“The next tree is right there: It’s a link to the next webpage, a shift to the next tab,” he said. “We transfer so easily that we don’t have to use up the nuts to move on to the next one.”

So we get stuck in cycles. At what point is this considered addiction?

Not all constant phone use was considered addictive, said Steven Sussman, a professor of preventive medicine at the University of Southern California. External pressures, like a demanding job, could force people to frequently check their phones. But when people check their devices just to enhance their mood, this could be a sign of a developing problem.

Another signal of addictive behavior is becoming preoccupied with smartphone use when you should be doing something else. An even clearer indicator is what happens when the phone is taken away.

“Let’s say you go out to the mountains and you don’t get reception, so you can’t use a smartphone,” Dr. Sussman said. “Do you feel a sense of relief? Or do you feel, wow, I want to get out of these mountains — I want to use the smartphone. If you feel the latter, that’s toward the addictive direction.”

Jim Steyer, the chief executive of Common Sense Media, a nonprofit that evaluates tech products and media for families, said there needed to be a broad public awareness campaign over the dangers of walking and texting in parallel with distracted driving.

“You have distracted pedestrians and distracted drivers, so it’s the double whammy,” he said. “Tech addiction hits in both ways.”

The Debate Over the Danger

Just how dangerous is distracted walking? The answer is: It’s still unclear.

Distracted walking is a relatively new area of research. There have been few studies to show the consequences of what the behavior can lead to. And some of the studies conflict with one another.