Facebook users spent less time on the site even before it announced major changes to its News Feed in January.
Measures such as showing fewer viral videos cut time spent on the social network by about 5%, or roughly 50 million hours a day, in the last three months of 2017.
However, Facebook reported better than expected results despite the fall.
Chief executive Mark Zuckerberg said the priority was encouraging more personal interaction among users.
“Helping people connect is more important than maximising the time they spend on Facebook,” he said.
“We can make sure the service is good for people’s well-being and for society overall.”
In January, Facebook said it would make changes to news feeds to prioritise posts from friends and family and make content from businesses and news outlets less prominent.
The number of monthly active users rose 14% to 2.13 billion in the three months to December, although that was slightly lower growth than the previous quarter.
In the US and Canada, which generates a sizeable proportion of Facebook’s advertising revenues – the number of daily users fell about 700,000 to 184 million in the quarter.
Facebook said annual revenues soared 47% last year to more than $40bn (£28.2bn), while profits jumped 56% to nearly $16bn.
The gains came despite a $2.3bn payment triggered by recent changes to US tax law.