Anyone who attempts to skip this problem, to jump over methodology in order to build some special psychological science right away, will inevitably jump over his horse while trying to sit on it. (Vygotsky, 1997a, p. 329) The reputation of educational research is tarnished less by the lack of replicable results than by the lack of any deeper theory that would explain why the thousands of experiments that make up the literature of the field appear to have yielded so little. (Olson, 2004, p. 25) Abstract: The discussion of design experiments has largely ignored the Vygotskian tradition of formative interventions based on the principle of double stimulation. This tradition offers a radical approach to learning reasearch which focuses on the agency of the learners. The principle of double stimulation is used and developed further in the intervention methodology called Change Laboratory, created in the Center for Activity Theory and Developmental Work Research at University of Helsinki. The paper analyzes the Change Laboratory methodology and its potential for generating expansive learning, using data from an intervention conducted in 2006 in the surgical unit of a university hospital in Finland. The analysis demonstrates how the agency of the learning collective developed hand-in-hand with the construction and implementation of a new organization of work by the collective. Such expansive learning goes beyond knowledge construction, resulting in materially anchored new practices.