This study investigated how people with late bedtimes use social media. Through the analysis of emotions variation, we found that users who habitually stay up late generally expressed fewer positive emotions and negative emotions. Users who rarely stay up late mainly expressed negative emotions late at night when they stay up late, which indicated that staying up late makes them feel worse; so, they tend to express themselves on social media to cope with the negative impact of negative emotions. Positive emotions are, of course, a benefit to psychological well-being and are worth cultivating. Negative emotions could have either a positive or negative impact. Prior studies have shown that more frequent mixed emotions benefits health[27, 35]. The key is learning to cope with negative emotions rather than restraining them, which is beneficial for mental health[36, 37].
This study also conducted a demographic subgroup analysis of the emotions of the three user groups. Previous studies mainly concentrated on adolescents or specific areas. However, our study provides a nationwide survey across age, gender, and areas. The subgroup analysis was conducted to determine whether the emotional difference was consistent across gender, age, and latitude. The results suggest that the correlation between late bedtime and emotions is consistent across different ages. Male users who rarely stay up late express relatively fewer negative emotions than males in the other two groups. One possible explanation may be that males are less willing to express negative emotions because it may cause them to appear vulnerable. The results also suggest that latitude does not affect the association between late bedtimes and mood, which is consistent with previous findings.
We also observed the seasonal cycle of emotions among the three groups. The cycle amplitude of negative emotions was larger for users who stay up late more frequently, suggesting that users who habitually stay up late are more vulnerable to negative emotions. In addition, prior studies have shown that larger seasonal mood variation amplitude indicates seasonal affective disorder, which also implies the adverse effects of late bedtimes on mental health.
Thematic and posting behavior analysis was conducted to learn what kind of topics were expressed in the postings. Through content analysis, it was found that habitually late sleepers mostly mentioned entertainment news topics and reposted more messages than they originally posted, which suggests that they tend to use social media more for entertainment and getting information. Approximately 26% of their postings were talking about social pressure, which indicates that users who habitually stay up late may experience more fierce competition and greater social pressure. For users who rarely stay up late, personal life and feelings were the most mentioned theme, and they published more original postings than reposting messages. This suggests that they tend to use social media more for expressing personal emotions, which is also an explanation for why they expressed more emotions than users who habitually stay up late.
The geographical distribution of people with late bedtimes was found to be that people living in the eastern coastal regions and the Sichuan-Chongqing Region are more used to staying up late. This is similar to Weibo’s 2020 User Development Report showing that the areas with the highest coverage of Weibo users are the Sichuan-Chongqing Region and the eastern coastal regions, such as the Beijing-Tianjin-Hebei region, the Yangtze River Delta Region, Fujian Delta Region, and the Pearl River Delta Region. People in areas where social media is more popular are also used to staying up late, which indicates that social media are positively correlated with staying up late behavior. This distribution also displays the typical structural characteristics of social ecological theory. The economy of these regions is more developed than other regions in China and so people have to study more and work harder for "fear of missing out"; they also experience greater social pressure. Therefore, the time before bed may be the only time for them to deal with the stress of the day.
The time use pattern of users with late bedtimes was also observed. Compared with the daytime, the proportion of people using smart mobile devices at night has increased significantly, which shows that people tend to spend a lot of time on smart devices at night for leisure activity. Studies have shown that media use before bedtime has adverse effects on sleep and mental health, such as depressive symptoms and suicidal tendencies. Even if the light is not intense at night or late at night, our sleep quality will be affected. Smartphones are a particularly significant factor in predicting sleep problems. Smartphone addiction suggests a deficiency in self-regulation for people who delay their bedtime. Thus, restricting mobile phone usage before bedtime may be an effective behavioral intervention to prevent late bedtimes and sleep problems.
There were some limitations to our study. The tweeting time was used to infer whether people stayed up late or not, which may not be highly accurate. People who stayed up late but did not post were missed, which may result in a bias between log data and users' schedules in reality. New algorithms should be employed in future work to infer the user's accurate bed and wake time. Also, it was not possible to capture all the online behavior data from users' profile pages, such as the likes, comments, and browsing history. More relevant data should be collected in future related research.