Watching high-spirited videos on YouTube after a long day at work could pep you up a bit as researchers have found that people mirror the emotions of those they see online.

When a YouTuber posts a video with a generally positive tone, the audience reacts with heightened positive emotions and the same is true for other emotional states, said the study published in the journal Social Psychological and Personality Science.

"Our research is a reminder that the people we encounter online influence our everyday emotions -- being exposed to happy (or angry) people can make us more happy (or angry) ourselves," said lead author of the study Hannes Rosenbusch from Tilburg University in the Netherlands. 

For the study, the researchers examined over 2,000 video blogs, or vlogs on YouTube.

Vloggers share emotions and experiences in their videos, providing a reliable source of data.

The researchers focused on studying more popular vlogs, with a minimum of 10,000 subscribers. Some of their sample vlogs had millions of subscribers.

To measure if people watching vlogs experienced emotional contagion or homophily, the team studied words and emotions expressed by the vloggers and analyzed the emotional language of online comments. 

Being affected by others' emotions is known as "contagion" and "homophily" refers to the tendency of people seeking out others like themselves.

The researchers modelled the effect of both immediate (contagion) and sustained (homophily) emotional reactions.

They found evidence that there is both a sustained and an immediate effect that leads to YouTuber emotion correlating with audience emotion. 

"Our social life might move more and more to the online sphere, but our emotions and the way we behave towards one another will always be steered by basic psychological processes," Rosenbusch said.