The rapid expansion of social media over the past two decades has fundamentally reshaped how individuals communicate, share, and respond to one another. Among its most distinctive features is the capacity for instantaneous, real-time interaction that takes place while content is being consumed. This immediacy has not only accelerated but also complicated how emotions are expressed, perceived, and ultimately translated into human behaviour. Yet, despite the centrality of these dynamics to contemporary digital culture, the specific mechanisms through which emotions are transmitted between users—and how these emotional exchanges become tied to tangible viewer responses—remain insufficiently understood. This gap in understanding is particularly evident in digital environments where video content and live viewer comments are synchronised, creating unique conditions for emotional expression and contagion.

To address this gap, the study was guided by the Emotions as Social Information (EASI) theory, a framework which posits that emotional expressions serve as crucial social signals that shape others’ cognitions and behaviours. Building on this perspective, the research team undertook an empirical investigation that centred on the analysis of more than 50,000 barrage comments. Barrage comments are a distinctive form of online interaction: short, rapid-fire messages that appear directly on the video screen at the moment viewers post them, thereby creating a layered, communal viewing experience. The dataset for this research was drawn from a single promotional video, produced in collaboration with a commercial partner and subsequently posted on the Chinese video-sharing platform Bilibili, one of the most influential hubs of youth-oriented online culture in China.

By combining emotion analysis with advanced statistical modelling techniques, the researchers examined the extent to which viewers’ expressed emotions were associated with consumer-related behaviours. These behaviours encompassed both personal decisions, such as the intention to purchase the featured product, and interpersonal actions, such as the imitation of other viewers’ comments or behaviours. In doing so, the study paid particular attention to the dual dimensions of repetition: viewers repeating their own earlier actions on the one hand, and engaging in mimicry of others’ comments on the other. This dual focus allowed the team to capture both the individual and collective facets of behaviour that emerge in the synchronised comment-video environment.

The results provided compelling evidence of the power of emotional expression within this interactive format. Specifically, positive emotional comments were strongly associated with greater purchasing intent, highlighting the persuasive role of shared enthusiasm and positivity in shaping consumer behaviour. Beyond this, the study documented notable patterns of imitative behaviour. In certain scenes of the promotional video, waves of viewers echoed or reproduced others’ comments, demonstrating a synchronised form of collective mimicry. This finding suggests the presence of real-time emotional contagion, whereby expressions of emotion are not only observed but actively replicated, thereby reinforcing a shared affective atmosphere.

At the same time, the findings revealed more nuanced dynamics that complicate a straightforward account of emotion-behaviour relationships. For instance, repeated viewing of the same video exhibited only a weak correlation with the emotions expressed in comments, indicating that habitual engagement or repeated exposure operates differently from immediate emotional expression. This subtlety underscores the need to distinguish between diverse forms of user behaviour, since not all actions—whether revisiting content or participating in real-time commentary—carry the same emotional weight or implications for consumer decision-making.

Taken together, the study demonstrates that the synchronisation of video and barrage comments provides a fertile context for the transmission and amplification of emotions, shaping both personal purchasing intentions and collective imitative behaviours. It highlights how the interplay of individual expression and group dynamics can generate powerful cascades of affect, while also pointing to the limits of this influence in cases where behaviour is more routine or less emotionally charged. In doing so, the research advances our understanding of how emotions function as social information in digital environments, offering new insights into the mechanisms by which online interactions shape consumer culture and collective behaviour in the age of real-time media.

More information: Qiao Wang et al, Dynamic analysis of barrage comments on sentimental influence and behavior, Scientific Reports. DOI: 10.1038/s41598-025-12286-y

Journal information: Scientific Reports Provided by University of Tsukuba