Weibo provides its users a cyber platform to share opinions and show their emotions towards issues at home and abroad. In the process, massive amounts of data are made, and becomes the raw material for sentiment analysis. Previous studies in related fields of computer science and communication focused mainly on developing better sentiment analysis techniques to analyze basic emotions. To add a new perspective, this paper focused on studying the moral emotions expressed toward the “7.23 Wenzhou Train Collision” by Chinese netizens on Weibo. In particular, we analyzed the frequencies of different moral emotions expressed, and related them to the temporal occurrence of different moral events (e.g., statements made by the authority or victims that have moral implications) in the aftermath of the collision, and how different patterns of moral emotions were expressed by different groups including male and female, VIP and non-VIP users.

First of all, we utilized Weibo API to obtain the Weibo Dataset. Specifically, from July 23rd, 2011 to September 1st, 2011 we used several developer IDs to keep grabbing the public timeline, which is a sample of the real time tweets. Then we used a set of keywords to filter out irrelevant tweets and obtain tweets related to the train accident happened on July 23rd. In total, we got 94,562 valid tweets, among which 21,466 tweets contain users’ information. Secondly, we conducted sentiment classification using K-Nearest Neighbor approach based on the training data labeled by 41 experts. After that, all tweets in the dataset were assigned scores from 0 to 5 for each categories of sentiment and the sentiment evolution chart was drawn. Thirdly, we related the knee points of the chart to the moral events happened during the aftermath of the train collision to identify which emotion was evoked by a certain event. Fourthly, we conducted logistic regression and Robust Maximum Likelihood Estimator (MLR) to analyze the difference of emotional expression among different groups.

Results indicated that (1) people showed strong moral anger, contempt, disgust, compassion and love during the moral events that happened in the aftermath of the train accident. (2) The pattern of associations between the moral events and the moral emotions supported the Moral Foundation Theory. (3) Men, in comparison to women, were more likely to express anger, disgust and contempt with higher intensity while women exceeded men at both the likelihood and intensity in expressing compassion and love. (4) For compassion and love, organizational VIP users showed higher likelihood as well as intensity than individual VIP users and non-VIP users. But when it came to anger, disgust and contempt, individual VIP users showed higher likelihood and emotional intensity than non-VIP users and organizational VIP users.