The question of what it means to be aware of others as subjects of mental states is often construed as the question of how we are epistemically justified in attributing mental states to others. The dominant answer to this latter question is that we are so justified in virtue of grasping the role of mental states in explaining observed behaviour. This chapter challenges this picture and formulates an alternative by reflecting on the interpretation of early joint attention interactions. It argues (...) that the standard picture is committed to an implausible account of children's awareness of the co-attender's focus of attention. On a more natural interpretation, children engaged in joint attention perceptually recognize the co-attender's attitude to some object, as something like the (correct) answer to the question of what the object is like. The developmentally basic case is not that of attributing mental states as the causes of observed behaviour but of understanding perceived attitudes and actions as appropriate responses to the shared world. The chapter concludes by exploring how this developmental claim bears on mature adult knowledge of other minds. (shrink)