Online hate spreads rapidly, yet little is known about whether preventive and scalable strategies can curb it. We conducted the largest randomized controlled trial of hate speech prevention to date: a 20-week messaging campaign on X in Nigeria targeting ethnic hate. 73,136 users who had previously engaged with hate speech were randomly assigned to receive prosocial video messages from Nigerian celebrities. The campaign reduced hate content by 2.5% to 5.5% during treatment, with about 75% of the reduction persisting over the following four months. Reaching a larger share of a user's audience reduced amplification of that user's hate posts among both treated and untreated users, cutting hate reposts by over 50% for the most exposed accounts. Scalable messaging can limit online hate without removing content.

翻译：网络仇恨言论传播迅速，但关于预防性且可扩展的策略能否遏制其传播，目前所知甚少。我们开展了迄今为止规模最大的仇恨言论预防随机对照试验：在尼日利亚的X平台上针对民族仇恨进行了为期20周的信息推送活动。73,136名曾参与仇恨言论互动的用户被随机分配接收尼日利亚名人的亲社会视频信息。该活动在干预期间将仇恨内容减少了2.5%至5.5%，其中约75%的减少效果在后续四个月内持续存在。当更大比例的用户受众接触到干预信息时，无论是已处理还是未处理的用户，其仇恨帖文的传播均受到抑制，对于曝光度最高的账户，仇恨转帖减少了50%以上。可扩展的信息推送策略能够在不删除内容的情况下限制网络仇恨言论的传播。