Exploring insight into unfamiliar face recognition ability: The case from developmental prosopagnosia

This study aims to explore the relationship between face processing ability and individuals' insight into that ability, with a particular focus on those who ‘self-refer’ as having face recognition difficulties; namely, individuals with developmental prosopagnosia (DP). Specifically, the study examines whether self-referred individuals represent a subpopulation with elevated levels of insight into their face recognition performance compared to the general population. Using Bayesian hierarchical modelling, we compared performance across the ‘objective’ Cambridge Face Memory Test (CFMT) and the ‘subjective’ 20-item Prosopagnosia Index (PI20) in self-referred DP individuals (N = 279) and normative populations (N = 1,344)-this statistical approach allows for flexible, probabilistic predictions about performance based on subjective insight and group membership, enabling more nuanced comparisons. Despite hypotheses that self-referring participants might demonstrate superior metacognitive insight, results showed no credible evidence of enhanced alignment between PI20 and CFMT measures in this group compared to normative samples. Overall, these findings underscore the limitations of current diagnostic tools, emphasizing the need for psychometric refinement to address measurement noise and improve the reliability of subjective self-assessments. This work contributes to understanding individual variability in cognitive insight and highlights the challenges of identifying DP based on subjective and objective alignment.