Concealed Information Test Research Articles

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.

EFFECTS OF INTELLIGENCE AND MEMORY ON NEUROPSYCHOLOGICAL RESPONSES IN POLYGRAPH TESTING

The polygraph is widely used to detect concealed information or deception; however, whether examinees’ intelligence and memory quotients would influence the psychophysiological responses, and thus the effectiveness of the polygraph, has rarely been studied systematically. The present study investigated this issue by using a polygraph on 82 participants with intelligence or memory impairments in a Concealed Information Test (CIT). The Wechsler Adult Intelligence Scale and the Wechsler Memory Scale were used to measure participants’ intelligence and memory quotients. Analysis showed that participants’ total IQ score and their scores on subtests, including information, comprehension, similarities, arithmetic, digit-symbol coding, and block design, were positively correlated with skin conductance response and the detect accuracy of the polygraph test. Participants who were tested inaccurately had significantly lower IQ scores than those who were tested accurately. In contrast, no significant correlation was found between MQ and polygraph test accuracy; however, further research is needed to investigate this issue, considering the floor effect of the Wechsler Memory Scale. The present study is not only beneficial for utilizing polygraph more scientifically, but also for expanding its application on people with cognitive impairments.

Distinguishing true from false confessions using physiological patterns of concealed information recognition – A proof of concept study

Wrongful conviction cases indicate that not all confessors are guilty. However, there is currently no validated method to assess the veracity of confessions. In this preregistered study, we evaluate whether a new application of the Concealed Information Test (CIT) is a potentially valid method to make a distinction between true and false admissions of guilt. Eighty-three participants completed problem-solving tasks, individually and in pairs. Unbeknownst to the participants, their team-member was a confederate, tempting the participant to break the experimental rules by assisting during an individual assignment. Irrespective of actual rule-breaking behavior, all participants were accused of cheating and interrogated. True confessors but not false confessors showed recognition of answers obtained by cheating in the individual task, as evidenced by larger physiological responses to the correct than to plausible but incorrect answers. These findings encourage further investigation on the use of memory detection to discriminate true from false confessions.

A Concealed Information Test System Based on Functional Brain Connectivity and Signal Entropy of Audio–Visual ERP

Deception is a human behavior and its cognitive process and mechanism involve complex neuronal activities of the brain. In this article, we develop a simple and feasible concealed information test (CIT) method which is based on the audio–visual event-related potentials (ERPs) and its spatial and temporal features. The main purpose of this article is to extend a pattern recognition method with functional network parameters and global feature entropy of the EEG signals from the whole brain. At the same time, a novel quantum neural network (QNN) classifier was developed to distinguish the guilty and innocent conditions. Functional connectivity can provide extra information of interdependence between different brain regions from the spatial dimension, and entropy can reflect the complexity of the whole brain from the temporal dimension. 20 subjects participated in the CIT experiment and 30 channel ERPs were recorded. A high accuracy of 87.67% was got in recognizing the concealed information, which was higher than 85.43% for basic features, demonstrated the effectiveness of this article. Future studies should further clarify the connectivity difference and further improve the accuracy of the QNN classifier for CIT.

Necessity of the target discrimination in the P300-based complex trial protocol test for concealed information.

The two most common types of ERP-based protocols to detect concealed information are the 3-stimulus protocol (3SP) and Complex Trial Protocol (CTP). Both protocols traditionally include presentation of a target (a stimulus with assigned significance requiring a unique behavioral response). The intention of the target presentation is forcing subjects to pay attention to all stimuli, especially to guilty knowledge stimuli, called probes. It was unclear though, how the presence of a targets influences probe recognition, and thus, the concealed information test (CIT) effect-the difference in P300 response to the probe and Irrelevant (crime-unrelated) stimuli. The question of target necessity was first raised in relation to the 3SP, and it was found that although omitting target stimuli reduced P300 amplitudes for all probe and irrelevant stimuli, the CIT effect was not reduced. The current study investigated how the presence or absence of the target/nontarget discrimination in the CTP affects the CIT effect, by comparing two CTP groups both with (T) and without (NT) the target/nontarget discrimination. The results demonstrated that this discrimination significantly increases the P300 effect. We found a greater P300 CIT effect in the T group than in the NT group, suggesting that for field use, it is better to retain the target discrimination in the CTP. CIT effects were also seen with P300 latency, but not reaction time.

