For the first time in three days in the wilderness, Mr. Braver is not wearing his watch. “I forgot,” he says.
It is a small thing, the kind of change many vacationers notice in themselves as they unwind and lose track of time. But for Mr. Braver and his companions, these moments lead to a question: What is happening to our brains?
Mr. Braver, a psychology professor at Washington University in St. Louis, was one of five neuroscientists on an unusual journey. They spent a week in late May in this remote area of southern Utah, rafting the San Juan River, camping on the soft banks and hiking the tributary canyons.
It was a primitive trip with a sophisticated goal: to understand how heavy use of digital devices and other technology changes how we think and behave, and how a retreat into nature might reverse those effects.
Cellphones do not work here, e-mail is inaccessible and laptops have been left behind. It is a trip into the heart of silence — increasingly rare now that people can get online even in far-flung vacation spots.
As they head down the tight curves the San Juan has carved from ancient sandstone, the travelers will, not surprisingly, unwind, sleep better and lose the nagging feeling to check for a phone in the pocket. But the significance of such changes is a matter of debate for them.
Some of the scientists say a vacation like this hardly warrants much scrutiny. But the trip’s organizer, David Strayer, a psychology professor at the University of Utah, says that studying what happens when we step away from our devices and rest our brains — in particular, how attention, memory and learning are affected — is important science.
“Attention is the holy grail,” Mr. Strayer says.
“Everything that you’re conscious of, everything you let in, everything you remember and you forget, depends on it.”
Echoing other researchers, Mr. Strayer says that understanding how attention works could help in the treatment of a host of maladies, like attention deficit disorder, schizophrenia and depression. And he says that on a day-to-day basis, too much digital stimulation can “take people who would be functioning O.K. and put them in a range where they’re not psychologically healthy.”
The quest to understand the impact on the brain of heavy technology use — at a time when such use is exploding — is still in its early stages. To Mr. Strayer, it is no less significant than when scientists investigated the effects of consuming too much meat or alcohol.
But stepping away is easier for some than others. The trip begins with a strong defense of digital connectedness, a debate that revolves around one particularly important e-mail.