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Updated: Jun 15, 2026
06:48
The HoneyComb Paradigm for Research on Collective Human Behavior
Published on: January 19, 2019
Cooperative behavior cascades in human social networks
James H Fowler1, Nicholas A Christakis
1Political Science Department, University of California, San Diego, La Jolla, CA 92103, USA. jhfowler@ucsd.edu
Summary
Cooperative behavior spreads through human social networks, influencing others up to three degrees away. This study experimentally demonstrates how cooperation cascades, showing a threefold increase in contributions over time.
Area of Science:
- Behavioral Economics
- Social Network Analysis
- Evolutionary Game Theory
Background:
- Theoretical models propose social networks impact cooperation evolution.
- Observational studies show behavior spread but lack causal inference due to self-selection.
- Previous experiments demonstrated costly punishment sustains cooperation.
Purpose of the Study:
- To experimentally investigate how cooperative and uncooperative behaviors spread through human social networks.
- To determine the extent and duration of behavioral influence within social networks.
- To quantify the impact of social influence on cooperation in public goods games.
Main Methods:
- Utilized data from laboratory experiments on public goods games with random group assignments.
- Constructed interaction networks to trace the spread of behaviors.
- Analyzed the influence of focal individuals' contributions on subsequent interactions.
Main Results:
- Cooperative and uncooperative behaviors spread through social networks, influencing individuals in future interactions.
- This social influence persists for multiple periods and extends up to three degrees of separation.
- Each initial contribution to the public good resulted in a threefold increase in contributions due to social influence.
Conclusions:
- Cooperative behavior experimentally demonstrated to cascade through human social networks.
- Social networks play a significant role in sustaining cooperation.
- Findings provide empirical evidence for the spread of prosocial behavior in networks.
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