Caught Virtually Lying—Crime Scenes in Virtual Reality Help to Expose Suspects’ Concealed Recognition

We explore how virtual reality could be used in police investigations to take a suspect back in time and demonstrate that they recognize a crime scene despite claiming not to. In this study, participants committed a mock crime before being incentivized to conceal recognition of crime related details (e.g., the stolen item or crime scene). The crime scenes and objects were laser scanned, converted to photo-realistic models, and presented to suspects either in virtual reality (VR) or as 2D images on a computer screen. While concealing recognition of crime information, participants’ heart rate and skin conductance were measured using a Concealed Information Test (CIT) to assess recognition. Detection of concealed recognition increased by over 25% when participants viewed crime items in VR compared to 2D images. Our findings suggest that revisiting crime scenes or objects in VR may enhance stimulus recognition and salience resulting in increased CIT diagnosticity.

A multi stage EEG data classification using k-means and feed forward neural network

ObjectiveElectroencephalography based brain-computer interface techniques are widely used these days as they bring human intentions into reality. Various researchers have proposed different approaches to decode EEG signals for applications like spellers, emotion recognition, lie detection, brain games etc. The ability to analyze concealed behavior is very important for legal and security purposes. MethodThis research aims to identify the concealed behavior of an individual. This paper presents a three-stage “Concealed Information Test” using wavelet transform, k-means clustering and multi-layer feed-forward neural network. The test has been developed by analyzing ERP component (P300) of EEG data during a mock crime scene. The wavelet transforms extracts time and frequency information from raw EEG data. K-means clustering clusters the wavelet coefficients into three clusters. As, neural network models the nonlinear time series data viz EEG, hence it has been utilized for classification of clustered data. ResultsA hybrid 3-stage classification approach is proposed by combining the advantages of all above-mentioned approaches. EEG data is recorded for a “Concealed Information Test”, for implementing the proposed framework. ConclusionThe performance of the proposed system is improved from existing approaches, by providing an accuracy of 83.1%.

The enhancing effect of incongruent verbal priming stimuli on the CIT effect with pictorial probes in the P300-based complex trial protocol

Previous research (Herring et al., 2011) indicated that certain types of incongruent verbal priming enhance responding to the subsequent (primed) stimuli. By priming participants in a P300-based Concealed Information Test (CIT), we examined the possible enhancement effects of priming stimuli in the P300 based Complex Trial Protocol (CTP) for face recognition. Participants were divided into two groups: one group with priming and one control group without. The probe (Pr) and irrelevants (Iall) of the two groups were faces, namely, pictures of the actor Tom Cruise (Pr) and of other unknown faces (Iall). One group had priming before Pr/Iall and one control group had no priming. The priming group was called the non-identical priming (NIP) group in which the verbal priming item (the name, “Bill Smith”) is identical with neither Pr nor any of the Ialls. The group without priming is the control group which is called the non-priming group (NP) that simply experiences the basic Complex Trial Protocol. Results were that non-identical priming produced larger CIT effects than the control group, which is consistent with earlier findings. Also, the amplitude of the probe of the NIP group is larger than that of the NP group, while their irrelevants didn't show any significant difference. This means that the incongruent verbal priming did enhance the P300 CIT effect for the probe, which could further improve the accuracy of CTP for the concealed information test.

