Complex Contagion of Campaign Donations

TL;DR

This paper analyzes how campaign donations spread among elites through social networks, revealing that diverse social exposure increases donations and that early donor independence predicts overall campaign fundraising.

Contribution

It introduces the concept of independent reinforcement contagion in political donations and highlights the importance of targeting multiple communities in campaigns.

Findings

Donation diffusion is driven by independent reinforcement contagion.

Cross-cutting exposure slightly reduces donation likelihood.

Early donor independence predicts total campaign funds.

Abstract

Money is central in US politics, and most campaign contributions stem from a tiny, wealthy elite. Like other political acts, campaign donations are known to be socially contagious. We study how campaign donations diffuse through a network of more than 50 000 elites and examine how connectivity among previous donors reinforces contagion. We find that the diffusion of donations is driven by independent reinforcement contagion: people are more likely to donate when exposed to donors from different social groups than when they are exposed to equally many donors from the same group. Counter-intuitively, being exposed to one side may increase donations to the other side. Although the effect is weak, simultaneous cross-cutting exposure makes donation somewhat less likely. Finally, the independence of donors in the beginning of a campaign predicts the amount of money that is raised throughout a campaign. We theorize that people infer population-wide estimates from their local observations, with elites assessing the viability of candidates, possibly opposing candidates in response to local support. Our findings suggest that theories of complex contagions need refinement and that political campaigns should target multiple communities.