The role of motivation to avoid detection in reaction time-based concealed information detection

No practice effect on the classification accuracy of the response time concealed information test

The Response Time Concealed Information Test can reveal that a person recognizes a relevant item (probe, e.g., a murder weapon) among other, irrelevant items (controls), based on slower responses to the probe compared to the controls. A previous study (Lukács, 2022, JARMAC) analyzed the data of 14 experiments and demonstrated that classification accuracy is increased by increased test length (i.e., increased number of trials included in the analysis). However, that study left the important question open whether prior practice (whose trials are not included in the analysis) influences the classification accuracy of subsequent testing (i.e., subsequent trials included in the analysis). Reanalyzing the same data from the 14 experiments (comprising 2223 individual tests), we show that different sections of the test (each with the same number of trials), such as the first and second half of each examined test, do not differ substantially in their classification accuracy. The main implications for real-life application are that, at least up to about 600 trials, prior practice does not affect subsequent tests' results, and the number of examined relevant items or their order of presentation may be freely chosen without compromising the method's validity.

Speed versus accuracy instructions in the response time concealed information test

The response time concealed information test (RT-CIT) can reveal that a person recognizes a relevant item (probe) among other, irrelevant items, based on slower responding to the probe compared to the irrelevant items. Thereby, if this person is concealing knowledge about the relevance of this item (e.g., recognizing it as a murder weapon), this deception can be unveiled. In the present paper, we examined the impact of a speed versus accuracy instruction: Examinees (N = 235) were either presented with instructions emphasizing a focus on speed, with instructions emphasizing a focus on accuracy, or with no particular speed or accuracy instructions at all. We found that although participants responded to the probe and the irrelevants marginally faster when they had received instructions emphasizing speed, there was no significant difference between RTs of the different experimental groups and crucially no significant difference between the probe-irrelevant RT differences either. This means that such instructions are unlikely to benefit the RT-CIT, but it also suggests that related deliberate manipulation (focusing on speed on or accuracy) is unlikely to decrease the efficiency of the RT-CIT-contributing further evidence to the RT-CIT's resistance to faking.

Dispersion matters: Diagnostics and control data computer simulation in Concealed Information Test studies

Binary classification has numerous applications. For one, lie detection methods typically aim to classify each tested person either as "liar" or as "truthteller" based on the given test results. To infer practical implications, as well as to compare different methods, it is essential to assess the diagnostic efficiency, such as demonstrating the number of correctly classified persons. However, this is not always straightforward. In Concealed Information Tests (CITs), the key predictor value (probe-irrelevant difference) for "truthtellers" is always similar (zero on average), and "liars" are always distinguished by a larger value (i.e., a larger number resulting from the CIT test, as compared to the zero baseline). Thereby, in general, the larger predictor values a given CIT method obtains for "liars" on average, the better this method is assumed to be. This has indeed been assumed in countless studies, and therefore, when comparing the classification efficiencies of two different designs, the mean difference of "liar" predictor values in the two designs were simply compared to each other (hence not collecting "truthteller" data to spare resources). We show, based on the meta-data of 12 different experimental designs collected in response time-based CIT studies, that differences in dispersion (i.e., variance in the data, e.g. the extent of random deviations from the zero average in case of "truthtellers") can substantially influence classification efficiency-to the point that, in extreme cases, one design may even be superior in classification despite having a larger mean "liar" predictor value. However, we also introduce a computer simulation procedure to estimate classification efficiency in the absence of "truthteller" data, and validate this procedure via a meta-analysis comparing outcomes based on empirical data versus simulated data.

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.

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.

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.

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.

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.

Financial Incentive Does Not Affect P300 in the Complex Trial Protocol (CTP) Version of the Concealed Information Test (CIT) in Malingering Detection. II. Uninstructed Subjects

Well-known research showed that the skin conductance response (SCR) of the Autonomic Nervous System (ANS) in the Concealed Information Test (CIT) is usually augmented in participants who are financially and motivationally incentivized to beat the CIT. This is not what happens with Reaction Time (RT)-based CITs, P300 CITs based on the 3-stimulus protocol, nor on the P300-based complex trial protocol for detection of malingering (however these tests differ from forensic CITs). The present report follows up the Rosenfeld et al. (1, 2) 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. The "CIT effect" (probe-minus-irrelevant P300 differences) did not differ among incentive groups, although as previously, semantic memory-evoked P300s exceeded episodic memory evoked P300s. An effect of specific test-beating instructions was found to enhance the CIT effect for semantic information.