Financial Incentive does not Affect P300 in the Complex Trial Protocol (CTP) Version in Concealed Information Test (CIT) in Malingering DetectionUninstructed Subjects

Introduction. Well-known research showed that the skin conductance response (SCR) of the Autonomic Nervous System (ANS) in the Concealed Information Test (CIT) is typically increased in participants who are financially and motivationally incentivized to beat the CIT (the paradoxical “motivational impairment” effect). This is not what happens with Reaction Time (RT)-based CITs, P 300 CITs based on the 3-stimulus protocol, nor on the P 300 -based complex trial protocol for detection of malingering. In the Concealed Information Test (CIT), there are at least two kinds of stimuli randomly presented regarding order to participants: The (1) probes are the items expected to be remembered; they are often from a crime scene in a forensic scenario—such as, a stolen diamond necklace. The (2) irrelevant stimuli are other comparably valuable items (a watch, a bracelet, a broach, etc.) which are from the same category as the probe (jewelry), but are not identical to it, so are unrecognized by the thief as the stolen item. The probe is recognized, and therefore elicits a larger physiological response in only the knowledgeable participant. To innocent suspects, the probe is just another irrelevant so elicits a smaller or no physiological response. Purpose. To determine how financial compensation affect P 300 in the Complex Trial Protocol (CTP) Version in Concealed Information Test (CIT) in malingering detection. Methods. P 300 measured P 300 peak to the subsequent negative peak {“peak to peak”) from Fz, Cz, and Pz, was recorded, filtered, artifacted, and averaged. Signals were passed through a Mitsar 19 channel (model 201) amplifier with a.16 Hz high pass filter setting, and low pass filters at 30 Hz. Output was conveyed to a 16-bit Mitsar Analog to Digital converter sampling at 500 Hz. For analyses and displays, single sweeps and averages were digitally filtered; the filter passed frequencies from 0 to 6 Hz using a Kaiser filtering algorithm. The present report study of motivated malingerers instructed how to beat the test, with uninstructed motivated (paid and unpaid) and unmotivated (“simple malingering”) subjects, using episodic and semantic memory probes. The Test of Memory Malingering (TOMM) validated behavioral differences among groups. Results. The present reports found the lack of financially motivated influence with both episodic and semantic memory stimuli. Also semantic memory-evoked P 300 s exceeded episodic memory evoked P 300 s. An effect of specific test-beating instructions was found to enhance the CIT effect for semantic information. Originality. The “Concealed Information Test (CIT) effect” (probe-minus-irrelevant P 300 differences) did not differ among incentive groups. Conclution. P300 amplitude is associated with the amount of focused attention to stimuli. This suggests that since a financial incentive should increase attention, the incentive manipulation should also produce larger P 300 s to familiar stimuli. However, once attention is enough to assure recognition of probes within a memory type category, the resulting P 300 s consequently generated in a more all-or-none manner are no longer influenced by motivation. Apparently, in the present study, attention to stimuli was adequate to assure recognition, whose consequent P 300 s, were no longer modifiable by motivation.

Application of Polygraph in Concealed Information Test

The polygraph-based Concealed Information Test (CIT) uses psychophysiological measures to determine whether there are crime-related information in suspects’ memory. This study explores the physiological indicators used in polygraph-based CIT and their effectiveness. Furthermore, we introduce the theoretical basis of physiological-based CIT. It is pointed out that further researches should thoroughly explore the different physiological responses and psychological process in the CIT paradigm and strengthen the comprehensive research on different psychological indicators.

Transitions of physiological changes in the concealed information test

Transitions of physiological changes in the concealed information test

Effects of concealment on physiological and psychological responses during the Concealed Information Test

Effects of concealment on physiological and psychological responses during the Concealed Information Test

