Why did ‘Theory of Mind’ take off when it did, and what, if anything, holds this very diverse approach together? The focus of research within developmental psychology since the 1960s had been the examination of Piaget’s claims about cognitive development. The agenda had quickly become to demonstrate, primarily through experiments, that young children could (contrary to Piaget’s claims) succeed on various ‘cognitive’ tasks given the right context. Yet, by the 1980s, the research had still neither undermined Piagetian theory, nor opened up any radical alternative. Theory of Mind was conveniently to hand to provide another ‘grand’ theory to subject to experimental test, and in many ways business continued as usual. However, ‘context’ came to be regarded as no longer an important issue for research but a contaminant, and the experiments became stipulative rather than exploratory. In the attempt to eliminate context in order to test children’s real understanding of other people, the experiments themselves have come to constitute the largely implicit ‘theory’ behind Theory of Mind. The experiments presuppose that making sense of other people is essentially about making indirect inferences from the apparent (observable behaviour) to the real (hidden mental structures). It is this experimental paradigm of signification—of an indirect or ‘round-about’ relation between observations and the object of study—that ultimately holds the Theory of Mind approach together.