# Behavioral Contagion
**Entity class:** Social-science concept
**Domain:** Social psychology / collective behavior / network science
**Maturity:** Developed
## Definition
**Behavioral contagion** is the spread of observable conduct through exposure, imitation, social reinforcement, or changing perceptions of what others consider possible or legitimate. It is broader than ideology: a person may copy a tactic or performance without adopting the originating actor's complete worldview.
In terrorism research, the concept helps distinguish the diffusion of attack scripts, targets, manifestos, propaganda styles, and publicity-seeking behavior from membership in an organization. It overlaps with copycat effects and [[wiki/Stochastic Terrorism|stochastic terrorism]], but neither exposure nor imitation alone supplies a complete causal explanation.
## Relationships
- **applied to:** [[wiki/Contagion of Terrorism|Contagion of Terrorism]].
- **differs from:** [[wiki/Memetic Theory|Memetic Theory]], which centers cultural information and replication.
- **network condition:** [[wiki/Social Network Analysis|Social Network Analysis]] can test clustering and pathways.
- **countermeasure:** [[wiki/Inoculation Theory|Inoculation Theory]] and [[wiki/Prebunking|Prebunking]] address some informational mechanisms.
## Sources / Provenance
- [National Institute of Justice — Social networks and domestic radicalization](https://nij.ojp.gov/library/publications/role-social-networks-facilitating-and-preventing-domestic-radicalization-what)