Concealed Information Test Research Articles

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.

Examining levels of processing using verbal & pictorial stimuli with the complex trial protocol in a mock theft scenario

The Complex Trial Protocol (CTP) is an EEG-based Concealed Information Test (CIT). Depth of processing influences memorability where deeper processing increases recollection. The CTP’s performance as a function of shallow versus deep levels of processing has not been explored. Two experiments were conducted, one with verbal stimuli and the other with their pictorial referents. In both experiments, participants were randomly assigned to three groups, Innocent Control (Control) condition, Guilty Immediate Shallow Processing (Shallow) condition, and Guilty Immediate Deep Processing (Deep) condition. Shallow and Deep participants from both experiments underwent the same mock theft scenario and all three groups were later exposed to either a verbal (N = 41) or pictorial (N = 43) stimulus on a computer monitor. In the word study, no differences in CIT effect were found between any of the groups. Areas under the curve (AUCs) did not differ from chance (.624 and .679 for Shallow and Deep groups respectively). In the image study, the CIT effect for the Shallow and Deep groups differed from the Control one. The AUCs (.755 and .943 for the Shallow and Deep groups respectively) differed significantly from each other. Levels of Processing (LOP) did not appear to have any bearing on CTP performance when words were used as probes but did have an effect when images were used. The findings may hint at some of the limitations of the CTP and fail to replicate similar experiments, especially when words are used as probes, from the late Peter Rosenfeld’s laboratory.

Diagnosing eyewitness identifications with reaction time‑based Concealed Information Test: the effect of viewpoint congruency between test and encoding

Mistaken eyewitness identifications continue to be a major contributor to miscarriages of justice. Previous experiments have suggested that implicit identification procedures such as the Concealed Information Test (CIT) might be a promising alternative to classic lineups when encoding conditions during the crime were favorable. We tested this idea by manipulating view congruency (frontal vs. profile view) between encoding and test. Participants witnessed a videotaped mock theft that showed the thief and victim almost exclusively from frontal or profile view. At test, viewing angle was either congruent or incongruent with the view during encoding. We tested eyewitness identification with the RT-CIT (N = 74), and with a traditional simultaneous photo lineup (N = 97). The CIT showed strong capacity to diagnose face recognition (d = 0.91 [0.64; 1.18]), but unexpectedly, view congruency did not moderate this effect. View congruency moderated lineup performance for one of the two lineups. Following these unexpected findings, we conducted a replication with a stronger congruency manipulation and larger sample size. CIT (N = 156) showed moderate capacity to diagnose face recognition (d = 0.63 [0.46; 0.80]) and now view congruency did moderate the CIT effect. For lineups (N = 156), view congruency again moderated performance for one of the two lineups. Capacity for diagnosing face recognition was similar for lineups and RT-CIT in our first comparison, but much stronger for lineups in our second comparison. Future experiments might investigate more conditions that affect performance in lineups vs. the RT-CIT differentially.

Guilty on the Go: Uncovering Concealed Information by Assessing Response Preparation Processes in a Go-Nogo-Paradigm

The Reaction Time-Based Concealed Information Test (RT-CIT) was designed to detect familiarity with crime-related information. However, RT-CIT results can be manipulated by preparing innocent-looking responses for these probes. We developed a new paradigm allowing us to assess such response preparation processes. In each trial of the task, a crime-related prime question was presented, followed by a test item which was either a publicly known item, an irrelevant item, or a probe. The test item could either match the question in terms of content or not, and a key had to be pressed if the answer was not publicly known (Go-Nogo task). In two experiments (total N = 138), we found evidence for both familiarity (slower reactions toward crime-related than unrelated information) and response preparation effects (less errors for probes matching the prime question) in guilty participants, indicating that the new paradigm can help to overcome problems of strategic response preparation.

