Evidence of Herding and Stubbornness in Jury Deliberations

TL;DR

This paper investigates how herding and stubbornness influence jury decision-making by analyzing jury datasets and modeling opinion dynamics, revealing that both factors significantly shape collective jury outcomes.

Contribution

It introduces a novel model incorporating increasing stubbornness and herding in jury deliberations, validated by fitting real jury data across different states and years.

Findings

Herding influences jury opinion shifts

Increasing stubbornness affects decision stability

Models with both factors best fit observed data

Abstract

We explore how the mechanics of collective decision-making, especially of jury deliberation, can be inferred from macroscopic statistics. We first hypothesize that the dynamics of competing opinions can leave a "fingerprint" in the joint distribution of final votes and time to reach a decision. We probe this hypothesis by modeling jury datasets from different states collected in different years and identifying which of the models best explains opinion dynamics in juries. In our best-fit model, individual jurors have a "herding" tendency to adopt the majority opinion of the jury, but as the amount of time they have held their current opinion increases, so too does their resistance to changing their opinion (what we call "increasing stubbornness"). By contrast, other models without increasing stubbornness, or without herding, create poorer fits to data. Our findings suggest that both stubbornness and herding play an important role in collective decision-making.