Amid Allegations of Bias, Facebook Explains How 'Trending Topics' Works

Facing an uproar from conservatives and even calls for a congressional inquiry from a prominent lawmaker, Facebook is going to great lengths to explain how it decides what shows up on its trending news notifications.

On Thursday, the company released a 28-page internal document that details the instructions to the humans who shepherd the "Trending Topics" feature. It's the news section you – and Facebook's 1.6 billion users world-wide — see at the top right-hand corner of Facebook on desktop or when you do a search on mobile.

What we now know is that trending topics are driven in part by an algorithm and in part by humans. A Gizmodo article this week cited anonymous former contractors from the Trending Topics team, saying that human curators sometimes passed up conservative-leaning topics in favor of more liberal ones.

The release of the internal document represents Facebook's continued pushback against bias allegations. The document was made public for the first time after being shared with The Guardian. As Trending Topics' chief said on Monday, the guidelines do not allow or advise some kind of systematic discrimination against sources with particular ideologies.

What the document shows is how people are involved in the process, sometimes "injecting" newsworthy stories and sometimes "blacklisting" stories, for example for not being a "real-world world" event or for being duplicative. This kind of role of human curators has drawn suggestions that Facebook was becoming more of a publisher — in a traditional sense, like the mainstream news media — than a perfectly neutral platform.

Facebook says it hasn't found any evidence of intentional manipulations of the Trending Topics section to suppress conservative stories, the New York Times reports. The paper outlines some big takeaways from the guidelines:

"For instance, after algorithms detect early signs of popular stories on the network, editors are asked to cross-reference potential trending topics with a list of 10 major news publications, including CNN, Fox News, The Guardian and The New York Times.

While algorithms determine the exact mix of topics displayed to each person, based on that user's past actions on Facebook, a team of people is largely responsible for the overall mix of which topics should — and more important, should not — be shown in Trending Topics."

The document did not detail the inner workings of the algorithm behind the Trending Topics, nor did it touch upon the way that the company determines what posts are deemed worthwhile to show up in someone's main feature, Newsfeed.