The goal of the present deliverable is to provide a developmental analysis of attentional intersubjectivity, which, as we show below, is a more inclusive notion than the more commonly used term ‘joint attention’. The use of the term ‘joint attention’ is not consistent in the literature, sometimes referring to the general phenomenon when two or more subjects attend to the same target, sometimes to more reciprocal situations in which the subjects also are aware of attending to the same target. Most (...) often solely visual attention has been described, but implicitly the descriptions have been thought to generalize to other modalities. The concepts introduced in this deliverable constitute an attempt to construct a coherent framework that will allow for distinguishing and comparing the range of behaviours that in the literature have been addressed as ‘joint attention’ behaviours. By attentional intersubjectivity we refer to the general case when two or more subjects simultaneously focus their attention on the same target. Attentional intersubjectivity will be further divided into types, according to which behaviours that are typically associated with attentional intersubjectivity occur during the interaction, and in which combinations. The result is that the over-all behaviour of the subjects during different types of attentional intersubjectivity differs. Our contentions are that: a) the types of attentional intersubjectivity identified in this report build on each other cumulatively and constitute different levels, and b) these levels correspond to evolutionary and developmental stages. In saying that the types are cumulative we mean that there is a progress by successive stages where each type is causally dependent on the type preceding it, and, furthermore, has increased in complexity as compared to previous types. While attentional intersubjectivity involves several perceptual modalities, for practical reasons, this study primarily concerns the visual modality. Our analysis is, however, intended also to be applicable to these other modalities. (shrink)