Prof. dr. Jan-Willem van Prooijen

Endowed Professor of Radicalization, Extremism, and Conspiracy Thinking

Welcome!

Prof. dr. Jan-Willem van Prooijen is a behavioral scientist who received his PhD from Leiden University in 2002, and currently holds positions in Psychology and Criminology. He works as Associate Professor of Social Psychology, and Program Director of the Psychology Bachelor, at VU Amsterdam; he is Senior Researcher at the Netherlands Institute for the Study of Crime and Law Enforcement (NSCR); and, he is Endowed Professor of Radicalization, Extremism, and Conspiracy thinking at the Department of Criminal Law and Criminology at Maastricht University. Prof. van Prooijen is interested in the dark side of human beings, particularly in the context of politics, law, and society. His research has three main thematic pillars: (1) conspiracy theories, (2) unethical behavior, and (3) radical ideologies. More details of Prof. van Prooijen’s research on these issues can be found under “research”. Prof. van Prooijen published his work in journals such as Perspectives on Psychological Science, Journal of Personality and Social Psychology, and Personality and Social Psychology Bulletin, and published various books including The Psychology of Conspiracy Theories (Routledge, 2018), The Moral Punishment Instinct (Oxford University Press, 2018), and HOAX (A. W. Bruna, 2024). He received research funding from various sources, and was in 2006 awarded the Early Career Contribution Award by the International Society for Justice Research (ISJR). He has been Associate Editor for Personality and Social Psychology Bulletin, European Journal of Social Psychology and Social Justice Research, and has been on the Editorial Board of various prestigious journals, including JPSP-IRGP and Psychological Science. He was president of ISJR from 2016 to 2018, and regularly appears in the Dutch and International media.

What’s new?

New Books and Special Issue:

Van Prooijen, J.-W. (2024). Hoax: Waarom mensen in complottheorieën geloven. Amsterdam: A. W. Bruna.

Wagner, W., Durmuşoğlu, L., Holá, B., Kroeze, R., Van Prooijen, J.-W., & Werner, W. (Eds.) (2024). Punishment in international society: Norms, justice, and punitive practices. New York, NY: Oxford University Press.

Van Prooijen, J.-W., & Imhoff, R. (2023). Conspiracy theories. Current Opinion in Psychology (Special Issue). Check it out HERE

Recent publications:

Van Prooijen, J.-W. (in press). On the subjectivity of conspiracy theory appraisals. Psychological Inquiry.

Aurelia, M., Van Prooijen, J.-W., & Van Lange, P. A. M. (in press). How do people morally judge corruption? A comparison between the Netherlands and Indonesia. European Journal of Social Psychology.

Roels, S., Begeer, S., Scheeren, A., & Van Prooijen, J.-W. (in press). Conspiracy mentality in autistic and non-autistic individuals. Cognitive Neuropsychiatry.

Mao, J., Van Prooijen, J.-W., & Van Lange, P. A. M. (in press). Conspiracy theories: Groups, ideology, and status as three distinct bases for expressions in society. Current Directions in Psychological Science.

Van Prooijen, J.-W. (in press). Pandemic conspiracy theories: Implications for health and polarization. Chapter to appear in J. Forgas (Ed.) The Psychology of False Beliefs. Oxon, UK: Routledge.

Fousiani, K., & Van Prooijen, J.-W. (in press). The link between EU identification and responses to a war between two non-EU countries over time. Scandinavian Journal of Psychology.

Zhao, Q., Van Prooijen, J.-W., & Spadaro, G. (in press). Coping capacity attenuates the effect of natural disaster risk on conspiracy beliefs. Journal of Environmental Psychology.

Bierwiaczonek, K., Van Prooijen, J.-W., Van der Linden, S., & Rottweiler, B. (in press). Conspiracy theories and violent extremism. Chapter to appear in M. Obaidi & J. Kunst (Eds.), Cambridge Handbook of the Psychology of Violent Extremism. Cambridge, UK: Cambridge University Press.

Wang, H., Van Prooijen, J.-W., & Van Lange, P. A. M. (in press). How perceived coercion polarizes unvaccinated people: The mediating role of conspiracy beliefs. Journal of Health Psychology.

Schlette, A., Van Prooijen, J.-W., Blokland, A., & Thijs, F. (in press). Information, identity, and action: The messages of the Dutch anti-vaccination community on Telegram. New Media & Society.

Zeng, Z.-X., Van Prooijen, J.-W., Guo, Y.-Y., & Van der Linden, S., & (2025). The gateway belief model: A preregistered large-scale replication in China. Journal of Environmental Psychology, 102, 102542.  

