Educational intervention can rewire village social networks

What it is

Social networks shape behaviour, carry information and underpin collective action, and they can be exploited in the design of interventions. They obey fundamental principles such as the degree distribution, yet they can still evolve as ties form and break. Through a randomized controlled trial of 8,331 people in 110 remote Honduran villages, the authors evaluate the secondary effects of a 22-month public-health intervention on the social-network structure that was already there. A varying fraction of each village's households received the intervention, and villages where nobody received it served as the primary reference group. In low-dosage villages, where 5-30% of households were treated, people who received the intervention tended to sever ties with untreated individuals they had previously gone to for health advice. In high-dosage villages, 50-100%, treated individuals increased their ties. These average changes are explained mainly by tie dynamics: treated-treated pairs persist and form new links, while treated-untreated ties dissolve. A mediation analysis indicates that absorbing health information increases the likelihood of a tie forming and persisting. The rewiring patterns generally lasted 3 years after the intervention ceased, and although the intervention delivered health information, it reshaped friendship and financial ties too, not just health-advice connections. In aggregate, the authors write, a new information regime acted as a kind of social institution, rewiring individual connections even as the overall degree distribution of village-wide networks stayed relatively stable.