How do people think about the causes and consequences of environmental problems such as climate change? People are both the cause of and the solution to our most pressing sustainability challenges. I study how individuals and groups mentally represent complex environmental problems, and how these representations shape the decisions that drive — or hinder — sustainable change.

Karlijn van den Broek is an Assistant Professor at the Copernicus Institute of Sustainable Development, Utrecht University. As an environmental psychologist at the Copernicus Institute of Sustainable Development, I deliberately position psychology as a bridging discipline, connecting insights from sustainability science, industrial ecology, energy modelling, transition studies, and policy research. 

Mental models

My work focuses on Mental models. Mental models are people's causal understandings of how systems work: which factors matter, how they are connected, and what can be done to change them. These representations vary widely between individuals, communities, and experts — and that variation has real consequences. When people's mental models do not reflect the actual complexity of a sustainability problem, they tend to support interventions that are too narrow, too short-term, or misaligned with system dynamics. My work argues that mental models are a critical yet underutilised leverage point for behaviour change and decision-making in sustainability transitions, and I investigate how they can be measured, compared, and shifted.

M-Tool

To make this research possible at scale, I developed M-Tool, the first standardised, open-access software for eliciting and systematically comparing mental models across individuals, groups, cultures, and domains. M-Tool has been applied to challenges ranging from the energy transition and circular economy to microplastic pollution, food systems, and socio-ecological systems — and is now used in over 25 research projects worldwide.

Sustainable Behaviour Group

I lead the Sustainable Behaviour Group, the first interdisciplinary network on sustainable behaviour in the Netherlands, which brings together over 150 researchers, students, and stakeholders across universities and faculties. 

International collaboration

My research is global in scope, with a particular commitment to co-designing research with partners in the Global South. I  currently supervise four PhD students and one postdoctoral researcher, with one PhD student having completed.