Fousiani, K., Xu, S., & Van Prooijen, J.-W. (2025). Leaders’ power construal influences malevolent creativity: The mediating role of organizational conspiracy beliefs. Journal of Occupational and Organizational Psychology, 98, e70005.

Cao, S., Van Prooijen, J.-W., & Van Vugt, M. (2025). The motivations and reputational consequences of spreading conspiracy theories. British Journal of Social Psychology, 64,  e12784.

 Xu, R., Ding, Y., Guo, Y., & Van Prooijen, J.-W. (2025). System-justifying beliefs buffer against distress during the COVID-19 pandemic. British Journal of Social Psychology, 64, e12779.

Abadi, D., Van Prooijen, J.-W., Krouwel, A. P. M., & Fischer, A. (2024). Anti-establishment sentiments: Various types of realistic and symbolic threats predict populist attitudes and conspiracy mentality. Cognition and Emotion, 38, 1246-1260.  

Acar, K., Karagiannidou, A., Olsson, A., Van Prooijen, J.-W., Balter, L. J. T., Axelsson, J., Ingvar, M., Lebedev, A. V., & Petrovic, P. (2024). Delusion proneness predicts COVID-19 vaccination behavior. Frontiers in Psychiatry, 15, 1450429.

 Papaioannou, K., Pantazi, M., & Van Prooijen, J.-W. (2024). Rejection of the status quo: Conspiracy theories and preference for alternative political systems. British Journal of Social Psychology, 63, 2077-2099.

 Van Prooijen, J.-W. (2024). Group-oriented motivations underlying conspiracy theories. Group Processes & Intergroup Relations, 27, 1050-1067.

Schlette, A., Van Prooijen, J.-W., Blokland, A., & Thijs, F. (2024). The online structure and development of posting behavior in Dutch anti-vaccination groups on Telegram. New Media & Society, 26, 4689-4710.

Dong, M., Van Prooijen, J.-W., & Van Lange, P. A. M. (2024). Status cues and moral judgment: Formal attire induces moral favoritism but not for hypocrites. Current Psychology, 43, 19247-19263.

Zhao, Q., Ma, R., Liu, Z., Wang, T., Sun, X., Van Prooijen, J.-W., Dong, M., & Yuan, Y. (2024). Why do we never have enough time? Economic inequality fuels the perception of time poverty by aggravating status anxiety. British Journal of Social Psychology, 63, 614-636.

Zeng, Z.-X., Tian, C.-Y., Mao, J.-Y., van Prooijen, J.-W., Zhang, Y., Yang, S.-L., Xie, X.-N., & Guo, Y.-Y. (2024). How does economic inequality shape conspiracy theories? Empirical evidence from China. British Journal of Social Psychology, 63, 477-498.

Van Prooijen, J.-W., & Böhm, N. (2024). Do conspiracy theories shape or rationalize vaccination hesitancy over time? Social Psychological and Personality Science, 15, 421-429.

Durmuşoğlu, L., Van Prooijen, J.-W., Wagner, W. (2024). Punishment beyond borders: Attitudes towards punishment in interpersonal and international contexts. Chapter in W. Wagner, L. Durmuşoğlu, B. Holá, R. Kroeze, J.-W. van Prooijen, & W. Werner (Eds.), Punishment in international society: Norms, justice, and punitive practices. New York, NY: Oxford University Press.

Wagner, W., Durmuşoğlu, L., Holá, B., Kroeze, R., Van Prooijen, J.-W., & Werner, W. (2024). Norm violations and punishment beyond the nation-state: Normative orders, authority, and conflict in international society. Chapter in W. Wagner, L. Durmuşoğlu, B. Holá, R. Kroeze, J.-W. van Prooijen, & W. Werner (Eds.), Punishment in international society: Norms, justice, and punitive practices. New York, NY: Oxford University Press.

Van Sintemaartensdijk, I., Van Gelder, J.-L., Van Prooijen, J.-W., Nee, C., Otte, M., & Van Lange, P. A. M. (2024). Assessing the deterrent effect of symbolic guardianship through neighbourhood watch signs and police signs: A virtual reality study. Psychology, Crime, and Law, 30, 1-21.

Other news from Prof. van Prooijen's research group:

In September 2024, Zhaoquan Yu has started with her PhD project on the psychology of punishment at the department of Experimental and Applied Psychology at VU Amsterdam. She is being supported by a CSC scholarship. Her supervisors are Prof. van Prooijen and Prof. van Lange.

In June 2024, Prof. van Prooijen received his SKO (Senior University Teaching Qualification) — an educational program at Dutch universities for teaching program management.