Response Time Concealed Information Test on Smartphones

The Response Time-Based Concealed Information Test (RT-CIT) can reveal when a person recognizes a relevant (probe) item among other, irrelevant items, based on comparatively slower responding to the probe item. Thereby, if a person is concealing the knowledge about the relevance of this item (e.g., recognizing it as a murder weapon), this deception can be revealed. So far, the RT-CIT has been used only on desktop computers. In Experiment 1 (n = 72; within-subject), we compare the probe-irrelevant differences when using the conventional desktop-based CIT to using a smartphone-based CIT, demonstrating practical equivalence. In Experiment 2 (n = 116; within-subject), we demonstrate that using thumbs for responses (while holding the smartphone) leads to equally efficient CIT results as using conventional index finger responses. At the same time, this second experiment also demonstrates how smartphone-based studies may be efficiently run in large groups, using the participants’ own smartphones. Finally, as an interesting addition, here for the first time we also measured keypress durations (i.e., the time durations of holding down the response keys) in the RT-CIT, which we found to be significantly shorter for probe than for irrelevant items.

The Accuracy of Permutation Test in P300-based Concealed Information Test

The Accuracy of Permutation Test in P300-based Concealed Information Test

The effect of retroactive memory interference on the P300-based Complex Trial Protocol (CTP)

In a P300-based concealed information test (CIT), an increased response to a crime-related “probe” item of interest suggests concealed knowledge. Because the CIT's detection ability is based on knowledgeable parties recognizing the key item, weakening the crime memory might decrease probe identifiability and reduce diagnostic power. Research on retroactive memory interference (RI) has shown that acquiring new information after encoding a memory can degrade the original memory, which suggests that RI might pose a threat to CITs. To test this, Gronau et al. (2015) had participants complete a mock-crime, followed by either a control task or a RI manipulation task, intended to impair the crime memory. Both the simple guilty control and RI groups were subdivided into three time delay conditions: 1/3 of participants immediately completed the task and CIT, another 1/3 completed the task and returned a week later for the CIT, and the remaining participants completed both the task and CIT a week later. Results showed that RI reduced memory of crime details and skin conductance responses, while respiration line length was unaffected. Here, we extend Gronau et al. (2015), using the Complex Trial Protocol (CTP) version of the P300-based CIT, to investigate the influence of RI on recognition. The CIT effect was obvious in all six group × time delay subconditions, as evidenced by their significantly larger probe vs. irrelevant amplitudes, high percentage of bootstrapped iterations where probe > irrelevants, bootstrapped mean amplitude differences, and satisfactory hit rates. However, these indices of the CIT effect did not differ based on group or time delay, as was the case for target response error rates and P300 latencies. The only outcome of interest to vary by group or time delay was behavioral response times: both probe and combined irrelevant responses were delayed in the control (simple guilty) group. Thus, the evidence suggests that the RI manipulation used here does not threaten the P300-based CTP's accuracy. Results are considered as they compare to previous work, and limitations and possible explanations for our results are discussed.

Individual differences in ERPs during deception: Observing vs. demonstrating behavior leading to a small social conflict

The present study investigated individual differences modulating P300 and MFN amplitudes in a concealed information test (CIT). Some participants were offered candy and either denied (n = 41) or ate it (n = 31), while others witnessed an examiner eating it (informed condition; n = 34). Afterwards it was suggested that the candy was not meant for them. During the CIT, participants saw the candy (probe) and similar unknown items (irrelevants) and indicated that they did not know them. P300 and MFN amplitudes differed for probe and irrelevant items, revealing that known items were more salient and deception was accompanied by response conflicts. Larger differences between P300s for probe versus irrelevant items occurred for women. Furthermore, especially for women, response conflicts diminished when being in the informed condition. Different patterns of MFN amplitudes appeared for informed women depending on the Machiavellianism score, suggesting that gender and Machiavellianism could be related to different cognitive processing during deception.

