
RPA PSI Seminars
RPA PSI seminars focus on trying to understand mathematical, modelling, and empirical aspects of polarisation, segregation and inequality, and their interrelationships.
>> RPA PSI Seminar: Ben Meylahn (University of Amsterdam)
Multi-agent learning models for social dynamics | 9:30 am, 13th of February 2025
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There are many models for social dynamics. Some of these are clean and simple, others can be overly complex. With multi-agent learning I try to cut a balance: Agents have only one or two parameters, while still being sophisticated enough to learn from experience. I will illustrate this approach by discussing two models for trust dynamics, and one model for opinion dynamics.

>> RPA PSI Seminar: Han van der Maas (University of Amsterdam)
Modeling Psychological Systems with Ternary Spin Models | 9:30 am, 30th of January 2025
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In previous work in psychology, we have introduced network models as alternatives to traditional common cause models, such as the g-theory of general intelligence. For major depressive disorder and attitudinal change, we used variants of the Ising model, providing new explanations for phenomena such as sudden relapse and polarization. These theoretical insights were supported by extensive empirical research, demonstrating the successful application of network models to psychological data. However, the binary nature of the nodes in these models is a limitation, as many data sets include questions with a neutral or intermediate category (e.g., "don't know" or "not relevant"). In addition, the behavior of the Ising model is somewhat limited. Ternary spin models, such as the Blume-Capel model, offer a solution by introducing richer dynamics, including tricritical behavior, which is more consistent with various phenomena observed in clinical research, attitude studies, and intelligence research. We also discuss equivalence with existing statistical approaches (multidimensional nominal response model, IRT trees) for these data types. Finally, we present new R packages for fitting the Blume Capel model to psychological data.

>> RPA PSI Seminar: Thomas Feliciani (Politecnico di Milano)
Divided spaces and Divided Opinions | 9:30 am, 23rd of January 2025
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My work investigates whether polarized attitudes on topics like immigration are more likely to emerge in ethnically segregated or non-segregated societies. Using agent-based computer simulations, it refines theoretical understanding of polarization mechanisms and explores the conditions under which residential segregation influences these dynamics. The work also advances the methodology of agent-based modeling by addressing challenges in formalizing theories, incorporating empirical data, and scaling simulations effectively.

>> RPA PSI Seminar: Yuliia Kazmina (University of Amsterdam)
9:30 am, 16th of January 2025
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The presentation will be about the Dutch social network constructed from the CBS data (https://www.sciencedirect.com/science/article/pii/S0378873324000157) and the perceptions towards immigration (https://arxiv.org/abs/2407.06820).

>> RPA PSI Seminar: Petter Törnberg (University of Amsterdam)
Social Media and Polarization: Towards a New Paradigm | 9:30 am, 5th of December 2024
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Politics around the world appears to have entered an era of unprecedented political polarization. Scholars point to the role of social media, with influential notions such as echo chambers and filter bubbles suggesting that social media polarizes by isolating us from opposing views, making us more extreme through repeated exposure to one-sided arguments. However, while this “isolation paradigm” has long been dominant, it is questioned by mounting empirical evidence. This talk argues for the need of a new paradigm – with new theory and methods for understanding online polarization. Viewing polarization through language, the talk draws on a unique database of all posts from political parties in the world, on all social media platforms, including all the associated comments. This allows an unprecedented view into online politics. The results show that social media polarization is characterized neither by ideological isolation nor rational deliberation, but rather by community formation combined with intense intergroup conflict. Drawing on these findings, the talk outlines a new “conflict paradigm” of polarization research, drawing on scholars like Emile Durkheim, Randall Collins, and Muzafer Sherif. Social media drives polarization not by isolating us in ideological echo chambers, but by throwing us into a political war in which we are forced to take sides – thus shaping a tribalized form of political life.
