PhD researcher in political psychology, University of Amsterdam

I am a PhD candidate at the University of Amsterdam (Amsterdam School of Communication Research). My PhD is part of the MSCA doctoral network Interdisciplinary Perspectives on the Politics of Adolescence and Democracy (IP-PAD), and I am affiliated with the Hot Politics Lab and the Center for Politics and Communication.
My research focuses mainly on affective polarization. I explore how it can be measured within multiparty systems, and I aim to connect political science’s understanding of affective polarization with psychological theories of affect, refining both theoretical frameworks and measurement tools to better capture its affective nature. I also investigate how affective polarization develops during adolescence, seeking to understand its origins and to address concerns about increasing polarization among younger generations. I am also interested in the implications of (affective) polarization for political behavior and democratic attitudes, as well as efforts to reduce it.
Before my PhD, I earned a Bachelor’s and Master’s degree in Psychology at the University of Heidelberg (Germany) and spent a year as a graduate exchange student at Cornell University (USA).
Schumacher, G., Kasper, J., Van der Velden, M. A. C. G., Zaslove, M., Rooduijn, M., & Bakker, B. N. (under review). Strengthening democracy with interventions: A conceptual replication of a megastudy in the Netherlands. Preprint
Kasper, J., Schumacher, G., te Brinke, L., Crone, E., & Bakker, B. N. (under review). Coming of age in polarized times: Affective polarization across adolescence. Preprint
Kasper, J., Bakker, B. N., Lelkes, Y., & Schumacher, G. (under review). Beyond valence: Arousal as a core dimension of affective polarization. Preprint
Kasper, J., Schumacher, G., & Bakker, B. N. (2025). Establishing the construct and predictive validity of brief measures of affective polarization. European Journal of Political Research. DOI
Kasper, J., & Gilovich, T. (2025). Do people prefer to share political information that boosts their ingroup or derogates the outgroup? Journal of Experimental Psychology: General. DOI