In the field of education, teaching practice is the space-time where/when learning-teaching theory becomes tangible, observable. In research on teacher educators, empirical methods such as self- study, case study, enquiry into practice, action research and formative interventions have been used to embody, enact or bridge the ‘gap’ between theory and practice. Today, while the literature continues to highlight the problematic relationship between theory and practice, and show innovative approaches to address it, it often does not present the voice of teacher educators in search of possible solutions. This study sought to remedy this dissonance by allowing four teacher educators from a teacher education programme in Colombia to address contradictions in their theoretical and practical understanding of conceptual tools and to propose how to align them. They did this through a formative intervention that used an adapted version of the change laboratory proposed by Engestr¨om (1987).

Applying a multi-layered abductive approach, the analysis of the actions and activities that the teacher educators collectively carried out during the intervention yielded an overarching conclusion. The actions triggered an expansive pedagogical learning cycle, which led the teacher educators to redefine the object of the activity of teaching about teaching in their activity system. The findings indicate that three main conditions are essential for teacher educators to redefine this activity. The first is intentional and guided reflective thinking, the second is shared meaning and understanding of the conceptual tools under investigation, and the third is the existence of conditions of social participation in learning.

The significance of this study can be seen in three broad themes that underlie this research. A new perspective and adaptations of Yrj¨o Engestr¨om’s (1987) concept of expansive learning. A theo-practical understanding of teacher educators’ learning, and a proposal to look at the unit of analysis of Vygotsky’s (1987) cultural-historical theory and cultural-historical activity theory from a different perspective.