Reach and speed of judgment propagation in the laboratory

TL;DR

This study introduces a novel laboratory method to examine how judgments propagate through social chains, revealing limited reach and exponential decay in propagation speed, influenced by information distortion and error overweighting.

Contribution

The paper presents a new experimental design that allows precise study of judgment propagation, overcoming previous confounding factors and providing detailed insights into social contagion dynamics.

Findings

Judgment propagation rarely exceeds 3-4 social degrees of separation.

Propagation speed decays exponentially with social distance.

Information distortion and error overweighting hinder judgment spread.

Abstract

In recent years, a large body of research has demonstrated that judgments and behaviors can propagate from person to person. Phenomena as diverse as political mobilization, health practices, altruism, and emotional states exhibit similar dynamics of social contagion. The precise mechanisms of judgment propagation are not well understood, however, because it is difficult to control for confounding factors such as homophily or dynamic network structures. We introduce a novel experimental design that renders possible the stringent study of judgment propagation. In this design, experimental chains of individuals can revise their initial judgment in a visual perception task after observing a predecessor's judgment. The positioning of a very good performer at the top of a chain created a performance gap, which triggered waves of judgment propagation down the chain. We evaluated the dynamics of judgment propagation experimentally. Despite strong social influence within pairs of individuals, the reach of judgment propagation across a chain rarely exceeded a social distance of three to four degrees of separation. Furthermore, computer simulations showed that the speed of judgment propagation decayed exponentially with the social distance from the source. We show that information distortion and the overweighting of other people's errors are two individual-level mechanisms hindering judgment propagation at the scale of the chain. Our results contribute to the understanding of social contagion processes, and our experimental method offers numerous new opportunities to study judgment propagation in the laboratory.