You go outside, you commune with nature. You feel good. That's familiar and simple enough that it hardly seems like a fruitful area for research. But in recent years, an entire field of environmental psychology has arisen in the efforts to tease out the relationship between nature outside of our heads and psychological and neurological processes inside. Proponents see this as integral to understanding how to heal ourselves – and perhaps the planet. 

These mental processes turn out to be subtle and nuanced. For instance, there's the matter of differentiating stress from mental fatigue. De-stressing is about getting away from the grind, visiting with a good friend, or watching the Tigers win a doubleheader. Mental restoration is different. It comes from a solo walk in the park, or time spent gardening. That was where we began a conversation with Raymond De Young, associate professor of environmental psychology and planning in the University of Michigan's School of Natural Resources and Environment. 

Metro Times: Words like "stress" and "tiredness" are part of our everyday vocabulary, but researchers in your field are working to make some distinctions. 

Raymond De Young: De-stressing might be compared to letting your car cool down after a long, hard ride. We can recover from stress by just taking time off work, getting a good night's sleep, or doing other physically relaxing things: going to a bar, talking with some friends, venting a little. 

But attentional fatigue needs a different kind of restoration. The mental fatigue we're talking about in our research, being tired in the head, is more like an empty gas tank. You've got to fill it up on a regular basis. We use up a part of our brain on a daily basis, and we have to restore it on a similar schedule. 

This need for regular restoration isn't a new idea. But somehow, our culture has gotten the wrong idea about how to go about doing it. We have led ourselves to think that vegging out in front of a TV, hanging out at the coffee shop or playing video games will restore our brains, but it doesn't. 

MT: Why not? 

De Young: We have to start by understanding what is fatiguing. The thing that runs down is a mental resource that directs our attention and allows us to focus on an important task while surrounded by a lot of distractions. We have to suppress these distractions in order to focus on the task at hand. Imagine you're at a meeting at a restaurant, and there is a lot of activity going on around you, but you need to focus on what the person you are meeting with is saying. To do this you have to suppress all of the background noise and movement, the conversations and music, waitstaff activity, even the meal in front of you. This suppression, inhibiting all of those competing pieces of information, is what we use our directed attention to do. 

But directed attention wears out. The resulting mental fatigue is not a bad thing, it's just the normal result of getting our work done. To remain effective we have to restore this mental resource. And the only way to restore directed attention is not to use it; let it rebuild through rest. 

If we don't restore it, a large number of things can go wrong, such as irritability and impulsivity that result in regrettable choices, impatience that has us making poor decisions, and distractibility that allows other people to have a large effect on our behavior. In short, mental fatigue reduces our ability to make and follow plans, and leads to an inability to mentally restrain impulsive thought or action.

A lot of the things that we imagine are restorative actually require us to continue using directed attention. Imagine you are going to a bar with a bunch of friends, you're having a great time, having conversations, enjoying some stories told. But if you're not careful, what you say you might easily hurt a friend's feelings, and if you say the wrong thing to the wrong person, you're in trouble. If you act too crazy they kick you out. So you still have to use your directed attention to manage your behavior. Another example of how we get things wrong is what we think "screen time" does to us. People think that while playing a video game they are vegging out and letting the brain recover. But, in fact, you are using directed attention to play the game.

MT: So if I walk down to Detroit's RiverWalk or some artificial wetland, once I'm there, the idea is then that I'm not going to be focusing on one thing, I'm going to let the whole thing envelop me. I'm not using my directed attention?

De Young: Exactly. And to understand how this works it helps to know that there's another kind of attention, called involuntary attention. It describes what happens when something catches our attention, engages our mind, without our effort. Loud noises certainly grab our attention, but nature, in a gentle way, also does that. The wind through the trees, the water flowing over the rocks, sunlight through the branches, an animal moving off in the distance, these things are aesthetically beautiful and capture our attention effortlessly. While our involuntary attention is engaged, our fatigued directed attention can restore itself. 

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