The Sledgehammer

Warning! Contagious Ideas Spreading

August 15, 2023

We know how viruses spread. But is that truly the same way that ideas go “viral”?

It’s a satisfying narrative to believe:

  • Person A has a belief about a product, a band, a social movement ➡️
  • Person A exposes Persons B, C, and D to that idea ➡️
  • B, C, and D now possess that idea ➡️
  • B, C, and D each share the idea with Persons E through Z ➡️
  • Virality unlocked 🎇

But — it’s not that simple. What we really have to think about are two things: the kinds of ideas that are being spread and the kinds of networks they’re spreading in.

Sure, for some types of ideas — i.e. “simple contagions” — the virus analogy might work. Think of things like listening to a new song, sharing a meme, or maybe joining in on a new TikTok trend. Those are beliefs and actions that usually take relatively little effort, especially the ones that are already a little bit familiar to us. Take the “ice bucket” challenge for instance. With only a bucket of ice water and a willingness to get wet, over 17 million people displayed their support of raising money and awareness for ALS.

Damon Centola, a sociologist at the University of Pennsylvania, says that simple contagions such as this are “things that make sense to us intuitively. And so when we see a new one, it’s not a lot of work, emotionally or cognitively or any other way, to just adopt it and pass it on. It just seems normal.” The passing of the idea is like a firework — it happens once, quickly, but that’s enough to make it spread. A lot like transmitting a contagious virus.

In the case of the “ice bucket” challenge, people of all ages, political parties, and celebrity statuses were quick to jump on board to support an indisputably good cause. The viral videos fired off like the grand finale of a 4th of July show. And while that’s all well and good, what happens when the idea is something more substantial, like social justice or changing beliefs about health behaviors?

Centola describes these ideas as “complex contagions” — which spread more like a fishing net. When we are presented with an idea that is unfamiliar or might make us uncomfortable at first, seeing one person advocating for it isn’t enough to convince us that we should do it too.

We require a fishing net of connection points, redundancies, and repetition. For a complex contagion, we need to be convinced.

Centola cites a study of a Human Rights Campaign Facebook initiative from 2013 as a perfect example. The campaign involved changing your profile pic to a pink and red equals sign to show solidarity. And while it seemed like everyone was rushing to do it, researchers found that before someone joined in, they needed to see multiple different people from their network do it first, providing “social proof” that it was an acceptable behavior.


The Human Rights Campaign’s Facebook page, including the red equals sign and a collage of its variations. (Human Rights Campaign/Facebook). Image Credit: The Observer.

A more recent example you might remember is #BlackoutTuesday, where millions of Instagram users posted black squares in solidarity with the music industry blackout and overall support of an even bigger complex contagion—the Black Lives Matter Movement. The rise of support for BLM included several years’ worth of significant tipping points, social coordination, and a growing number of touch points among social networks.


Music stars posted black squares on their Instagram accounts as part of #blackouttuesday. Image Credit: The New York Times.

To increase its reach and showcase the recurring patterns of injustice, activist groups created a fishing net by engaging directly with mainstream media, other social groups, and formerly unconcerned citizens. In building these bridges and strengthening ties, the media coverage and national conversation transformed into identifying police violence and citing repeated tragedies as the core message of the Black Lives Matter Movement.

In solidifying his theory of simple and complex contagions, Centola performed his own study surrounding the adoption of health technology. He created two groups to spread the offer to sign up for an online health community: one was a “firework” group and one was a “fishing net” group. At the end of the study, he discovered that while information in the fishing net group spread much more slowly, it was considerably more effective in getting people signed up to participate in the program.

So what do we do with this information? Since we’re in the business of driving behavior change, these concepts help us better understand what we’re asking our customers to do. The next time you need a customer to change their beliefs, or sign up for a program, or talk to a doctor differently, or advocate for a new treatment approach, ask yourself:

  1. What are the social costs of the idea that we are trying to spread? Is it a simple contagion that will feel relatively low risk, or is it a more complex contagion that someone needs to feel safe in order to engage with it?
  2. If it’s a more complex idea, how can we give it social proof for our customers? How do we validate the idea and show that other people like them, with similar concerns, are also in support of this idea?
  3. What kind of network do we need in order for our ideas to spread successfully? Will a firework of loose ties suffice, or does it need to be a fishing net with relatively strong and redundant social ties?

Viral ideas are perhaps the ultimate way to move audiences toward a particular action. By understanding the unique elements of simple and complex contagions, we’re able to plan the perfect spark, provide the right touch points, and ultimately cultivate the ideal environment for our catchy concepts to thrive. That means even marketers focused on health and wellness shouldn’t be afraid to spread some contagion when the occasion calls for it.

At any given time, there are hundreds of actual sledgehammers floating around the Heartbeat office and resting on shelves in Heartbeaters’ homes. To celebrate their first year on the team, each HB’er receives their very own sledge — a nod to our daily pursuit of tearing down tiresome healthcare marketing. To determine what is built in its place, we often turn to outside industries, cultural forces, and personal experiences. We eagerly share them with one another, and now we’re sharing them with you. Clear the way — here comes The Sledgehammer.