Washington: Do friends sport the same style in shoes or see the same movies because of their similar tastes, which is why they became friends in the first place? Or once friendship is established, do individuals influence each other to adopt similar behaviours? Social scientists don't know for sure.

They're still trying to understand the role social influence plays in spreading of trends because the real world doesn't keep track of how people acquire new items or preferences.

But the virtual world Second Life does. It is a free 3D virtual world where users can socialise, connect and create using voice and text chat.

Researchers from the University of Michigan (UM) have taken advantage of this unique information to study how "gestures" make their way through this online community.

Gestures are code snippets that Second Life avatars must acquire in order to make motions such as dancing, waving or chanting.

Roughly half of the gestures the researchers studied made their way through the virtual world friend by friend.

"We could have found that most everyone goes to the store to buy gestures, but it turns out about 50 percent of gesture transfers are between people who have declared themselves friends," said Lada Adamic, assistant professor in the UM School of Information.

"The social networks played a major role in the distribution of these assets," said Adamic, who authored a paper on the research that doctoral researcher Eytan Bakshy will present on July 7 at the Association for Computer Machinery's Conference on Electronic Conference in Stanford, California.

"There's been a high correspondence between the real world and virtual worlds," Adamic said. "We're not saying this is exactly how people share in the real world, but we believe it does have some relevance."

This study is one of the first to model social influence in a virtual world because of the rarity of having access to information about how information, assets or ideas propagate, said an UM release.

The researchers examined 130 days worth of gesture transfers in late 2008 and early 2009. They looked at 1,00,229 users and 106,499 gestures. They obtained the data from Linden Lab, the maker of Second Life.