The present study aimed to evaluate the nomological network validity of the Movie for the Assessment of Social Cognition (MASC) in its Italian translation, addressing distinct research questions in three independent samples of Italian participants comprising adolescent nonclinical participants (N = 393), adult nonclinical participants (N = 193), and adult outpatients with a Personality Disorder (PD) diagnosis who sought psychotherapy treatment (N = 59). In all three samples the MASC proved to be a reliable measure of mentalizing ability, with Cronbach’s α values ranging from .70 to .78. In both nonclinical adolescents and nonclinical adults, the MASC scores correlated significantly and meaningfully with the Reading the Mind in the Eyes Test scores. In nonclinical adults, the MASC scores showed significant (albeit modest) correlations with self-reported measures of attachment styles. Finally, in adult outpatients, the MASC “no ToM” scores, that are specific errors that indicating non mentalistic responses, correlated significantly with interview-based measures (Spearman r = .41, p < .01) and self-reported measures (Spearman r = .37, p < .01) of borderline personality disorder (BPD), as well as with measures of emotion dysregulation, (Spearman r = .37, p <.01). As a whole, these findings highlight the validity of the MASC as a measure of mentalization and are consistent with Fonagy and colleagues’ (i.e., Bateman & Fonagy, 2004b; Fonagy, 1991) model of mentalization and its role in personality pathology