Reliability of the P3 component in a 3-stimulus concealed information test with known and unknown stimuli

The parietal P3 amplitude of the event-related potential (ERP) has been highlighted to signal stimulus salience in concealed information tests (CITs) with known and unknown stimuli. To extend previous validity investigations in deception research, the reliability of the early parietal P3 amplitude in a 3-stimulus CIT including known and unknown stimuli has been investigated in a sample of N = 68 participants. Variations of Cronbach’s Alpha and split-half reliability (odd–even, 1st vs. 2nd half) of the early parietal P3 amplitude were considered for ERP quantification method (peak-to-peak, mean, baseline-to-peak), epoch selection strategies (chronological vs. random) and number of epochs (10–40) in three stimulus types (probe, target, irrelevant). Excellent reliability coefficients have been summarized for number of epochs, P3 quantifications, and epoch selection strategies. Moreover, the best-practice recommendations highlight mandatory combinations of epoch selection strategy, number of epochs and P3 quantifications to ensure robust and excellent reliabilities of the early parietal P3 amplitude in a 3-stimulus CIT with known (probe, target) and unknown (irrelevant) stimuli. The robustness of mandatory excellent reliability coefficients for the early parietal P3 has been discussed for two data tracks in single-case analyses.

Response time concealed information test using fillers in cybercrime and concealed identity scenarios

ABSTRACT The Response Time Concealed Information Test (RT-CIT) can reveal that a person recognises a relevant item (e.g., a murder weapon) among other control items, based on slower responses to the former compared to the latter ones. To date, the RT-CIT has been predominantly examined only in the context of scenarios that are very unlikely in real life, while sporadic assessment has shown that it suffers from low diagnostic accuracy in more realistic scenarios. In our study, we validated the RT-CIT in the new, realistic, and very topical mock scenario of a cybercrime (Study 1, n = 614; Study 2; n = 553), finding significant though moderate effects. At the same time (and expanded with a concealed identity scenario; Study 3, n = 250), we assessed the validity and generalizability of the filler items presented in the RT-CIT: We found similar diagnostic accuracies when using specific, generic, and even nonverbal items. However, the relatively low diagnostic accuracy in case of the cybercrime scenario reemphasizes the importance of assessments in realistic scenarios as well as the need for further improving the RT-CIT.

Interactive slide selection algorithm and machine learning in psychophysiological memory testing

Objective. To present a new type of concealed information test (CIT) that implements the interactive slide selection (ISS) algorithm and compare its effectiveness with a standard CIT (sCIT). Approach. The ISS algorithm presents slides interactively, based on the analysis of electrodermal activity, while sCIT presents slides in a predefined, sequential order. The algorithm automatically selects irrelevant, relevant, and control slides and presents them at the moment which is physiologically most suitable for electrodermal response detection. To compare the ISS-based CIT (issCIT) and sCIT, two objects, a bag, and a wallet, were presented to 64 participants, 32 of whomwere analyzed with sCIT, and another 32 with issCIT. Main results. The results show that ISS had significantly better true/false predictions (Fisher’s exact test, p < 0.01). Also, the number of false positives (FPs) was significantly lower in the issCIT group in comparison with sCIT (Fisher’s exact test, p < 0.001). Machine learning (ML) classifiers improved precision from 49% to 79% in the sCIT group (McNemar’s test, p < 0.05), and from 85% to 100% in the issCIT group (McNemar’s test, p < 0.05). The testing time in the issCIT group ranged between 42 and 107 s, while the average was 53 s. In the sCIT group, the testing time was always 330 s. Significance. Under the presented experimental settings, the ISS algorithm obtained significantly better classification results compared to sCIT, while the application of the ML algorithms managed to improve the classification results in both groups reaching a precision of 100%. The ISS algorithm allowed for a much shorter testing time compared to sCIT.

Assessing partial errors via analog gaming keyboards in response conflict tasks: A proof-of-concept study with the concealed information test.

