Background: Our theoretical perspectives direct our research processes. The article contributes to the debate on Cultural Historical Activity Theory (CHAT) and Dewey’s idea-based social constructivism, and to the debate on methodology and how the researcher’s theoretical stance guides the researcher in his or her work. Purpose: The article presents fundamental ideas within CHAT and Dewey’s idea-based social constructivism. The purpose of the text is to discuss and examine how ideas in these two theories guide educational research conducted within the framework (...) of these two approaches. Furthermore, the article aims to contribute to the discussion on CHAT and Dewey’s theory. Sources of evidence: Ideas based on Vygotsky’s theories, represented mainly by James Wertsch, Michael Cole, Barbara Rogoff and Yrjö Engeström, and Dewey’s ideas, are examined and discussed in relation to educational research. Furthermore, statements made by Mietinnen, Garrison and Rorty are taken into account in the discussion on the two outlined theories. Main argument: When CHAT and Dewey’s theory guide researchers in their work, they have to take the context or situation into consideration. Artefacts are treated as part of this context, and therefore have to be a focal point of the research. In educational research the classroom and the teacher are also central parts of the learning environment or context. The teacher is the one to form the learning environment in which the pupils think and act, and therefore, the teacher’s role in the classroom is important. If researchers are to manage to focus on pupils’ learning, they must direct their research focus both on the teacher as an organizer of the activities and on the collaborating and supporting processes between the teacher and the pupils, and between the pupils. This means that the research focus has to include both activity and dialogue, which includes processes in all their complexity. Conclusions: Mediating artefacts play a central role both in CHAT and Dewey’s theory. If the researcher is to ascertain what the pupils learn when using specific artefacts, he or she will have to study the activities or processes within which these learning aids are used. This indicates that the researcher has to study learning processes in progress. Garrison states that Dewey’s approach is a philosophy of cultural development. Miettinen finds that Dewey’s theory does not serve as the foundation for both historical and cultural analyses of action. I disagree with Rorty and Mietinnen, and rather follow Garrison’s lead. In both theories, social, cultural and historical factors are, in my opinion, viewed as decisive factors intertwined in what happens here and now. Therefore the setting that frames the activity with its social, cultural and historical aspects also has to be brought into focus in one’s research activity. (shrink)