Attachment theory is historically bound up with the cinematic apparatus and the time-sampling method of data recording. Interestingly, it has inspired few non-documentary films and still fewer auteur films. This paper explores the overt scenic representation of development theory in general and John Bowlby's conceptual paradigm of “internal working models” in particular in the classroom scenes in Richard Linklater's auteur film Boyhood (2014) as well an implicit, perhaps unconscious, leaning on Peter Fonagy's “mentalization” model in between scenes. I argue that Linklater used aspects of the production of empirical data that attachment research sought to document in order to represent cinematic character development across the “lifespan.” As such, Boyhood taps into the potential that the attachment model of development can play within the cinematic medium, opening new vistas into the cinematic study of the personality in character portraits.