Although there is widespread consensus in current research that the societal dimension is a key pillar of the circular economy, its treatment and study remain limited compared to other dimensions (Scarpellini, 2022). This could be attributed to the fact that the early definitions and studies of circular economy ecosystems were dominated by the technical and biological dimensions – or flows – as depicted by the seminal butterfly diagram (MacArtuhr, 2013). It is well advocated, however, by an overwhelming proportion of the CE research community, that human-made practices of (linear) production and consumption are mainly responsible for the environmental decline and finite resource demise (Kumar et al., 2021). As such, studying the human aspects and human factors that affect the transition to circular economy is of paramount importance, should a pragmatic and actionable sustainability solution be developed.

In this paper we introduce the concept of the Human-in-the-circular-loop, HITCL. Inspired by the well-known concept of Human-in-the-Loop (HITL) in computer science which studies the need and arrangements for human intervention and control in machine learning systems, this paper introduces and elaborates the term of Human-in-the-Circular-Loop (HITCL). HITCL places the emphasis on modeling and understanding the human perception and decision-making process when interacting within a CE ecosystem. More specifically, the scope of the HITCL concept covers those human aspects that can potentially influence circular economy loops. It studies human decision making in ways that can either hinder or support the transition toward a circular economy.