// NATURE NEWS — SPAZIO & SCIENZA
Educational intervention can rewire village social networks
Nature
(2026) Cite this article
Social networks shape behaviour, affect information dissemination and undergird collective action. And they can be exploited in the design of interventions in these domains1,2,3,4,5,6,7. Although social networks obey fundamental principles, such as the degree distribution8,9, they can nevertheless evolve as ties form and break. Here, through a randomized controlled trial involving a total of 8,331 people in 110 remote Honduran villages, we evaluate the secondary effects of a 22-month public-health intervention1 on pre-existing social-network structure. We used a design in which a varying fraction of village households received the intervention, and villages in which no one received the intervention were used as the primary reference group. In ‘low-dosage’ villages (in which 5–30% of households received the intervention), people who received the intervention tended to sever ties with untreated individuals to whom they previously went for health advice. Conversely, in high-dosage villages (50–100%), treated individuals increased their ties. These average changes are explained mainly by tie dynamics; that is, treated–treated pairs persist and form new links, whereas treated–untreated ties dissolve. A mediation analysis indicates that absorption of health information increases the likelihood of tie formation and persistence. The rewiring patterns generally lasted for three years after the intervention ceased. Moreover, although the intervention delivered health information, it reshaped friendship and financial ties, not just health-advice connections. In aggregate, the introduction of a new information regime acted as a kind of social institution, rewiring individuals’ connections even though the overall degree distribution of village-wide networks remained relatively stable.
In many small-scale traditional or rural societies, social connections provide key benefits that would typically be available from formal institutions in large-scale or more developed societies10,11. In such environments, people rely on their friends and family for loans, rather than on banks; for security, rather than on police or courts; and for health care, rather than on doctors or clinics. For instance, in addition to seeking information from providers in the formal health-care sector, women might turn to their social networks (for example, to older female friends or relatives residing in their village) for information about, and assistance with, the delivery and care of newborns.
This raises an important issue, which is that if formal health care or official sources of health information were to be made available, and to be used, one motivation that people had for maintaining social connections to people who previously filled such a need might fall away. That is, the introduction of formal health-care institutions (which might take the form of, for example, monthly educational sessions offered by visiting outsiders) might modify or replace traditional close-knit social connections, leading to potential declines in face-to-face interactions or to a rewiring of social ties within the population. People who previously relied on friends and kin for health information might cut ties to some of their contacts or form new ties to people who are newly in possession of the information provided by the visiting health-care workers.
When formal institutions are present, in other words, an individual might turn for information and assistance to different community members who have been invested with a possibly new role by the formal institution, even if the individual’s number of connections stays the same. Indeed, many public-health and development initiatives that are ostensibly of a purely informational nature might be inadvertently rewiring social connection in locales around the world, for better or worse. Here, we sought to quantify such possible changes in several ways using data from a large-sc