Lying emerges early during preschool age and the focus of previous research has been mainly on the ability to lie in preschool children. In this research, using a new procedure for measuring differences in the ability to lie, the aim was to examine the ability to lie in school-age children, as well as the cognitive and social correlates of children's success in lying. A total of 48 children, 16 children in each grade (first, fifth and eighth) of elementary school had the task to construct false autobiographic narratives and report them as convincingly as possible to convince others that it really happened to them. Convincingness of their video-recorded narratives was assessed by 15 independent observers. Based on specially constructed inventory, assessments of intelligence, verbal ability, peer group popularity and antisocial behavior of each child were collected from the class teacher. The results show that children aged 10 to 11 years and children aged 13 to 14 years were assessed as more convincing when lying compared to younger children, aged 6 to 7 years. However, there was no difference in the ability to lie between children aged 10 to 11 and children aged 13 to 14, nor a difference in the ability to lie between girls and boys. Children with higher school achievement and those who were assessed by the class teacher as more intelligent, verbally capable and more popular among peers were also assessed by a group of independent assessors as more convincing during reporting false autobiographic narratives.

Objective: This paper investigates the potential of cardiogram-derived traits from electrocardiogram (ECG) and impedance cardiogram (ICG) for biometric identification. Additionally, the influence of induced emotions on cardiogram attributes and their impact on identification accuracy is explored.Method: We compare 7 machine learning classifiers using a dataset gathered from 202 individuals to identify the highest-performing classifiers. Subsequently, we analyze three different feature sets employing (ECG-only, ICG-only, and both ECG and ICG). Additionally, we investigate the performance of classifiers under altered emotional states to assess classifiers’ robustness.Results: The analysis demonstrates that models employed with both ECG and ICG have the highest statistically significant accuracies. The best-performing Random Forest (RF) model using both ECG and ICG achieves an average accuracy of 97.2%. All models reveal a decrease in classification accuracies (~13%) when not trained and tested under identical emotional conditions.Conclusion: Our findings suggest that integration of ECG and ICG-based features could increase the accuracy of identification compared to a single-signal-based approach. Although certain models show slight robustness to altered emotional states, the effect of the emotion is evident and future selection of cardiogram-based features, as well as biometric models, should consider emotional responses.

The Concealed Information Test (CIT) detects whether an individual recognizes crime-relevant information, and eye tracking has been proposed as a non-invasive method for detecting this recognition. It remains unclear, however, whether individuals who are motivated to conceal their knowledge can voluntarily control their gaze and thereby undermine the test’s validity. We developed a novel free-viewing, parallel-presentation eye-movement-based CIT and administered it to 75 participants randomly assigned to three groups: Innocent, Informed Innocent, and Guilty. For each participant, twelve eye-tracking measures were calculated as differential (crime-relevant minus control) scores and analyzed using four supervised classifiers under a participant-wise, leave-two-out cross-validation, with accuracy reported at both the trial and participant levels. Cumulative dwell- and duration-based measures, together with glance and fixation counts, carried most of the discriminative signal. The classifiers demonstrated high accuracy when distinguishing between the naive and knowledgeable but non-concealing individuals, as well as between knowledgeable non-concealing individuals and culpable individuals. However, classification performance fell to chance-level probability when distinguishing naive and culpable individuals. Thus, participants who were motivated to avoid detection markedly reduced their distinctive eye-movement signature with voluntary gaze control, becoming indistinguishable from truly naive individuals. We discuss methodological implications for designing eye-movement-based CITs that exhibit greater resilience against voluntary gaze modulation.

The Concealed Information Test (CIT) detects whether an individual recognizes crime-relevant information, and eye tracking has been proposed as a non-invasive method for detecting this recognition. It remains unclear, however, whether individuals who are motivated to conceal their knowledge can strategically modulate their gaze and thereby undermine the test validity. We developed a novel free-viewing, parallel-presentation eye-movement-based CIT and administered it to 75 participants randomly assigned to three groups: Innocent, Informed Innocent, and Guilty. For each participant, twelve eye-tracking measures were calculated as differential (crime-relevant minus control) scores and analyzed using four supervised classifiers under a participant-wise, leave-two-out cross-validation, with accuracy reported at both the trial and participant levels. Cumulative dwell- and duration-based measures, together with glance and fixation counts, carried most of the discriminative signal. The classification model demonstrated high accuracy when distinguishing between the naive and knowledgeable but non-concealing individuals, as well as between knowledgeable non-concealing individuals and culpable individuals. However, classification performance fell to chance-level probability when distinguishing naive and culpable individuals. Thus, participants who were motivated to avoid detection markedly reduced their distinctive eye-movement signature with voluntary gaze control, becoming indistinguishable from truly naive individuals. We discuss methodological implications for designing eye-movement-based CITs that exhibit greater resilience against strategic, voluntary gaze modulation.