Humans seem to readily track their conspecifics’ mental states, such as their goals and beliefs from early infancy. However, the underlying cognitive architecture that enables such powerful abilities remains unclear. Here I will propose that a basic representational structure, the belief file, could provide the foundation for efficiently encoding, and updating information about, others’ beliefs in online social interactions. I will discuss the representational possibilities offered by the belief file and the ways in which the repertoire of mental state reasoning (...) is shaped by the characteristics of its constituents. A series of questions will be outlined concerning the representational skeleton of the belief file, sketching a possible structure that supports the rapid encoding and re-identification of belief related information. After analyzing the possible limitations of the belief attribution system, I will examine some of its characteristics that might enable a flexibility that is often neglected. I will suggest that operations involving belief files are not impeded by the absence of precise first-person information regarding their contents. In fact, the system permits manipulations with “empty” belief files, allowing humans to ascribe beliefs to conspecifics based on little or no direct information regarding the content of the mental state. Such an analysis aims to advance our understanding of how spontaneous belief attribution may be performed, and to provide an insight into the possible mechanisms that allow humans to successfully navigate the social world. (shrink)