Microblogs are one of the main social networking channels by which information is spread. Millions of users repost information from microblogs and share embedded emotion at the same time. The present study employed a mimicked interface of microblog (sina Weibo) and recruited university students to investigate users' propensity to repost microblogs of positive, negative or neutral valence, and studied the neural correlates with reposting microblogs of different emotional valence. Ninety pieces of microblog messages, consisting of 30 positive, 30 negative and 30 neutral were read by 28 participants (14 males and 14 females). Their propensity to repost, valence-related neural activity, and reposting-related neural activity were recorded when they read messages and decided whether to repost them. We found reposting behavior was moderated by emotion. Participants preferred to reposting emotional microblogs relative to neutral microblogs, corresponding to amplified activity in dorsolateral prefrontal cortex (DLPFC), insula, precuneus and tempoparietal junction (TPJ), the key nodes of cognitive control, emotion, self-relevance processing and mentalizing respectively. Moreover, negative microblogs were more reposted than positive ones, corresponding to amplified activity in postcentral gyrus, superior frontal gyrus (SFG) and TPJ. Reposting negative microblogs induced increased activity in bilateral TPJ, indicating that TPJ plays a key role on decisions to propagate negative information. These findings reveal an important behavioral pattern in which negative information prevails in the transmission through microblogs, as well as the neural correlates with this process. It also provides empirical evidence of how reposting works in microblogs and how the brain is involved in social propagation of information.
Keywords: Emotion; Information propagation; Mentalizing; Microblog; Social sharing; fMRI.