“Successful social change is not about information. It’s about norms.”
— Damon Centola
Damon Centola's book, Change, is one of the most important books I’ve read in the past decade.
We spend enormous energy in public affairs on information. Crafting the right message, finding the right frame, deploying the right spokesperson, getting the word out. And all of that matters. But Damon Centola, a network scientist at the University of Pennsylvania, spent two decades running experiments that show the same thing over and over: getting the word out is the easy part. The hard part is getting people to act on it. And those are two completely different problems that require completely different approaches.
Information spreads through casual contact. One person tells another who tells another. Centola calls this a simple contagion. News, gossip, awareness — one exposure is enough.
But behaviour change — adopting a new technology, joining a coalition, supporting a policy, showing up at a protest — is what Centola calls a complex contagion. And complex contagions don’t spread through reach. They spread through reinforcement. People need to see multiple others in their network adopting before they’ll move. Not one influencer. Not one compelling message. Multiple independent sources, all pointing in the same direction.
That simple difference — simple vs. complex contagion — has a material impact on what we do. It means that:
- the viral model is wrong for the work that matters most.
- the influencer playbook is structurally flawed.
- awareness campaigns can backfire if they create visibility without adoption.
And it means the most important variable in any change effort isn’t the quality of the argument; it’s the architecture of the network through which that argument travels.