The response time-based Concealed Information Test (RT-CIT) is an established memory detection paradigm. Slower RTs to critical information (called 'probes') compared to control items (called 'irrelevants') reveal recognition. Different lines of research indicate that response conflict is a strong contributor to this RT difference. Previous studies used electromyography (EMG) to measure response conflict, but this requires special equipment and trained examiners. The aim of this study was to explore if response conflict can also be measured with an analog gaming keyboard that is sensitive to minimal finger movements. In a preregistered study, participants completed an autobiographical RT-CIT (n = 35) as well as a cued recognition task (modified Sternberg task; n = 33) for validation purposes. Partial errors, partial button presses of the incorrect response key, were more frequent in trials with response conflict than in trials without conflict. Partial errors were rare (CIT: 2.9%; Sternberg: 1.7% of conflict trials), suggesting analogue keyboards have lower sensitivity than EMG. This is the first evidence that analog keyboards can measure partial errors. Although likely less sensitive than EMG measures, potential benefits of analog keyboards include their accessibility, their compatibility with all tasks that use a standard keyboard, that no physical contact with the participant is needed, and ease of data collection (e.g., allowing for group testing).

The Challenge to distinguish differences among encoding methods in the concealed information test An examination to distinguish encoding methods within participants

The Challenge to distinguish differences among encoding methods in the concealed information test An examination to distinguish encoding methods within participants

Selective memory detection: Context-dependent stimulus significance in the concealed information test

Previous studies have posited that the significance of a crime-relevant item in a question produces differential physiological responses in the Concealed Information Test (CIT). However, this term is equivocal and needs to be clarified in order to strengthen the theoretical underpinnings of the CIT. The present study examined the hypothesis that differential responding depends on the examinee’s understanding of which item in a question is relevant to a given context. Participants performed a mock theft task, in which they were instructed to steal one item from each of two different locations. An identical CIT question asking about each stolen item was presented under different location contexts while skin conductance response, heart rate, and respiratory activity were recorded. Results indicated that only the relevant item specified by the context of the instruction elicited reliable differential physiological responses. This finding implies that differential responding in the CIT is flexible and context-dependent, and that specifying the subject of a given question is important for detecting crime-relevant memories in practical criminal investigations.

Orienting versus inhibition: The theory behind the ocular-based Concealed Information Test.

When trying to conceal one's knowledge, various ocular changes occur. However, which cognitive mechanisms drive these changes? Do orienting or inhibition-two processes previously associated with autonomic changes-play a role? To answer this question, we used a Concealed Information Test (CIT) in which participants were either motivated to conceal (orienting + inhibition) or reveal (orienting only) their knowledge. While pupil size increased in both motivational conditions, the fixation and blink CIT effects were confined to the conceal condition. These results were mirrored in autonomic changes, with skin conductance increasing in both conditions while heart rate decreased solely under motivation to conceal. Thus, different cognitive mechanisms seem to drive ocular responses. Pupil size appears to be linked to the orienting of attention (akin to skin conductance changes), while fixations and blinks rather seem to reflect arousal inhibition (comparable to heart rate changes). This knowledge strengthens CIT theory and illuminates the relationship between ocular and autonomic activity.

A new theoretical perspective on concealed information detection.

The concealed information test (CIT) was designed to detect concealed knowledge. It does so by measuring differential physiological and behavioral responses to concealed, compared to control, items - i.e., the CIT effect. Although the CIT has gained extensive empirical support in laboratory studies, scientific validity requires also a theoretical understanding of the method's underlying mechanisms. In this article, we present a new theoretical perspective. Specifically, we elaborate and clarify several features of Orienting Response (OR) theory, which has been the dominant theory in this domain. Importantly, we suggest for the first time that the voluntary (rather than the involuntary) OR modulates the CIT effect. Second, we argue that motivational-emotional accounts of the CIT effect are consistent with OR theory and cannot be considered as alternative approaches. Finally, we discuss some more recent developments which highlight the idea that different physiological measures reflect different underlying mechanisms - an idea dubbed as response fractionation.

Belief or disbelief in feedback influences the detection efficiency of the feedback concealed information test.

