# Who do we follow online? An experimental study on source clarity and social proximity in digital health communication

## TL;DR

This study shows that people are more likely to follow health advice from identifiable and socially close sources like friends or family rather than experts or AI.

## Contribution

The study experimentally demonstrates the impact of source clarity and social proximity on health advice compliance in digital environments.

## Key findings

- Messages from single specified sources increased intended compliance by 13–17 percentage points compared to diffuse sources.
- Significant others (parents, friends, colleagues) outperformed professional experts by 11–16 points in compliance.
- Source clarity and social proximity influenced compliance through credibility and reactance, not attention or comprehension.

## Abstract

Public health communication increasingly relies on digital channels where advice is encountered from diverse sources that vary in source clarity (whether the sender is perceived as clearly identifiable) and social proximity (whether the sender is perceived as relationally close). To examine how these sources shape compliance with health advice, we conducted a randomized controlled online experiment (N = 810) simulating a social media environment in which each participant viewed one weight-management post attributed to one of eight sources: parents, friends, colleagues, doctors, health influencers, news agencies, Wikipedia, or AI chatbots. We measured intended compliance and four cognitive responses: perceived credibility, psychological reactance, attention, and comprehension. Messages from single specified sources (parents, friends, colleagues, doctors, influencers, news agencies) increased intended compliance by 13–17 percentage points compared with composite diffuse sources (AI chatbots, Wikipedia). Within specified senders, significant others (parents, friends, colleagues) outperformed professional experts (doctors, influencers, news agencies) by 11–16 points. Mediation analyses showed that source clarity operated primarily through enhanced credibility, while social proximity operated through higher credibility and lower reactance; attention and comprehension did not mediate these effects. Subgroup analyses indicated stronger effects among participants with chronic conditions, higher health literacy, or behaviorally aligned daily routines. These findings suggest that, in a networked digital environment, compliance with health advice is influenced less by professional authority or aggregated information, and more by identifiable and socially close sources. The study provides evidence-based guidance for selecting sources and designing messages in public health promotion.