Fonagy and colleagues coined the term reflective function (RF) to describe the developmental achievement whereby children acquire the capacity to mentalize the thoughts, feelings, intentions and desires of self and others (Fonagy et al. 2002). Drawing from developmental theory and research, they argue that the capacity for RF is dependent on the quality of interpersonal interactions, particularly the emotional relationship between infant and caregivers.

Reflective Function has been operationalized by Fonagy and colleagues in order to evaluate the quality of mentalization in the context of attachment relationships. In a study examining the role of parents’ mentalizing skills and its relation to their infant's attachment pattern, Fonagy et al. (1996) found that RF mediated the relation between