A Head-to-Head Comparison of the Incremental Validity of Four Major Mentalizing Tests Against Mentalizing Self-Reports: A Preregistered Study in Adults

Mentalizing, the ability to attribute mental states to oneself and others, is commonly assessed using a variety of neuropsychological tests. However, whether these tools capture unique aspects of mentalizing or primarily reflect reasoning and language abilities remains unclear. This pre-registered study examines the incremental validity of four widely used mentalizing assessments: the Hinting Task, the Faux-Pas test, the Reading the Mind in the Eyes Test, and Frith–Happé Animations. We aim to determine whether these tests uniquely predict self-reported mentalizing abilities in daily life (using various self-reported indices of mentalizing) beyond general reasoning and language skills. Beyond testing the incremental validity of each test, we will also conduct several exploratory analyses, including head-to-head comparisons between the performance-based tests and multimodal associations between tests and self-report questionnaires. This study will clarify the relevance of mentalizing assessments, offering valuable implications for research and clinical practice.