This essay seeks to clarify the paradigm shift from object-centered to human-centered research and design. It suggests abandoning the technological determinism that underlies the industrial era conceptions of human-machine interactions, which still informs much of current human factors or ergonomic research and making room for models of human-machine interactions that are derived from the human use of language, conversation and play. The essay demonstrates the significance of this shift by contrasting two ways users account for their involvement with artifacts: extrinsic and intrinsic motivation. It contends that intrinsic motivation largely escapes the traditionally object-centered scientific research methods. To inquire into the use of intrinsically motivating artifacts and aid the design of artifacts that have a chance to be intrinsically motivating, therefore, demands taking a different epistemological path, one that acknowledges the crucial use of language. This essay outlines such a path, pursues it and ends with practical suggestions for the design of artifacts that enable intrinsically motivating interfaces to arise.