  In this study, we explore the power of group dynamics to shape the toxicity
of Twitter conversations. First, we examine how the presence of others in a
conversation can potentially diffuse Twitter users' responsibility to address a
toxic direct reply. Second, we examine whether the toxicity of the first direct
reply to a toxic tweet in conversations establishes the group norms for
subsequent replies. By doing so, we outline how bystanders and the tone of
initial responses to a toxic reply are explanatory factors which affect whether
others feel uninhibited to post their own abusive or derogatory replies. We
test this premise by analyzing a random sample of more than 156k tweets
belonging to ~9k conversations. Central to this work is the social
psychological research on the "bystander effect" documenting that the presence
of bystanders has the power to alter the dynamics of a social situation. If the
first direct reply reaffirms the divisive tone, other replies may follow suit.
We find evidence of a bystander effect, with our results showing that an
increased number of users participating in the conversation before receiving a
toxic tweet is negatively associated with the number of Twitter users who
responded to the toxic reply in a non-toxic way. We also find that the initial
responses to toxic tweets within conversations is of great importance. Posting
a toxic reply immediately after a toxic comment is negatively associated with
users posting non-toxic replies and Twitter conversations becoming increasingly
toxic.
