Online communitarian appeals increase opposition to violent extremism.

Governments and nongovernmental organizations have implemented hundreds of countering violent extremism (CVE) programs designed to combat radicalization and reduce support for violent extremist organizations (VEOs). However, the effectiveness of these programs is rarely evaluated rigorously, providing little guidance to scholars or practitioners. We therefore pair a large-scale Facebook study (39.8 million impressions) with an online survey experiment ( N = 7 , 707 respondents) to compare the effectiveness of three brief videos designed with local partners to reduce support for violent extremism and VEOs in Bangladesh. We find that a message of communal harmony from religious authorities received greater Facebook engagement and more frequent supportive emojis than messages stating that all religions oppose terrorism or warning about the costs of terrorism. We test the robustness of these messages by randomly exposing respondents to brief footage of an antigovernment protest organized by a local VEO. Communal harmony was the only message that increased net opposition to extremism after this counter-programming was introduced. An exploratory analysis further reveals that the messages do not affect intentions to attend VEO events or share VEO messages online. Instead, they increase intentions to oppose VEOs by sharing messages or attending rallies by mainstream or antiextremist groups. These results highlight the value of communitarian appeals by religious authorities as well as the need for more experimental, multiplatform evaluations of CVE messaging that separately measure VEO support and opposition.