Wiktionary
n. (context psychology English) The ability to understand mental state that underlies the overt behaviour of oneself or others.
Wikipedia
In psychology, mentalization is the ability to understand the mental state, of oneself or others, that underlies overt behaviour. Mentalization can be seen as a form of imaginative mental activity that lets us perceive and interpret human behaviour in terms of intentional mental states (e.g., needs, desires, feelings, beliefs, goals, purposes, and reasons). Another term that David Wallin has used for mentalization is "Thinking about thinking".
While the Theory of Mind has been discussed in philosophy at least since Descartes, the concept of mentalization emerged in psychoanalytic literature in the late 1960s, and became empirically tested in 1983 when Heinz Wimmer and Josef Perner ran the first experiment to investigate when children can understand false belief, inspired by Daniel Dennett's interpretation of a Punch and Judy scene.
The field diversified in the early 1990s when Simon Baron-Cohen and Uta Frith, building on the Wimmer and Perner study, and others merged it with research on the psychological and biological mechanisms underlying autism and schizophrenia. Concomitantly, Peter Fonagy and colleagues applied it to developmental psychopathology in the context of attachment relationships gone awry. More recently, several child mental health researchers such as Arietta Slade, John Grienenberger, Alicia Lieberman, Daniel Schechter, and Susan Coates have applied mentalization both to research on parenting and to clinical interventions with parents, infants, and young children.
Mentalization has implications for attachment theory and self-development. According to Peter Fonagy, individuals without proper attachment (e.g., due to physical, psychological, or sexual abuse), can have greater difficulty developing mentalization-abilities. Attachment history partially determines the strength of mentalizing capacity of individuals. Securely-attached individuals tend to have had a primary caregiver that has more complex and sophisticated mentalizing abilities. As a consequence, these children possess more robust capacities to represent the states of their own and other people’s minds. Early childhood exposure to mentalization can protect the individual from psychosocial adversity. This theory needs further empirical support.