From individual change to systemic change: the case of waste sorting in a disadvantaged neighborhood[Du changement individuel au changement systémique : le cas du tri des déchets en quartier prioritaire]

[Inférence] Studies aiming to change behavior in the fields of health or the environment show short term, moderate and heterogeneous results. These studies are based mainly on a linear paradigm in which a few variables, that interact little with each other, are sufficient to explain consumer behaviors. Systemic social marketing is a promising alternative that takes into account social systems, non-linear relationships between variables, and complex interactions between stakeholders. This approach is indispensable for addressing apparently insurmountable problems, such as improving waste sorting in Habitats à Loyer Modéré (HLM) located in Quartiers Prioritaires de la Politique de la Ville (QPV). Despite the importance of sorting for the circular economy and the environment, performances are particularly low in this type of housing, which has been little explored and combines several unfavorable factors. To reconstruct how the residential system influences waste sorting, interviews with several actors in addition to residents, as well as site visits, were conducted in Trappes (Yvelines, 78) in 7 HLM residences. A qualitative Causal Loop Diagram (CLD) was produced in order to visualize the feedback loop structure, as well as the levers that can be activated by the main actors in the residential system. Three feedback loops were identified around the variables of sorting, cleanliness and over-maintenance. Improving sorting notably requires the intervention of the caretaker and the Social and Urban Development Officer to develop interventions such as home advisory visits or participatory nudges. Diagnosis based on a CLD is a promising avenue for improving sorting in HLM and QPV. Impact evaluation within a systemic approach and the use of numerical simulation are two crucial avenues for research to facilitate social change beyond changes in individual behaviors.