PSS4DEMOCRACY · Which Public Sphere System for Democracy?

The transition from traditional journalism to algorithm-driven digital media has intensified existing chal-lenges such as news bias, selective exposure, and polarization, which threaten democratic engagement. An optimally constructed news environment enables an informed and engaged citizenry, which forms the foundation for the socio-political interactions that take place within democracies. This project introduces Public Sphere Systems (PSS), a groundbreaking framework that reimagines how news supply can foster democratic public spheres. Building on insights from communication studies, political theory, and computer science, it operationalizes normative ideals of public spheres into algorithmic systems that disseminate news. By (i) conducting systematic literature reviews and multilingual news corpus analysis, (ii) implementing distinct PSS models that align with democratic public-sphere principles through News Recommender System (NRS) techniques, and (iii) rigorously testing these PSS models through longitudinal field experiments in diverse Western media systems (Norway, Poland, the United States, Germany), the project bridges theory and practice. Public-sphere news supply systems will be constructed, and, for the first time, their effects demonstrably evaluated.Key outcomes include open-source PSS prototypes, comprehensive performance criteria for news environ-ments, and evidence-based policy recommendations tailored to the EU Digital Services and AI Acts. These outcomes promise to reshape the relationship between technology and democracy, offering a blueprint for how media systems can be both technologically advanced and normatively aligned with societal goals.This project redefines the role of digital news environments in the 21st century. It establishes a groundbreaking path for aligning technological innovation with democratic ideals, ensuring that ideal public spheres do not remain theoretical constructs but become tangible systems for democracy.