Evidence suggesting superiority of visual (verbal) vs. auditory test presentation modality in the P300-based, Complex Trial Protocol for concealed autobiographical memory detection

One group of participants received a series of city name stimuli presented on trials of the Complex Trial Protocol (CTP) version of a P300-based, concealed information test (CIT). Stimuli were presented on alternating trials in either auditory or visual presentation modality. In 1/7 of the trials the participant's home town (probe) repeatedly appeared in a series of 6 other (irrelevant) repeated city names. In both modalities, probe stimuli produced larger P300s than irrelevant stimuli. Visual stimuli produced shorter behavioral reaction times and P300 latencies, as well as larger P300 probe amplitudes, probe-irrelevant amplitude differences, and individual diagnostic accuracies than the same stimuli presented in the auditory modality. Possible reasons for these effects are discussed, and subject to discussed limitations, the applied conclusion reached is that in all CITs, visual presentation of stimuli, if feasible, should be preferentially used.

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.

Tracking the truth: the effect of face familiarity on eye fixations during deception

In forensic investigations, suspects sometimes conceal recognition of a familiar person to protect co-conspirators or hide knowledge of a victim. The current experiment sought to determine whether eye fixations could be used to identify memory of known persons when lying about recognition of faces. Participants' eye movements were monitored whilst they lied and told the truth about recognition of faces that varied in familiarity (newly learned, famous celebrities, personally known). Memory detection by eye movements during recognition of personally familiar and famous celebrity faces was negligibly affected by lying, thereby demonstrating that detection of memory during lies is influenced by the prior learning of the face. By contrast, eye movements did not reveal lies robustly for newly learned faces. These findings support the use of eye movements as markers of memory during concealed recognition but also suggest caution when familiarity is only a consequence of one brief exposure.

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]

It's a match!? Appropriate item selection in the Concealed Information Test

BACKGROUND

While the Concealed Information Test (CIT) can determine whether examinees recognize critical details, it does not clarify the origin of the memory. Hence, when unknowledgeable suspects are contaminated with crime information through media channels or investigative interviews, the validity of the CIT can be compromised (i.e. false-positive outcomes). Yet, when the information was disclosed solely at the category level (e.g. the perpetrator escaped in a car), presenting specific items at the exemplar level (e.g. Citroën, Opel, or Volkswagen) might preclude this problem. However, diminished recollection for exemplar-level details could attenuate the CIT effect for knowledgeable suspects, thereby leading to false negatives. The appropriate item level for memory detection to reach an optimal balance between sensitivity and specificity remains elusive. As encoding, retention, and retrieval of information may influence memory performance and thereby memory detection, the current study investigated the validity of the CIT on both categorical and exemplar levels.

RESULTS

Participants planned a mock robbery (n = 165), with information encoded at the category (e.g. car) or exemplar (e.g. Citroën) level. They were tested immediately or after a one-week-delay, with a response time-based CIT consisting of questions at the categorical or exemplar level. An interaction was found between encoding and testing, such that CIT validity based on reaction time was higher for "matching" (e.g. exemplar-exemplar) than for "mismatching" (e.g. exemplar-categorical) items, while immediate versus one week delayed testing did not affect the outcome.

CONCLUSION

Critically, this indicates that what constitutes a good CIT item depends on the way the information was encoded. This provides a challenge for CIT examiners when selecting appropriate items.

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.

Variation of picture angles and its effect on the Concealed Information Test

BACKGROUND

The reaction time-based Concealed Information Test (RT-CIT) is a memory paradigm used to detect crime-related knowledge. However, this would also imply that the RT-CIT would be vulnerable to factors that are known to compromise object recognition or memory integrity. From this perspective, one key issue is whether "guilty" memory can be detected if the crime-related images are photographed at different angles from what the perpetrator saw, which is almost always the case in the field. To investigate this, here we manipulated the deviation angles, from 0° to 330° in 11 steps, between the study and test phases to assess how the RT-CIT holds up against angular rotations.

RESULTS

We observed a robust RT-CIT effect at all deviation angles for both deep-encoders (Experiment 1) and shallow-encoders (Experiment 2). The RT-CIT was effective within the first 250 or so trials for both encoding groups, with smaller probe-irrelevant differences beyond that.

CONCLUSIONS

With appropriate encoding and memory strength, RT-CIT images do not necessarily have to match the exact angle of the perpetrator's perspective at the time of the crime. Unnatural angles such as 90° and 270° or unconventional rotational axes may require caution. Trial number under 250 trials show maximal Probe-Irrelevant difference, but more trials may add power to improve detection accuracy.

Two Cases of Malingered Crime-Related Amnesia

Amnesia is a frequent claim in major crimes, and it is estimated that the complete or partial absence of memory following a crime ranges from 25% to 50% of total cases. Although some cases may constitute a genuine form of amnesia, due to organic-neurological defects or psychological causes, and possibly combined with a dissociative or repressive coping style after an extreme experience, malingering is still fairly common in offenders. Therefore, one of the main goals in medico-legal proceedings is to find methods to determine the credibility of crime-related amnesia. At present, a number of lie and memory detection techniques can assist the forensic assessment of the reliability of declarative proof, and have been devised and improved over the past century: for example, modern polygraphs, event-related potentials, thermal imaging, functional magnetic resonance imaging, kinematic, and facial analysis. Other ad hoc psychological tests, such as the so-called Symptom Validity Test (SVT) and Performance Validity Test (PVT), as well as the autobiographical Implicit Association Test (aIAT), can also be used. To date, however, there is little evidence or case reports that document their real usefulness in forensic practice. Here, we report two cases of crime-related amnesia, whereby both defendants, who were found guilty of homicide, appeared to exhibit dissociative amnesia but where the application of SVTs, PVTs, and aIAT detected a malingered amnesia.

