In an interview, Dr. Kross said that it was too early to draw hard conclusions on the psychological effects of quitting Facebook. He pointed to two recent, smaller randomized studies that found users’ moods lifted when their access to social media was restricted.¶¶“What I take away from these three papers” — the Stanford study and the two smaller ones — “is we need to know more about how and when social-media use impacts well-being, not conclude that the relationship doesn’t exist,” or is very mild, Dr. Kross said.