Kostas Papaioannou is an Assistant Professor of Political Behaviour at the Department of Political Science and International Relations, University of the Peloponnese, and Principal Investigator (PI) of the research project “The Age of Post-Truth: Political Parties and Conspiracy Theories” (CONSPIRAPOP), funded by the Hellenic Foundation for Research and Innovation (HFRI/ELIDEK, 2026–2028). This research project builds on his doctoral dissertation (“An Arena of Angry Minds? Uncovering Hidden Relationships: Conspiracy Theories, Populism and Democracy”) and examines conspiracy theories and populism in political discourse, drawing on social media data (Facebook, Instagram, X/Twitter) through a comparative analysis of European countries.

His work has been published in leading international academic journals, including Political Psychology, British Journal of Social Psychology, International Political Science Review, British Journal of Psychology, European Journal of Social Psychology, and Acta Politica, among others. He has taught and worked at universities across Europe, including the London School of Economics (UK), Utrecht University (the Netherlands), the Université libre de Bruxelles (Belgium), and Lund University (Sweden), as well as in the United States (University of California, Berkeley).

He has worked for several years as a Senior Researcher at the National Centre for Social Research (London, UK), where he led and contributed to research projects funded by the UK government on public attitudes and politics in post-Brexit Britain. These projects also involved the evaluation of public policy programmes and interventions using experimental and quasi-experimental methods, contributing to evidence-based public policy decision-making (e.g. British Social Attitudes).

He is also the elected Chair of the Early Career Committee of the International Society of Political Psychology (ISPP).