Online Peer Influences On One Another's Health Beliefs Through Peripheral Processes: A Review of Literature and Agenda for Future Research

Theoretical Background and research questions/hypothesis:  Understanding psychosocial influences on medical decision-making and health belief formation is significant to patient health, because health maintenance is dependent on evidence-based decisions. However, the validity of patient decisions has come under scrutiny as more is understood about psychosocial influences on decision-making. Additionally, Web 2.0’s increasing ability to facilitate patient-to-patient interactions may have significant effects on individual health decisions that are not yet understood. According to persuasion research, individuals frequently make snap decisions without careful consideration and are influenced by external variables.  These indirect variables include heuristic shortcuts such as "truth can be found in numbers".  Significantly, an increasing body of research has shown that peripheral cues such as commercial advertisements and marginal peer comments strongly affect individual attitudes toward health messages.  Because these snap decisions are contrary to informed patient decisions, this paper presents a review of current literature about peripheral online peer influences on medical decision-making and presents an agenda for future research.

Methods and Results (informing the conceptual analysis):  Health-influence literature associated with online peers were retrieved from PubMed, PsychInfo, Google Scholar.  Retrieved literature yielded surprising findings concerning social influences on health belief formation.  On the surface, results from psychosocial experiments highlight the growing influence of laypeople on health topics compared to health experts.  In fact, many influential works in health-influence research demonstrated that information posted by peers affected attitudes more strongly than those posted by health experts. Although these findings may be alarming for health advocates, a closer examination of findings revealed that homophily, or perceived similarity between readers and the message sources, was the single most influential factor on health attitudes-- above both source credibility and argument quality which are two other influential forces accepted in influence research. 

Conclusions:  Increasing trust in online peers and decreasing trust toward expert health information may not be the growing health communication issue, but rather, individuals simply cannot resist trusting those they perceive to be similar to themselves.  Importantly, studies revealed that homophily could also be shared between online laypeople and health experts, so differences in health expertise are probably not a permanent barrier to homophily or direct influence on health attitudes.

Implications for research and/or practice:  Professional health sites seeking to better influence individual attitudes should strongly consider framing their content to promote homophily between their sites and target audiences. Social forums will likely continue to grow as popular sources of health information due to their innately homophilic nature. In order to maintain a strong and positive voice of influence, health communicators should investigate how to promote both credibility and homophily in online communication efforts. Finally, studies investigate the influence of online health information on public health should integrate homophily and credibility factors into their framework in order to achieve a more comprehensive model for online influences on health belief formation.