Self-initiated versus instructed cheating in the physiological Concealed Information Test

The validity of the Concealed Information Test (CIT) to detect recognition of critical details has been demonstrated in hundreds of laboratory studies. These studies, however, lack the factor of deliberate intent to deceive. This disparity between research and practice may affect the generalizability of laboratory based CIT findings. In the current study, 65 out of 174 participants cheated on their own initiative in a trivia quiz. These self-initiated cheaters were compared to 68 participants who were explicitly requested to cheat. Skin conductance, heart rate, and respiration were found to detect concealed information related to cheating. No significant differences emerged between self-initiated and instructed cheaters, supported by Bayesian statistics showing substantial evidence for the null hypothesis. The data demonstrate that the validity of the CIT is not restricted to instructed deception. This finding is encouraging from an ecological validity perspective and may pave the way for further field implementation of memory detection.

Memory-Based Deception Detection: Extending the Cognitive Signature of Lying From Instructed to Self-Initiated Cheating

From a cognitive perspective, lying can be regarded as a complex cognitive process requiring the interplay of several executive functions. Meta‐analytic research on 114 studies encompassing 3,307 participants (Suchotzki, Verschuere, Van Bockstaele, Ben‐Shakhar, & Crombez, 2017) suggests that computerized paradigms can reliably assess the cognitive burden of lying, with large reaction time differences between lying and truth telling. These studies, however, lack a key ingredient of real‐life deception, namely self‐initiated behavior. Research participants have typically been instructed to commit a mock crime and conceal critical information, whereas in real life, people freely choose whether or not to engage in antisocial behavior. In this study, participants (n = 433) engaged in a trivia quiz and were provided with a monetary incentive for high accuracy performance. Participants were randomly allocated to either a condition where they were instructed to cheat on the quiz (mimicking the typical laboratory set‐up) or to a condition in which they were provided with the opportunity to cheat, yet without explicit instructions to do so. Assessments of their response times in a subsequent Concealed Information Test (CIT) revealed that both instructed cheaters (n = 107) and self‐initiated cheaters (n = 142) showed the expected RT‐slowing for concealed information. The data indicate that the cognitive signature of lying is not restricted to explicitly instructed cheating, but it can also be observed for self‐initiated cheating. These findings are highly encouraging from an ecological validity perspective.

Geven, Ben‐Shakhar, Kindt and Verschuere point out that research on deception detection usually employs instructed cheating. They experimentally demonstrate that participants show slower reaction times for concealed information than for other information, regardless of whether they are explicitly instructed to cheat or whether they can freely choose to cheat or not. Finding this ‘cognitive signature of lying’ with self‐initiated cheating too is argued by the authors to strengthen the external validity of deception detection research. [75]

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.

An Investigation on the Detectability of Deceptive Intent about Flying through Verbal Deception Detection

Background:

Academic research on deception detection has largely focused on the detection of past events. For many applied purposes, however, the detection of false reports about someone’s intention merits attention. Based on the verbal deception detection paradigm, we explored whether true statements on intentions were more detailed and more specific than false statements on intentions, particularly when instructed to be as specific as possible.

Method:

Participants (n = 222) lied or told the truth about their upcoming travel plans either providing ‘as much information as possible’ (standard instructions) or being ‘as specific as possible’ (i.e., mentioning times, locations, places; specific instructions), resulting in four conditions (truthful vs. deceptive intention by standard vs. specific instructions). We collected data via a custom-made web app and performed automated verbal content analysis of participants’ written answers.

Findings:

We did not find a significant difference in the specificity of participants’ statements. The instruction to be as specific as possible promoted more specific information but did not help to discern honest from deceptive flying intentions.

Conclusion:

The experiment reported here attempted to demonstrate automated verbal deception detection of intentions. The difficulty in capturing genuine intentions, and the non-intrusive, non-interactive questioning approach might explain the null findings and raise questions for further research. We conclude with suggestions for a novel framework on semi-interactive information elicitation.