This summer, I am working in rural Virginia. Sometimes in the afternoons, after a long stretch of teaching, I will return to my room, lie down on my bed, and look out the window for ten minutes. The view is of a meadow, and beyond that a hillside, then a treeline in the distance, and the Blue Ridge Mountains beyond. It's a kind of peace I haven't known since childhood.

I'm not just being nostalgic. It turns out, there is actual science at work and a raft of data that suggests if it's joy we're after, nature is the straightest path to it.

In his new book, The Moth Snowstorm, British environmentalist Michael McCarthy writes about his experience of the sublime through the natural world. When his mother's "mind fell apart" in August of 1954, and he and his brother were taken in by an aunt, he found an antidote to his experience in a neighbor's front garden in a suburb of Liverpool. A rainbow of butterflies fluttering in a tall bush: "How could there be such living gems? And every morning in that hot but fading summer, as my mother suffered silently and my brother cried out, I ran to check on them, never tiring of watching these free-flying spirits with wings as bright as flags."

He goes on: "There can be occasions when we suddenly and involuntarily find ourselves loving the natural world with a startling intensity, in a burst of emotion which we may not fully understand, and the only word that seems to me to be appropriate for this feeling is joy."

This joy is the product of evolutionary psychology, he argues, and a link to 50,000 generations of the Pleistocene. Nature, in other words, is where we belong. "It lies buried in the genes," he writes. Five hundred generations of civilization lived in cement cities and, more recently, our days lived not with sunrise and sunset but the light of screens, cannot destroy our sense of belonging in our natural home. Nature is where we come from and evolved, he writes: "It is where the human imagination formed and took flight."

McCarthy is not alone in his thinking. David Strayer, a cognitive psychologist at the University of Utah who specializes in attention, leads students on a backpacking trip into the wilderness to experience the "three-day effect." A kind of "cleaning of the mental windshield" that occurs when we've been immersed in nature long enough, Strayer's hypothesis is nature allows the prefrontal cortex, the brain's command center, to dial down and rest and repair, like an off day between weightlifting. His research shows that time in nature doesn't only restore us, it actually improves our mental performance. After three days of backpacking, Outward Bound participants performed 50 percent better on creative problem-solving tasks.

But you don't have to commit to a long weekend in the nearest national park. A walk in the woods as short as 15-minutes can trigger measurable changes in physiology, Japanese researchers found. Looking out the window and, more incredibly, even looking at a picture of greenery reduces stress.

Researchers don't yet exactly understand why there are such profound effects when we put down our phones and re-enter the natural world, but perhaps the tinge of mystery is fitting for humanity's long relationship with reverie and the natural world. In South Korea, where more than 70 percent of the population say their jobs make them depressed, a still-popular ancient proverb might best explain the dynamic—and the cognitive effects—of humans and nature. There, body and soul are not one, but Shin to bul ee—body and soil.