The 'New Paradigm' of Sociology of Childhood famously maintains that childhood is socially constructed and supposedly places a much greater emphasis on the agency of children: children should not simply be framed as the passive receivers of socialisation. The aim of this article is to demonstrate that such a 'social construction' of childhood is not concretely articulated and that the theoretical understanding of the 'social construction' of childhood is simply delegated to historiographical or ethnographic accounts. In doing so, it advances a new criticism of the New Paradigm and radicalises previous ones. Here, key is the theoretical engagement with the concept of 'human capital': foregrounding its critique, this article proposes the link between 'human capital' as a neoliberal version of labour power and the concept of socialisation. The aim is to show that the 'social construction' of childhood is central, but the New Paradigm uses categories that are at the same time founded on neo-liberal views and abstracted from concrete social relations. This article maintains that a concrete critique of processes of socialisation (which is here understood as the socialisation of childhood as human capital) is needed instead of abstract critique of reified childhood. Two alternative pedagogical practices are used to provide an example of such a concrete critique.