Tweet collection terms.

Automated social media accounts, known as bots, have been shown to spread disinformation and manipulate online discussions. We study the behavior of retweet bots on Twitter during the first impeachment of U.S. President Donald Trump. We collect over 67.7 million impeachment related tweets from 3.6 million users, along with their 53.6 million edge follower network. We find although bots represent 1% of all users, they generate over 31% of all impeachment related tweets. We also find bots share more disinformation, but use less toxic language than other users. Among supporters of the Qanon conspiracy theory, a popular disinformation campaign, bots have a prevalence near 10%. The follower network of Qanon supporters exhibits a hierarchical structure, with bots acting as central hubs surrounded by isolated humans. We quantify bot impact using the generalized harmonic influence centrality measure. We find there are a greater number of pro-Trump bots, but on a per bot basis, anti-Trump and pro-Trump bots have similar impact, while Qanon bots have less impact. This lower impact is due to the homophily of the Qanon follower network, suggesting this disinformation is spread mostly within online echo-chambers.被称为机器人账号（bots）的自动化社交媒体账号，已被证实会传播虚假信息并操纵在线讨论。本研究聚焦美国前总统唐纳德·特朗普首次弹劾期间，推特（Twitter）平台上转推机器人账号的行为特征。我们从360万用户处收集了超6770万条与弹劾相关的推文，同时获取了这些用户构成的5360万条关注者网络边数据。研究发现，尽管机器人账号仅占总用户数的1%，却生成了超31%的与弹劾相关的推文。此外我们还观察到，相较于普通用户，机器人账号会传播更多虚假信息，但所使用的有害言论更少。在热门虚假信息运动匿名者Q（Qanon）阴谋论的支持者群体中，机器人账号的占比接近10%。匿名者Q支持者的关注者网络呈现层级结构，机器人账号充当核心枢纽，周围环绕着孤立的普通用户。我们采用广义调和影响中心性指标（generalized harmonic influence centrality measure）对机器人账号的影响力进行量化。研究发现，支持特朗普的机器人账号数量更多，但单账号层面上，反特朗普与支持特朗普的机器人账号影响力相近，而匿名者Q相关机器人账号的影响力则更低。这种较低的影响力源于匿名者Q关注者网络的同质性特征，表明该虚假信息主要在在线回声室（echo-chambers）内部传播。