using an automatic video based blink analysis system [Matsuo and Fukuda, Jpn. J. Physiol. Psychol. Psychophysiol., 14 (1996), 17]. In experiment 1, the blink rate pattern discriminated between relevant and irrelevant stimuli. In experiment 2, the blink rate peak after the auditory stimulus disappeared during visually attended tasks whereas the blink rate peak after the visual stimulus was significant during auditory attended tasks. It was suggested that eye blinks could be related to the selective attention and that eye blinks could provide an additional index for the detection of deception.

Effect of acupuncture stimulation of the auricular sympathetic point on evoked sudomotor response

OBJECTIVES

To investigate whether stimulation of the auricular sympathetic acupuncture point would affect the mean maximum amplitude of evoked sudomotor responses.

DESIGN

A placebo-controlled trial. Two types of controls were used: no acupuncture and acupuncture of an alternate "non-sympathetic nervous system" related (i.e., a non-sympathetic, placebo) point. Subjects were included in either the placebo or the test group. Each subject would have one session of acupuncture and one session without acupuncture, the acupuncture was applied in either the first or the second session. Initially, each group was unaware in which of the two sessions they would receive acupuncture (cross-over design). Each individual was unaware of which group they were to participate in.

SETTINGS/LOCATION

A quiet, sealed room with a constant temperature, in the research department of the Anglo-European College of Chiropractic.

SUBJECTS

Thirty-eight asymptomatic male, white volunteers (18 to 40 years old).

INTERVENTIONS

The two groups underwent two electrodermal response (EDR) recording sessions, at an interval of 5 weeks. During each session, they were also presented with eight stimuli, each of which was designed to stimulate the sympathetic nervous system. In each session, subjects either received auricular acupuncture (AA) or did not.

OUTCOME MEASURES

The maximum amplitude of the EDR for each stimulus.

RESULTS

AA at the non-sympathetic, placebo point significantly increased EDR both with respect to the individual stimuli (p < or = 0.05 to < or = 0.001) and for the pooled data (p = 0.0001). AA to the sympathetic point produced no significant change in EDR for either individual stimuli (p range > or = 0.8 to > or = 0.1) or for the pooled data (p > 0.8). A significant difference was found between the results from placebo and sympathetic point stimulated groups during AA for 2 of the 8 stimuli (p < 0.05), and for the pooled data from all 8 stimuli (p = 0.0006).

CONCLUSION

Stimulation of the sympathetic AA point significantly decreased the stimulus-evoked EDR when compared with an AA stimulation to a non-sympathetic (placebo) point. However, it did not significantly alter EDR compared with no treatment. This implies that the increase in response as a result of inserting the needles was negated by placing the electrodes in the AA sympathetic point. Consequently, one might surmise that there may be a specific action of AA in respect to hyperhidrosis resulting from an increase in sympathetic activity.

Effects of item repetitions and variations on the efficiency of the guilty knowledge test

Two mock-crime experiments were designed to examine the effects of question repetition and variation on the efficiency of the guilty knowledge test. In the first experiment, two factors (single vs. multiple questions, and high vs. low motivation) were manipulated and in the second experiment, which was an analog study conducted in a police laboratory using field equipment, only the first factor was examined. Similar detection efficiencies were obtained in both experiments when a single question was repeated 12 times, and when each of four different questions was repeated 3 times. The results also showed that accumulating information across repetitions and across physiological measures tended to increase detection efficiency and reduce false positive errors. The results of Experiment 1 suggest that motivation to avoid detection may be associated with better detection efficiency.

The accuracy of human decisions and objective measurements in psychophysiological detection of knowledge

I examined the relative detection efficiency of three measurements--skin resistance response (SRR) amplitude, respiration line length (RLL), and human respiration response evaluation (RRE)--in a guilty knowledge experiment. Thirty-two subjects were presented with lists of personal information in which only one of five items was correct. Subjects were instructed to try to avoid detection of the relevant items in the polygraph test. All three measurements discriminated better than chance between relevant and neutral items, with the objectively measured SRR and RLL superior to the subjective RRE. When SRR and RLL were compared for their relative efficiency, the former yielded better detection. The differentiation was even better with a measure that combined the SRR and the RLL. The results are discussed with respect to previous findings and practical implications.

Clinical judgment and decision-making in CQT-polygraphy. A comparison with other pseudoscientific applications in psychology

The control questions technique (CQT) is the most widely used method of psychophysiological detection, in spite of its questionable scientific status and the lack of sufficient empirical basis. The goal of this paper is to account for the tremendous popularity of the CQT, and to present a theory describing how decisions and conclusions are reached within the typical CQT-interrogation process. It is claimed that the examiner starts with an a priori hypothesis derived from background information and from prior interactions with the examinee. The test-specific information is then used to test the a priori hypothesis, but this process is influenced by the confirmation bias. The complexity of the information available to the examiner coupled with the lack of well-defined quantification and integration rules allow the examiner to overweigh confirming evidence and to disregard disconfirming cues. This description may be applicable to several other pseudoscientific methods. The implications of the present theory for CQT polygraphy are discussed and comparisons with other purported applications of psychology are made.

Meprobamate reduces accuracy of physiological detection of deception

Normal male subjects attempted to deceive an experimenter recording electrodermal, respiratory, an cardiovascular activity. Those who had ingested a placebo or nothing were detected with statistically significant frequency on the basis of their phasic electrodermal responses, which clearly distinguished them from truthful suspects. That was not the case with deceptive subjects who had ingested 400 milligrams of meprobamate, nor did the examiner detect which subjects had received the drug.