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.

Identification performance across the life span: Lineups and the reaction time-based Concealed Information Test

Cognitive and social factors can deteriorate eyewitness identification performance in children and older adults. An identification procedure that mitigates the effect of such factors could be beneficial for child and older adult witnesses. In a field experiment, we mapped identification performance in a large community sample (N = 1239) across the lifespan (ages 6-79 years) for two different identification procedures: classic lineups and reaction time-based Concealed Information Test (RT-CIT). Visitors of a science museum or science fair witnessed a recorded mock theft and then took either a classic lineup, or the RT-CIT. Young adults (18-35-year-olds) outperformed younger and older age groups in lineup performance. The RT-CIT showed a moderate capacity to diagnose face recognition and absence of recognition in the target-absent condition. Age did not affect identification with the RT-CIT. However, children were often not able to follow the RT-CIT instructions, leading to a large number of exclusions. A direct comparison of lineup vs. RT-CIT performance showed that children and adolescents showed better identification performance in RT-CIT than lineups. For young adults, there was no difference between the two procedures. The trend turned around at mid-adult age who showed better identification performance when they were given a lineup compared to an RT-CIT. These findings suggest that the RT-CIT might be considered an alternative identification procedure for children and adolescents, offering protection for innocent suspects.

Retroactive memory interference reduces false positive outcomes of informed innocents in the P300-based concealed information test

In the Concealed Information Test (CIT), differential responses between crime-relevant and crime-irrelevant items are indicative of concealed knowledge of a crime, and are used to classify an individual as either "guilty" or "innocent". However, when crime-relevant items are leaked before the test, an innocent examinee can exhibit enhanced responses to the crime-relevant items, thus causing such examinee to be wrongly classified as guilty. In an attempt to solve this problem, we examined the role of retroactive memory interference (RI) in differentiating informed innocents from guilty participants, using a P300-based CIT. Participants acquired crime-related knowledge either by committing a mock crime (guilty group) or reading a paper that described a mock crime (informed innocent group). Subsequently, the participants within each condition were randomly assigned to either an RI group, where they were exposed to new crime-related details before the CIT, or a control group. We found an interaction between guilty and RI groups: in the guilty group, there was a significant difference in P300 amplitude between the probe and irrelevant items, regardless of RI manipulation, whereas in the informed innocent group, a difference in P300 amplitude between the probe and irrelevant items was significant only in the control group, but not in the RI group. This led to an improved detection rate of the informed innocents (31% for the control group vs. 77% for the RI group). These results suggest that RI manipulation could be used to reduce the false positive outcomes of informed innocents without affecting the detection rate of guilty participants.

The impact of reducing cognitive load in RT and P300 concealed information tests with importance related fillers

Lukács et al. (2017) enhanced the Reaction Time Concealed Information Test (RT CIT) by incorporating "filler" items. Fillers are intended to increase attention and cognitive load, which should potentially enhance the P300 based CIT (P300-CIT) too. Despite these hypotheses, Olson et al. (2020) found no clear effects of fillers on P300 amplitude and suggested that excessive cognitive load may counteract an increase in attention. Wojciechowski and Lukács (2022) introduced "importance-related" fillers to the RT-CIT in an imaginary mock crime scenario, theorizing they would be more intuitive and easier for participants to follow. This study aims to replicate their findings in a classic episodic mock crime scenario, and with semantic information, to test if a fillers-related enhancement effect on P300 may be observed when cognitive load is reduced. The study compares three protocols: the importance-themed enhanced CIT (E-CIT), a less cognitively demanding version of the E-CIT, the inducer CIT (I-CIT), and the classic three-stimulus protocol (3SP-CIT). The study investigates whether the I-CIT yields a superior P300-CIT effect due to reduced cognitive load and induced semantic context of importance. Reaction time analyses replicated the RT-CIT effect enhancement in the E-CIT compared to the classic 3SP-CIT. Elevated response times in the E-CIT compared to the 3SP-CIT and I-CIT suggest higher cognitive load in the E-CIT. Response times were comparable between the 3SP-CIT and I-CIT, suggesting similar cognitive load. For the P300-CIT results, similar to Olson et al. (2020), fillers did not affect P300 amplitude or latency in the E-CIT group, with Bayes factors supporting the null. Contrary to expectations, no clear enhancement of P300 was observed in the I-CIT, suggesting that cognitive load imposed by fillers does not counteract P300 amplitude.

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 trajectory of crime: Integrating mouse-tracking into concealed memory detection

The autobiographical implicit association test (aIAT) is an approach of memory detection that can be used to identify true autobiographical memories. This study incorporates mouse-tracking (MT) into aIAT, which offers a more robust technique of memory detection. Participants were assigned to mock crime and then performed the aIAT with MT. Results showed that mouse metrics exhibited IAT effects that correlated with the IAT effect of RT and showed differences in autobiographical and irrelevant events while RT did not. Our findings suggest the validity of MT in offering measurement of the IAT effect. We also observed different patterns in mouse trajectories and velocity for autobiographical and irrelevant events. Lastly, utilizing MT metric, we identified that the Past Negative Score was positively correlated with IAT effect. Integrating the Past Negative Score and AUC into computational models improved the simulation results. Our model captured the ubiquitous implicit association between autobiographical events and the attribute True, and offered a mechanistic account for implicit bias. Across the traditional IAT and the MT results, we provide evidence that MT-aIAT can better capture the memory identification and with implications in crime detection.