Centola says that changing behaviors as a result of social network influence doesn't work so simply, though. The reason is the difference between what are called simple and complex contagions. It only takes a single contact to tell you that smoking is bad for you (simple contagion), but it will take multiple contacts to get you to quit smoking ( complex contagion), Centola says. Information can spread among the weak ties of a randomized network, but when it comes to behavior change, it's only a matter of time before there are no longer any ties that bind.
The answer, Centola found by leveraging the infrastructure of MIT's online fitness program, is to connect users to "neighbors" based on the concept of homophily, meaning "love of the same."
Users of the online fitness site were more likely to adopt new functionality-in this case, a calorie-and-exercise tracker that offered a real-time look at a user's weight-if fellow users of the same gender or similar age and body mass index were also using it.
Policy implications of these findings, says Centola, who is helping the site PatientsLikeMe analyze data on its 130,000 users, who connect with people with similar medical conditions, include providing incentives for social interactions, conducting sentiment analysis of the information that's shared to revise future messages and repeatedly messaging the people you want to join.
The last point stems from another experiment Centola conducted. In a closed, invitation-only network, users were more likely to come back the more "signals" they received indicating that others were joining the service; the "eager beavers" who joined early on, it turns out, were least likely to keep using the service.
3. Usability: Give Users Something Familiar
Getting people to use health and wellness services isn't always about gathering data every 60 seconds and providing real-time feedback on what it all means. What patients often want, notes Dr. C. Anthony Jones, chief marketing officer for Philips Healthcare's patient care and clinical informatics business group, is a seemingly "mundane" application that, for example, lets them make a doctor's appointment on their smartphone.