Story highlights Research shows online communities reinforce old ideas, exclude outside ones

This can facilitate the spread of 'fake news'

(CNN) On the surface, it seems like social media has the boundless potential to expand our world, connecting us to ideas and people we otherwise would never have found. However, a new study claims just the opposite: Social media actually isolates us, creating and facilitating confirmation biases and echo chambers where old -- and sometimes erroneous -- information is just regurgitated over and over again.

If it sounds bleak, it's because it kind of is.

The findings were published in the Proceedings of the National Academy of Sciences . Using data modeling, a team of researchers from Italy mapped the spread of two types of content: conspiracy theories and scientific information.

JUST WATCHED How did 'pizzagate' inspire violence? Replay More Videos ... MUST WATCH How did 'pizzagate' inspire violence? 02:08

"Our findings show that users mostly tend to select and share content related to a specific narrative and to ignore the rest. In particular, we show that social homogeneity is the primary driver of content diffusion, and one frequent result is the formation of homogeneous, polarized clusters," the paper concludes.

In other words, you and all of your friends are all sharing the same stuff, even if it's bunk, because you think alike and your tightly-defined exchange of ideas doesn't allow for anything new or challenging to flow in.

Read More