Lie detection using extreme learning machine: A concealed information test based on short‐time Fourier transform and binary bat optimization using a novel fitness function

AbstractLie detection is one of the major challenges that is being faced by the forensic sciences. Identification of lie on the basis of a person's mental behavior is a tedious task. Brain‐computer interface is one such medium which provides a solution to this problem by displaying visual stimuli and recording subject's brain responses. A P300 response is elicited whenever a person comes across a familiar stimuli in a series of rare stimuli. This P300 response is used for the lie detection method. In the proposed concealed information test, acquired signals are preprocessed to discard noise. Then, short‐time Fourier transform method is applied to extract features from the preprocessed electroencephalogram signals. To avoid the curse of dimensionality and to reduce computational overhead, binary bat algorithm is applied, which helps in choosing optimal subset of features. The obtained set of features is given as an input to the extreme learning machine classifier for training of guilty and innocent samples. The performance of the system is assessed using 10‐fold cross‐validation. The resultant accuracy obtained from the proposed lie detection system is 88.3%. The system has provided efficient results in contrast with most of the state‐of‐the‐art lie detection methods.

Development of time interval-sliding method applicable to respiratory measures used in concealed information tests

A time interval-sliding (TIS) method was developed for analysis of respiratory measures such as respiratory line length (RLL) and weighted average (WA) that are used in concealed information tests (CIT). The validity of this method was tested using simulations. The TIS method shifts the time interval such that its starting point for an analysis shifts to the bottom of the respiratory cycle. In study 1, it was demonstrated that negative influences on RLL and WA caused by a starting point of analysis could be solved using the TIS method. In study 2, the efficacy of the TIS method was tested using CIT simulations. The results of these two studies indicated that the TIS method improves discriminability of RLL and WA. It was also found that the discriminability of the RLL was improved to the same level as those of the WA, although the RLL values were lower than those of the WA prior to operating the TIS method. Therefore, it can be expected that the TIS method will be an effective technique for the analysis of respiratory measures of CIT.

A Synergistic Concealed Information Test With Novel Approach for EEG Channel Selection and SVM Parameter Optimization

In the era of data, it is a challenging task to classify continuous data such as electroencephalographic data. The electroencephalographic signal maps several thoughts going in an individual’s brain by connecting a device to the human brain. In this paper, we have proposed a deceit identification system using a test called “concealed information test.” The electroencephalographic data have been recorded when the concealed information test is performed for experimental analysis. To enhance the performance of the deceit identification system, the optimization of support vector machine (SVM) parameters and the selection of the EEG channels are performed. This paper implements a binary version of the BAT algorithm (binary BAT algorithm) and the conventional BAT algorithm on the electroencephalography (EEG) data. A novel cost function is also proposed, which utilizes the results of continuous BAT and binary BAT to enhance the system performance. In this synergistic approach, BAT is used for the SVM parameters optimization, and the binary BAT algorithm is applied for the EEG channel selection. The performance of the system is improved, and it is inferred that the channels placed at the occipital lobe of the brain consist of the artifacts. After removing the channels placed on the occipital lobe, i.e., O1, Oz, and O2, and using the optimized SVM parameters, the system’s average accuracy increases from 94.11% to 96.8%.

Evaluative Observation in a Concealed Information Test.

The Concealed Information Test (CIT) is a valid method to detect hidden knowledge by means of psychophysiological measures. Concealing information is always a social behavior; yet, the role of social aspects has barely been investigated in recent CIT research favoring standardized, computer-based experiments. Evaluative observation is known to influence social behavior as well as physiological measures; examining the impact of evaluative observation on physiological responding in a CIT is the aim of this study. Sixty-three students completed a mock-crime and then underwent a CIT. In a between-subjects manipulation, half of the participants were observed through a camera and were faced with the real-time video of the experimenter watching them while completing the CIT. The other half completed the CIT without observation and video. Electrodermal activity, respiration line length, phasic heart rate, and finger pulse waveform length were registered. A specific questionnaire captured the individual fear of negative evaluation. Typical differential CIT responses occurred in both groups and with each measure. Contrary to expectations, differential CIT responses did not differ between groups. No modulatory influence of the fear questionnaire score on physiological responding was found. A ceiling effect, involving high attention and high motivation to avoid detection as well as high arousal in both groups due to the CIT procedure per se is discussed as explanation for these results, while the independence of the orienting reflex of social and motivational influence appears less likely in the light of previous literature.