Here’s what Centola’s research shows actually makes change stick: - Multiple exposures. Once isn’t enough. People need to encounter the new behavior several times from different people. - Trusted messengers. It’s not about role or rank. It’s about credibility in the day-to-day. - Strong ties. Close, high-trust relationships are where change actually moves. - Visible behavior. People need to see it being done, not just hear about it. - Reinforcement over time. Real change takes repetition. One wave won’t do it.