Yet the study actually appears to show two different (though closely related) things: students with lower GPAs tended to have more anxiety than those with higher GPAs, and students who frequently used their phones tended to have lower GPAs.
Intriguing, but it’s uncertain exactly where correlation and causation lie: presumably, would heavy cell phone use not cause anxiety if the student still managed an A average? What about heavy phone use during semester breaks, when grades are not an issue? Is the problem simply “time spent on the phone,” or “time spent doing anything other than study or schoolwork?”
Semi-related anecdote: In 1953, science fiction writer Ray Bradbury published a short story called The Murderer, about a man considered insane by his futuristic society because he hates the constant communication devices people are expected to carry with them, to the point where he actually “murders” (destroys) some of these devices, including his “wrist radio.” The man’s science-fictional complaints include children who can call him via wrist radio at any time of day, no matter where he is, to remind him to pay their allowance, and a wife who got “hysterical” because “she had been completely out of touch with me for half a day.”
Bradbury intended his 1950s audience to be utterly appalled by the thought of a future where you could never, ever be out of reach of anyone desiring your attention. Yet only sixty years later, that’s pretty much the status quo.