The feedback concealed information test (fCIT) is a new variant of the CIT that added feedback about participants’ concealing performances in the classical CIT. The advantage of the fCIT is that the resulting feedback related event-related potentials (ERPs) can be used to detect concealed information. However, the detection efficiency of feedback-based ERPs varies across studies. The present experiment examined whether the extent participants believed the feedback influenced their detection efficiency. Specifically, participants did a mock crime and were then tested in a fCIT. Following the fCIT, participants were asked to report how much they believed the feedback was accurate. Results showed that there were no significant correlations between the amplitude of the feedback related negativity (FRN), feedback P300, and participants’ self-report at the group level. However, individual analyses showed that the detection efficiency of both the FRN and feedback P300 were influenced by participants’ belief about the presented feedback. The detection efficiency of the FRN and the feedback P300 was higher among participants who believed the feedback. These findings suggest that the fCIT is dependent to some extent on the participants’ level of belief in the feedback.

How to Detect Concealed Crime Knowledge in Situations With Little Information Using the Forced Choice Test

The Forced Choice Test (FCT) can be used to detect concealed crime knowledge, but it requires more evidence than typically available from a crime to be constructed. We propose a method to repeat individual pieces of evidence to achieve the necessary test length, hence widening the practical applicability. According to our method, FCT trials are created so that on each trial examinees are presented with a novel and unique decision between two answer alternatives even if a specific piece of information is presented again. We argue that if the decision in each trial is unique, the properties and diagnosticity of a traditional FCT can be maintained. In experiment 1, we provide a proof of concept by comparing our novel method with a traditional FCT and demonstrate that an FCT with repeated presentation of the same evidence has diagnostic value (AUC = .69) albeit less so than a traditional FCT (AUC = .86). In experiment 2, we put our novel FCT to the test in a situation with insufficient information for a traditional FCT alongside the Concealed Information Test (CIT), which also detects concealed information but relies on psychophysiological indices. Both, the FCT (AUC = .81) and CIT (AUC = .83) were diagnostic and combining them increased the detection accuracy even further (AUC = .91). If replicated, our novel FCT increase practical applicability of the FCT in general and in conjunction with the CIT.

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.

Brain fingerprinting field study on major, terrorist crimes supports the brain fingerprinting scientific standards hypothesis: classification concealed information test with P300 and P300-MERMER succeeds; comparison CIT fails.

The online version contains supplementary material available at 10.1007/s11571-022-09795-1.

Machine Learning Mega-Analysis Applied to the Response Time Concealed Information Test: No Evidence for Advantage of Model-Based Predictors Over Baseline

The response time Concealed Information Test (RT-CIT) can help to reveal whether a person is concealing the knowledge of a certain information detail. During the RT-CIT, the examinee is repeatedly presented with a probe, the detail in question (e.g., murder weapon), and several irrelevants, other details that are similar to the probe (e.g., other weapons). These items all require the same keypress response, while one further item, the target, requires a different keypress response. Examinees tend to respond to the probe slower than to irrelevants, when they recognize the former as the relevant detail. To classify examinees as having or not having recognized the probe, RT-CIT studies have almost always used the averaged difference between probe and irrelevant RTs as the single predictor variable. In the present study, we tested whether we can improve classification accuracy (recognized the probe: yes or no) by incorporating the average RTs, the accuracy rates, and the SDs of each item type (probe, irrelevant, and target). Using the data from 1,871 individual tests and incorporating various combinations of the additional variables, we built logistic regression, linear discriminant analysis, and extra trees machine learning models (altogether 26), and we compared the classification accuracy of each of the model-based predictors to that of the sole probe-irrelevant RT difference predictor as baseline. None of the models provided significant improvement over the baseline. Nominal gains in classification accuracy ranged between –1.5% and 3.1%. In each of the models, machine learning captured the probe-irrelevant RT difference as the most important contributor to successful predictions, or, when included separately, the probe RT and the irrelevant RT as the first and second most important contributors, respectively.

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.

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 (dE1 = 0.85 [0.51; 1.18]; dE2 = 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 (dE2 = 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.