Pareto-Improvement-Driven Opinion Dynamics Explaining the Emergence of Pluralistic Ignorance
Yuheng Luo, Chuanzhe Zhang, Qingsong Liu, Hai Zhu, Wenjun Mei
TL;DR
The paper introduces a Pareto-improvement-driven (PID) multi-objective opinion dynamics model that represents two nonexchangeable motivations—social pressure and cognitive dissonance—as separate costs and updates opinions via Pareto improvements. It provides a rigorous equilibrium and convergence analysis, deriving necessary and sufficient conditions for consensus and for the prevalence or emergence of truth, and it identifies cohesive sets as a central structural determinant. Through simulations on Erdős–Rényi and Watts–Strogatz networks, it reveals nontrivial effects of network density and clustering on pluralistic ignorance, showing that moderately sparse, well-mixed networks best promote truthful consensus and mitigate false consensus. The results highlight the critical role of strictly cohesive sets and offer an initial-seeding strategy to guarantee consensus on truth, yielding actionable sociological insights into how network structure shapes collective learning.
Abstract
Opinion dynamics has recently been modeled from a game-theoretic perspective, where opinion updates are captured by individuals' cost functions representing their motivations. Conventional formulations aggregate multiple motivations into a single objective, implicitly assuming that these motivations are interchangeable. This paper challenges that assumption and proposes an opinion dynamics model grounded in a multi-objective game framework. In the proposed model, each individual experiences two distinct costs: social pressure from disagreement with others and cognitive dissonance from deviation from the perceived truth. Opinion updates are modeled as Pareto improvements between these two costs. This fwork provides a parsimonious explanation for the emergence of pluralistic ignorance, where individuals may agree on something untrue even though they all know the underlying truth. We analytically characterize the model, derive conditions for the emrameergence and prevalence of the truth, and propose an initial-seeding strategy that ensures consensus on truth. Numerical simulations are conducted on how network density and clustering affect the expression of truth. Both theoretical and numerical results lead to clear and non-trivial sociological insights. For example, no network structure guarantees truthful consensus if no one initially express the truth; moderately sparse but well-mixed networks best mitigate pluralistic ignorance.
