Abstract

Joint attention is characterized by openness: when two agents jointly attend to an object, they are immediately and fully aware of each other's attentional states. Existing accounts of openness involve a mental picture in which two agents attend to the same object and where openness is then 'added'. I argue that the experience of openness comes first. Young infants operate under a tacit assumption of openness: they behave as if attentional states were open even when they aren't. The ability to engage in joint attention doesn't arise when infants begin to experience openness, but rather when they can limit these experiences to open interactions. For this, they depend on cognitive processes that detect non-open interactions. Some of these processes develop early and don't require the representation of others' mental states. Other processes develop later and require the infant to differentiate between herself and others as subjects of attentional states.