Abstracts Seminar 25-03-2022

Saeed Badri (Tinbergen Institute, UvA), Bernd Heidergott, Ines Lindner

Interrelated dynamics of social networks and infectious disease spread

We study how the presence of bots affects the degree of misinformation and polarization in society. We study learning and opinion formation in a classical setting where agents naïvely update beliefs by repeatedly taking weighted averages of neighbors’ opinions in a social network. In particular, we analyze how bots challenge the phenomenon of the wisdom of crowds. The latter describes the empirical observation that – in absence of bots – aggregation of information in groups often results in decisions that are better than could have been made by any single member of the group. Our goal is to identify and measure the impact of bots as an obstacle to wisdom. In particular, we will identify the nature of this impact as a singularity of the ergodic projector of a Markov process. We will show how to measure this impact despite the analytical complexity of opinion formation in networks.

Mike Lees (University of Amsterdam)

Computational Models to understand School Segregation: the role of social networks in parents and children

The issue of segregation in education can be (and has been) examined from both the individual level (e.g., parent surveys, choice analysis, etc.) or from macro-level statistics (e.g., changes in segregation level, region, city or national level). The uniqueness of a complexity science approach is the ability to connect these two levels and perhaps demonstrate that seemingly innocuous changes in individual behaviour or societal context can lead to drastic change in macro level dynamics. In the compass project, working with the inspectorate of education and the city of Amsterdam, we are developing agent-based models to analyse the process of school segregation. In this talk I will describe our approach to understanding segregation and explain how social networks play a fundamental role, both in terms of parental choice and in terms of the friendships established within the classroom. I will demonstrate a model of network construction that can be used to understand the complex relationship between segregation at a school level and segregation within the classroom.