Some types of species exploit the external environment to support their cognitive processes, in the sense of patterns created in the environment that function as external mental states and serve as an extension to their mind. In the case of social species the creation and exploitation of such patterns can be shared, thus obtaining a form of shared mind or collective intelligence. This paper explores this shared extended mind principle for social species in more detail. The focus is on the notion of representational content in such cases. Proposals are put forward and formalised to define collective representational content for such shared external mental states. Two case studies in domains in which shared extended mind plays an important role are used as illustration. The first case study addresses the domain of social ant behaviour. The second case study addresses the domain of human communication via the environment. For both cases simulations are described, representation relations are specified and are verified against the simulated traces. © 2006 Elsevier B.V. All rights reserved.