Negative ties offset complex contagion effect on malaria preventive measure adoption in a hard-to-reach population

Interpersonal influence within social networks plays a central role in the diffusion of health behaviors, with trusted peers and opinion leaders often providing the social reinforcement necessary for adoption in contexts where legitimacy or trust is limited. However, the countervailing role of negative ties—characterized by dislike, mistrust or conflict—remains understudied. This study examines how negative ties can offset positive peer effects in the adoption of a malaria preventive measure—an insecticidal cream—in a hard-to-reach village in Meghalaya, India. We analyzed the adoption process using sociocentric signed network data collected from 102 villagers. Results show that on average adoption was most likely when at least three trusted peers used a cream, but that the presence of even one negative tie to an adopter reduced the probability of adoption to baseline levels, offsetting the positive influence of multiple trusted peers and of the local healthcare providers. These findings provide rare empirical evidence of behavioral distancing driven by negative contacts and highlight how negative relationships can disrupt complex contagion processes. Public health interventions designed for hard-to-reach populations warrant the incorporation of negative ties and of relationships with opinion leaders into diffusion models.