The symposium will analyse various forms of social interaction, their functions and the preconditions that make them possible, in both natural and synthetic agents, and in physical and software environments. In particular, we wish to address the origins and development of social expertise with respect to the concrete realisation of an artificial system. This includes both the external behaviour and the internal cognitive and motivational abilities of an agent. This means that the discussions should focus on cross-technological concepts (excluding those restricted to a specific hardware or software technology). This general focus is necessary in order to find a common language between participants from different fields.