Something that can be spread. Infectious diseases, information, innovation, etc.

There can be many types of contagions. Many diseases require only one contact (simple contagion). However many behaviors require multiple exposures, or social affirmation (Complex contagion).

A recent study argues that interacting contagions are indistinguishable from social reinforcement2.

Check out Jonah Berger‘s research on the ‘virality’ of contagions.

Voting behavior is contagious1.


Talks and lectures


Statistical test

  1. Nickerson, David W. (2008). “Is Voting Contagious? Evidence from Two Field Experiments”. American Political Science Review 102 (01). doi:10.1017/S0003055408080039. ISSN 0003-0554. 

  2. Laurent Hébert-Dufresne, Samuel V. Scarpino, Jean-Gabriel Young, Interacting contagions are indistinguishable from social reinforcement, Nature Physics, Hébert Dufresne2020macroscopic