The level of ecological degradation caused by human activities now presents such a risk of global instability that we have no choice but to rethink in depth the way our modern societies are organized. This requires not only transforming our lifestyles but also reassessing the structure of our sociotechnical systems and our spatial planning strategies. Doing so requires that the actors of sustainable development take into account in their reasoning and decision-making the human dimension, along with the social dynamics, underlying these complex challenges. Our goal with the ACTE Lab initiative in France is to research how cognitive science can facilitate deep and just transitions. I will illustrate through the projects we’re currently conducting how the behavioral approach could be used to develop more accurate and efficient strategies to bring about the change that is needed at all levels of our collective organization.