Abstract
The present study investigates age and gender differences in lie-telling during the sensitive developmental phase of adolescence, using a multi-informant approach. Data from a large, multi-national dataset was used, including 25,643 participants aged 11–18 years across 24 societies, using the Child Behavior Checklist (CBCL) and Youth Self-Report (YSR). Mixed models were applied to examine both linear and curvilinear age trends, gender differences, and discrepancies between self- and parental reports on lying. The findings revealed that boys consistently showed higher frequencies of lying across all ages and informants, highlighting a robust gender difference. Also, significant mean-level age trends in lying were found, which however differed across informants. Adolescents’ reporting showed an inverted U-shape pattern in lying frequency with growing age, peaking around mid-adolescence, while parental reports showed a U-shaped trend in their child’s lying frequency across age, although curvilinearity was less pronounced. The highest discrepancy between self- and parental reports of adolescent lying was situated in mid-adolescence, likely due to both a parental truth bias and the increased sophistication of adolescents in concealing their lies. These results suggest that informant agreement during mid-adolescence on rather undesirable behavior may be particularly challenging. These informant discrepancies on lying may also have clinical significance, and future research may further address to what extent each of these informant perspectives generate relevant information to understand mental health outcomes in youth.