[Your kids think you’re too addicted to your phone.]

Perhaps most intriguing, the paper presented color-coded graphs of the digital threads of 30 college students, monitored over four days. The graphs revealed wide differences in what people used their screens for, as well as in their patterns of switching from one kind of activity, like email, to another, such as entertainment or news. Some people sprinkle brief periods of work between huge chunks of streaming movies and YouTube, for instance; others appear to be bouncing between email, work and news sites compulsively.

These patterns can vary day to day, of course, for any of us. The deeper question for researchers, and one that they have not had an easy way to study, is how these shifting patterns shape daily experience. The most commonly cited downside of excessive screen time is low mood, or depression. In a recent study, researchers led by Johannes Eichstaedt of the University of Pennsylvania examined (with permission) the Facebook activity of 114 people diagnosed with depression. Using machine-learning algorithms, the team analyzed the content of the users’ posts from the months and years before receiving the diagnosis, and compared these to the posts of similar people who did not go on to develop depression.

The analysis found differences in how frequently certain kinds of words appeared. For instance, people who later received a depression diagnosis talked about themselves on Facebook measurably more often than people who did not develop the mood problem. The analysis, while small by big-data standards, was the first to link to diagnoses in medical records, and it solidified previous correlations between online language content and low moods.

“This is a well-documented process, that suffering generally contracts focus on the self, whereas mental well-being extends focus beyond the self,” Dr. Eichstaedt said.

The researchers found that, by analyzing Facebook language in this way, they could predict whether a person was on their way to being diagnosed with depression about 70 percent of the time. “That’s about the rate you get with clinical questionnaires, and we haven’t been able to do better so far,” he said.

Incorporating screenomes from even a sample of people who became depressed would put the Facebook data in a far richer context, and possibly clarify whether online experience indeed lowered people’s moods — and why. It might also reveal shared patterns of use in those who recover ed from depression.

The link between screen time and personality is another area of intense interest for researchers. In a 2015 study, Dar Meshi , a cognitive neuroscientist at Freie University in Berlin, led a group of researchers who described the brain circuits that support the impulse to share, and which are likely linked to levels of social media use.