Recent accounts of mindreading—i.e., the human capacity to attribute mental states to interpret, explain, and predict behavior—have suggested that it has evolved through cultural rather than biological evolution. Although these accounts describe the role of culture in the ontogenetic development of mindreading, they neglect the question of the cultural origins of mindreading in human prehistory. We discuss four possible models of this, distinguished by the role they posit for culture: the standard evolutionary psychology model, the individualist empiricist model, the cultural empiricist model, and the radical socio-cultural constructivist model, which we favor. We motivate model by arguing that many forms of mental state ascription do not serve the function of simply describing inner states causally responsible for the behavior of a cognitive agent; rather, they relate the agent to her environment by characterizing her practical commitments. Making these practical commitments explicit has an important regulatory function in that it supports action coordination and alignment on joint goals. We propose a model of how the ascription of mental states may have evolved as a linguistic device to perform exactly this function of making agents’ practical commitments explicit.