Complex versus simple contagion
Information spreads like a simple contagion where one contact suffices, but costly behaviors need reinforcement from several sources. Behavior adoption is a complex contagion.
How Behavior Spreads
6 ideas
Wide networks spread behavior better than narrow
Long-range weak ties transmit information but fail at costly behavior change. Redundant, clustered ties provide the social reinforcement that actually moves people to act.
The tipping point for social norms
Centola's experiments show a committed minority near a quarter of a group can flip an established convention. Below that threshold it is absorbed; above it, the norm cascades.
Social reinforcement drives adoption
People adopt demanding behaviors after seeing several peers do so, not just one. Multiple independent confirmations lower the perceived risk of change.
Network structure as behavioral infrastructure
How ties are arranged, not just who is connected, determines what spreads. Structure is treated as a designable lever for diffusion.
Weak-ties theory is incomplete
Granovetter's strength-of-weak-ties holds for information but misleads for behavior. Effective behavioral diffusion depends on the width and redundancy of bridges between clusters.