They told me to! How social networks influence public health change

What if Taylor Swift walked up to you today and told you to try a new health product or told you to change your environmental habits to pollute less? Would you do what she says?

How about if the president of the United States personally asked you instead? Or your mother? Or your best friend?

Your social network probably influences a lot of your daily habits and behaviors without you even realizing it. This social phenomenon could actually be very important in public health as it’s never been studied in the context of creating a public health change… until now.

A team of researchers from Harvard decided to investigate how social networks influence population behavior change.

The researchers sought to assess how the introduction of either chlorine for water purification or multivitamins for nutrient deficiencies would spread in rural Honduran communities using three models for choosing influential people to dole out these interventions.

1) People were chosen based on the amount of times someone wrote their name because they were deemed as popular or influential (indegree group)
2) People were nominated by their friends and then researchers randomly selected from that list (nominated group)
3) Random people were chosen (random group)

These influential people were given one or both of the interventions with lots of instructions for use and comprehensive information. They were also given four vouchers to give to their friends that could be redeemed for the intervention in question.

Think of it like a tree that grows more and more branches. Taylor Swift tells you to take multivitamins and gives you a voucher for them. You go to your store and in exchange for your voucher, you get vitamins and four more tickets to give to your friends. So you tell your friends how great the vitamins are and they go get their vitamins plus four more tickets to give to their friends. See how the social network starts to grow?

But alas! The results are in! What might surprise you is that it wasn’t someone like Taylor Swift who maximized behavior change, nor was it someone like a president or any other celebrity. Also, the randomly chosen people weren’t that good at creating meaningful behavior change either. That rules out the people from groups 1 and 3. What’s left?

The people who were nominated by their friends as being influential were the most successful at creating population-wide behavior change. Yep, those are the people from group 2!

Think of it this way…

If you had written Taylor Swift as being the most influential person in your life (group 1), then she would have told all of her celebrity friends about the multivitamins, and they would have told all their celebrity friends, and the really cool multivitamins would have remained in the upper echelons of the socioeconomic ladder. Chances are, she wouldn’t have approached you, nor would have her fancy friends.

If you had nominated your best friend as being an influential person (group 2), he or she would definitely approach you about the new intervention, and he or she might have a lot of other friends in other socioeconomic tiers, and their friends might reach a variety or more networks. Way more connected! And the public health change circulates more broadly through the ranks of normal everyday citizens instead of a select few.

If a random stranger approached you to give you some new “multivitamin” pills (group 3), you might not be inclined to take them, and the public health change would stop right there, dead in its tracks.

Again, keep in mind that this was done in rural Honduran villages where access to Twitter and Facebook might be less commonplace than in New York City. This study relied on interpersonal, face-to-face communication so it’s unlikely anyone found out about water chlorination in their village through Instagram.

Tracking behavioral change through social networks on the Internet would be a whole different story, but an interesting one at that. But for this simple study, an individual’s friends were the most successful at establishing behavioral change.

This could be really beneficial for public health interventions in rural areas; however, changing the demographics such as location and population can drastically change the results of this study. As always, we need more research to know what method works best for establishing population change for new health interventions in differing areas and for different people.

But for now, take Taylor Swift for what she’s worth – good music and a pretty face. But do keep your friends close, as they’re worth more to you than you might think!

Stay healthy!

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