  Although affective expressions of individuals have been extensively studied
using social media, research has primarily focused on the Western context.
There are substantial differences among cultures that contribute to their
affective expressions. This paper examines the differences between Twitter (X)
in the United States and Sina Weibo posts in China on two primary dimensions of
affect - valence and arousal. We study the difference in the functional
relationship between arousal and valence (so-called V-shaped) among individuals
in the US and China and explore the associated content differences.
Furthermore, we correlate word usage and topics in both platforms to interpret
their differences. We observe that for Twitter users, the variation in
emotional intensity is less distinct between negative and positive emotions
compared to Weibo users, and there is a sharper escalation in arousal
corresponding with heightened emotions. From language features, we discover
that affective expressions are associated with personal life and feelings on
Twitter, while on Weibo such discussions are about socio-political topics in
the society. These results suggest a West-East difference in the V-shaped
relationship between valence and arousal of affective expressions on social
media influenced by content differences. Our findings have implications for
applications and theories related to cultural differences in affective
expressions.
