Mark Zuckerberg wants Facebook to focus on “meaningful interaction.” He spoke to New York Time about the sweeping changes being made to its News Feed.

SAN FRANCISCO —Facebook introduced sweeping changes to the kinds of posts, videos and photos that its more than two billion members will see most, saying on Thursday that it would prioritize what their friends and family share and comment on while de-emphasizing content from publishers and brands.

The shift is the most significant overhaul in years to Facebook’s News Feed, the cascading screen of content that people typically see when they log into the social network. Over the next few weeks, users will begin seeing fewer viral videos and news articles posted by media companies. Instead, Facebook will highlight posts between friends — for example, a photo of your dog, or a status update that many of your friends have commented on or liked.

The changes are intended to maximize the amount of content with “meaningful interaction” that people consume on Facebook, Mark Zuckerberg, the company’s chief executive, said in an interview. Facebook, he said, had closely studied what kinds of posts had stressed or harmed users. The social network wants to reduce what Mr. Zuckerberg called “passive content” — videos and articles that ask little more of the viewer than to sit back and watch or read — so that users’ time on the site was well spent.

“We want to make sure that our products are not just fun, but are good for people,” Mr. Zuckerberg said. “We need to refocus the system.”

Thursday’s changes raise questions of whether people may end up seeing more content that reinforces their own ideologies if they end up frequently interacting with posts and videos that reflect the similar views of their friends or family. And bogus news may still spread — if a relative or friend posts a link with an inaccurate news article that is widely commented on, that post will still be prominently displayed.

The goal of the overhaul, ultimately, is for something less quantifiable that may be difficult to achieve: Facebook wants people to feel positive, rather than negative, after visiting.

“When people are engaging with people they’re close to, it’s more meaningful, more fulfilling,” said David Ginsberg, director of research at Facebook. “It’s good for your well-being.”

Facebook has been under fire for months over what it shows people and whether its site has negatively influenced millions of its users. The company has been dogged by questions about how its algorithms may have prioritized misleading news and misinformation in News Feeds, influencing the 2016 American presidential election as well as political discourse in many countries. Last year, Facebook disclosed that Russian agents had used the social network to spread divisive and inflammatory posts and ads to polarize the American electorate.

The repercussions from Facebook’s changes will almost certainly be far-reaching. Publishers, nonprofits, small business and many other groups rely on the social network to reach people, so de-emphasizing their posts will most likely hurt them. Adam Mosseri, vice president of product management at Facebook, who is responsible for running the News Feed, acknowledged that “there will be anxiety” from partners and publishers who often complain about the constantly shifting goal posts of what will be shown across the network.

The change may also work against Facebook’s immediate business interests. The company has long pushed users to spend more time on the social network. With different, less viral types of content surfacing more often,

After the 2016 election, for instance, Mr. Zuckerberg initially shrugged off qualms about Facebook’s effect on the outcome, even as outsiders pointed to the proliferation of fake news stories on the site that had attacked Hillary Clinton. Mr. Zuckerberg later said he had been too hasty and dismissive of the concerns. More recently, he began signaling that Facebook was rethinking what it shows people on the site.

Last week, he posted on Facebook about his goals for 2018, including “making sure that time spent on Facebook is time well spent” and adding that “this will be a serious year of self-improvement and I’m looking forward to learning from working to fix our issues together.”

On Thursday, he said many of the discussions about Facebook’s responsibilities had prompted the company “to get a better handle on some of the negative things that could happen in the system.”