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Review of Economic Studies Vol. 91 No. 3 2024

Dynamic Opinion Aggregation: Long-Run Stability and Disagreement

Simone Cerreia-Vioglio1; Roberto Corrao2; Giacomo Lanzani2

1 Bocconi University Milan Italy · 2 MIT , Cambridge , USA

Abstract

This article proposes a model of non-Bayesian social learning in networks that accounts for heuristics and biases in opinion aggregation. The updating rules are represented by non-linear opinion aggregators from which we extract two extreme networks capturing strong and weak links. We provide graph-theoretic conditions for these networks that characterize opinions’ convergence, consensus formation, and efficient or biased information aggregation. Under these updating rules, agents may ignore some of their neighbours’ opinions, reducing the number of effective connections and inducing long-run disagreement for finite populations. For the wisdom of the crowd in large populations, we highlight a trade-off between how connected the society is and the non-linearity of the opinion aggregator. Our framework bridges several models and phenomena in the non-Bayesian social learning literature, thereby providing a unifying approach to the field.

DOI
10.1093/restud/rdad072
Volume
91
Issue
3
Pages
1406-1447
Language
en
Sources
bibtex:phds-export.bib openalex crossref

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