Twitter: homophily rules online world as well as offline, research shows

Like its famous avian logo, Twitter users tend to favour birds of a feather – something which may be bad for democracy but good for the biggest flocks of like-minded people on the social media network, a new study suggests.

The study analyzed more than two million politically-committed Twitter users. Using links between these users and nearly 500,000 communications during the 2012 U.S. elections, the authors found both conservatives and liberals were exposed to a disproportionate amount of like-minded information. Moreover, like-minded tweets reached them much more quickly than those from the opposite point of view.

“When you think about it, it all sounds quite intuitive,” said Yosh Halberstam, an assistant professor with the department of economics at the University of Toronto, who co-authored the study with Brian Knight, an economist at Brown University.

The study was just published as a working paper by the National Bureau of Economic Research in the United States.

Scholars have long argued that democracy functions most effectively when voters have access to high-quality information from a diverse set of sources. A more informed electorate will be active and hold politicians accountable.

However, that ideal has always been undermined by something called “homophily” – people like to associate with others just like them, and echo their shared opinions to each other.

While social media such as Twitter may be the newest form of association and shared information, it has the same bias as the offline groups that preceded it, said Halberstam.

“Some people are going to try to use this study to say social media is just another force for ideological segregation and echo chambers,” Halberstam said. “ But it’s almost like we’ve documented something more fundamental about social networks in general than social media in particular here. It’s not social media, it’s just a fundamental truth about us as human beings.”

Just as interesting, he says, is that the study suggests – despite the effects of homophily – people who identify with large or majority groups on Twitter tend to benefit more than small or minority groups of like-minded individuals.

This is because the larger groups have more connections, and that means more interactions.

“If your identity coincides with the larger group, those interactions are going to lead you to be exposed to more information, and more information is typically going to make things better for you,” said Halberstam.

In other words, if information is power, then the majority groups get more of it, even if it is filtered through the lens of like-minded bias.

What’s more, the study confirmed earlier research suggesting social media users tend to follow a politically-diverse range of media sources, thus exposing themselves to a wide array of points of view and information.

The homophily filter only seems to apply when information is shared with other members of their social networks.

“I think it goes back to that initial message,” said Halberstam.

“We know that people need a lot of information, which we find due to homophily, minority groups do not get, and that this information should come from diverse sources, which we see due to homophily, no one gets.”