GLEN CANYON NATIONAL RECREATION AREA, Utah -- Todd Braver emerges from a tent nestled against the canyon wall. He has a slight tan, except for a slim pale band around his wrist.
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?