Abstract

Cognitive processes, cognitive psychology tells us, unfold in our heads. In contrast, several approaches in cognitive engineering argue for a shift of unit of analysis from what is going on in the heads of operators to the workings of whole socio-technical systems. This shift is sometimes presented as part of the development of a new understanding of what cognition is and where the boundaries of cognitive systems are. Cognition, it is claimed, is not just situated or embedded, but extended and distributed in the world. My main question in this article is what the practical significance is of this framing of an expanded unit of analysis in a cognitive vocabulary. I focus on possible consequences for how cognitive engineering practitioners think about function allocation in system design, and on what the relative benefits and costs are of having a common framework and vocabulary for talking about both human and technical system components. I argue for what I call an *expansive but deflated conception of cognition*, primarily on pragmatic grounds. In addition, I claim that the important lesson of the “boundaries of cognition” debate in cognitive science is the negative claim that there is not anything special about the biological boundary of the skin and skull per se, rather than some positive claim about where the boundaries of extended or distributed cognitive systems really are. I also examine the role of the concept of cognition in the theoretical frameworks of distributed cognition, joint cognitive systems (also known as cognitive system engineering), and cognitive work analysis.