  Social media platforms disseminate extensive volumes of online content,
including true and, in particular, false rumors. Previous literature has
studied the diffusion of offline rumors, yet more research is needed to
understand the diffusion of online rumors. In this paper, we examine the role
of lifetime and crowd effects in social media sharing behavior for true vs.
false rumors. Based on 126,301 Twitter cascades, we find that the sharing
behavior is characterized by lifetime and crowd effects that explain
differences in the spread of true as opposed to false rumors. All else equal,
we find that a longer lifetime is associated with less sharing activities, yet
the reduction in sharing is larger for false than for true rumors. Hence,
lifetime is an important determinant explaining why false rumors die out.
Furthermore, we find that the spread of false rumors is characterized by
herding tendencies (rather than collective intelligence), whereby the spread of
false rumors becomes proliferated at a larger retweet depth. These findings
explain differences in the diffusion dynamics of true and false rumors and
further offer practical implications for social media platforms.
