Abstract
The standard view on explicit theory of mind development holds that children around the age of 4 years start to ascribe beliefs to themselves and others. At this age they begin to master FB tasks in which they have to ascribe a mistaken belief to someone else. The emerging competence in FB tasks goes hand in hand with the developing ability to master various tasks that also require the understanding of different perspectives, like the alternative naming game, false sign or identity tasks. Mental Files Theory allows to explain this developmental synchrony. It also helps to explain why older children struggle to understand that beliefs about an object depend on how one is acquainted with it (aspectuality), and why these difficulties disappear once children master second-order belief tasks at age 6. In this chapter, I focus on children’s developing mental file management, and how this accounts for the developmental synchrony of tasks that require taking into account different perspectives. In addition, I address several challenges for this view from the literature.