Sylvain Grandadam

Teens are undeniably influenced by those around them, and by what they see on social media from television to the internet. So what happens when western media infiltrates a remote island society?

The result, according to research from Harvard Medical School, is all too familiar. Scientists interested in studying the social influences contributing to eating disorders focused on a population of school girls living in Fiji, an ideal setting to tease apart the impact of television, since in some areas, only 8% of households own TVs while in the more urbanized regions, 85% of homes have owned them since they were first introduced around 1995. By comparing rates of eating disorders, a condition highly subject to social influences, among the girls, the team determined that those exposed to television were 60% more likely to display abnormal eating habits than those without such exposure. (More on Time.com: 5 New Rules for Good Health)

While not entirely surprising—previous studies have documented the adverse health impact that mass media has on body image among girls in developed nations—the data are the first to demonstrate how saturating the effects of mass media can be. The research team, led by Dr. Anne Becker, a professor of global health and social medicine at Harvard, determined that it wasn’t simply the girls with direct exposure to television in their homes that became vulnerable to eating disorders. They showed that body image impressions can be transmitted, like a virus, through a social network to affect, second hand, even those without direct exposure to western media. “Our study not only showed a second hand effect but demonstrated that this second hand effect is the exposure of interest,” says Becker. “Even among those with direct exposure, the harm from the exposure couldn’t be avoided because there may be friends and a social network that can transmit the exposure.”

That’s the idea behind an emerging body of work pioneered by Dr. Nicholas Christakis at Harvard and John Fowler at University California, San Diego, which shows that emotions such as happiness and loneliness, as well as health behaviors and conditions including obesity and smoking, can propagate among a network of related people. In her study, Becker took pains to adjust for potentially confounding factors, such as the influence of tourism and exposure to western ideals through travel or relatives who have ventured abroad. Even after removing these effects, the influence of the social network on disordered eating remained. (More on TIME.com: Does Extremely Picky Eating in Adulthood Signal a Mental Disorder?)

The girls were asked questions such as whether they were happy with their body, whether they limited their eating in order to influence the shape of their body or their weight, or whether they were afraid of losing control of their eating habits. These are essentially the same questions asked of girls in western societies to identify potential eating disorders, and Becker is confident that the results suggest a strong impact of western media on body image among Fijian girls. “Our study showed the strength of social network exposure to the risk for eating disorder symptoms,” she says, “and it is particularly concerning to see a small scale indigent population undergoing a rapid social change when exposed to a western-produced risk. It’s a new hazard to their social environment, to a resource poor country that is already struggling with a high burden of chronic and infectious illnesses.” The data suggest that preventing spread of eating disorders in Fiji will be only effective if health officials address how the symptoms are being spread—via exposure to mass media and networks of friends and community members. Given how quickly the symptoms have emerged after televisions were introduced more than a decade ago, such efforts should start soon. Because the spread of eating disorders in such health-poor regions, she says, “is the last thing they need.”

More on TIME.com:

Study: Online Communities Encourage Eating Disorders

Family-Focused Therapy Works Better for Teens with Eating Disorders

Marie Claire Blogger Grossed Out By Obese TV Lovers