Want to restore your attention span? Spend time outdoors

Taking a walk in nature for just 15 to 20 minutes can improve your concentration, even if you don't always enjoy it.

In his new 324-page book, Nature & Mind: The Science of How Nature Improves Cognitive, Physical, and Social Well-Being (Simon and Schuster), environmental neuroscientist Mark G. Berman discusses how our natural environment can help restore people's frayed, overstimulated nervous systems.

Berman, founder and director of the University of Chicago's Environmental Neuroscience Laboratory, is also a professor and chair of the University of Chicago's Department of Psychology and co-director of the Graduate Program in Computational Social Sciences.

Through research from his lab, Berman and his team have found that walking for longer periods of time—say, about 50 minutes—can significantly improve cognitive function, but the beauty is that you can still get noticeable cognitive benefits from spending just 15 to 20 minutes in nature.

In one study, Berman and his team asked people to go for walks at different times of the year: in June, when it was nice in Michigan, and in January, when it was 25 degrees and the trees were bare. As you might have guessed, the summer group was in bliss, but the winter group did not enjoy the walk.

“But they still showed the same cognitive benefits as the people who walked in June,” he said of the latter group. “For these cognitive benefits, it's not about us liking the interaction. It's something deeper. It's how we process natural stimulation.”

The Times spoke with Berman about what he and others have discovered by studying how our natural environment affects the human psyche and how we could create more natural elements in our cities to improve our overall well-being.

This interview has been condensed and edited for clarity.

What is environmental neuroscience? Where did this term come from?

It's based on some earlier studies where people studied rodents and found that when the rodents lived in a rich environment where there were toys and there were other rodents around, those rats had more synapses in the brain, more glial cells. The physical environment in which these rodents were found [living] it affected their brain. And it really grabbed me.

[Then] I took this course from Professor Steve Kaplan and he talked about this theory called attention restoration theory and how people can regain their attention by interacting with their environment. Steve, the consultant, and I designed studies to test attention restoration theory, and I saw that there wasn't necessarily room for that kind of research in the field.

All of these rodent studies were done many years ago, and nothing connected them together. I saw all these different connections and thought that maybe I could help define this new field of environmental neuroscience, where we can actually see how the physical environment that surrounds us actually influences brain functioning, and try to combine the best techniques of cognitive neuroscience with ideas from ecological psychology.

Can you talk about the terms you use in the book: “involuntary attention” and “gentle entrainment”? It sounds like you're saying that when we're in nature, it has a way of recharging us because of the way we allocate our brain space or energy.

[Let’s] start with attention restoration theory. One of the key principles articulated by Steve Kaplan and his wife Rachel Kaplan is that people have two types of attention. One type of attention is called directed attention. This is sometimes called endogenous or top-down attention. This is the kind of attention in which you, as an individual, decide what to pay attention to. So, presumably, you decide to pay attention to me and what I say, even though it may not be the most interesting thing you can find in the environment.

I'm really interested in what you're saying, just to be clear.

[Laughs] Humans are really good at directing their attention, but we can only direct our attention so far until we become mentally fatigued and find it difficult to concentrate. We've all had that feeling at the end of a long day at work when you just stare at the computer screen and, you know, nothing happens.

When you can no longer concentrate, we say you are in a state of directed attention fatigue. You have exhausted this resource of directed attention.

This is different from involuntary attention, where our attention is automatically captured by interesting stimulation from the environment. Bright lights, loud noises and similar stimulations automatically attract our attention and we don't really have any control over it.

Like the loud noise of a motorcycle.

Yes, and such attention is believed to be less susceptible to fatigue or exhaustion. So you don't often hear people say, “Oh, I can't look at that beautiful waterfall anymore. It's too interesting to look at. I'm too tired.” One of the ideas behind attention restoration theory is that if you can find an environment that makes little demands on your directed attention, but at the same time has interesting stimulation that activates involuntary attention, you can restore or replenish it. [your] directed attention.

What could be an example of this?

We say that the stimulation that activates involuntary attention should be what we call “gentle fascination.”

When you look at this waterfall, it does not capture all the resources of your attention. You can still reflect and think about other things while you are looking at the waterfall. If you are in Times Square, this is also very interesting. It grabs most of your attention, but does so in an all-consuming way.

The type of stimulation that this calming, restorative experience gives you should be gentle, not harsh.

In the book, you write quite a bit about nature's meandering design and its benefits. For the cynics among us, I wanted to ask: can we simply design more nature around us and more of it into buildings and benefit from it without actually being in nature—without walking in a park or forest? Do we only need curves?

This way we can get some advantages. Antonio Gaudi and other architects knew this in the way they designed buildings, and people really like the types of buildings that biophilic designwhere they imitate patterns from nature in design. I don't see it as a replacement for nature. It's kind of like a supplement.

We've found that in many of our studies, immersing yourself in real nature gives you the most bang for your buck because being in nature gives you all the modalities: visual, auditory, tactile, and even olfactory, olfactory. You get an experience that I think you just can't imitate in a built space.

I wouldn't want to say, “Oh, the conclusion is that if we find all of nature's ingredients, we can destroy all of nature and then just build on it.” No, we must preserve all of nature, because we cannot create anything better than nature.

You write about the benefits of connecting with nature when a person is depressed, anxious, or grieving. What is it about nature that helps an anxious or depressed mind? Are we finally putting phones away?

We did studies with people who had been diagnosed with clinical depression, and we weren't actually sure that walking in nature would benefit them as much.

We thought, “Well, if nature increases attention and cognitive performance, and if someone is depressed and ruminates on negative thoughts and feelings, perhaps walking alone in nature might actually increase depression and increase depressive rumination.”

We conducted the same walking study [with] preclinical sample. But for clinically depressed participants, we actually encouraged them to ruminate on negative thoughts and feelings before they went for a walk. And we found that walking in nature was more beneficial for participants with clinical depression than for our preclinical samples.

We think this is because when you're depressed and ruminating on negative thoughts and feelings, it actually takes up a lot of your attention and focused attention. So nature supports them, and we think that gives them the cognitive resources to then deal with depression and rumination.

In the book you talk about how nature can make us see each other as people again. How do we, and especially parents who are concerned about their children growing up in such an inhumane culture in which we live, take advantage of this?

Some researchers from China did a study where they found that being in nature makes you less self-centered. You feel like you're part of something bigger. And then it actually enhances the sense of humanizing others. Even though there may not be people around, you start to feel more connected to everyone, in part perhaps because you feel more connected to nature.

And they found that this could even happen with houseplants, which they found enhanced feelings of humanizing others and self-transcendence. And it wasn't just nature making people feel good. It was about how nature enhances this sense of self-transcendence and then enhances the sense of humanization.

You and I have both spoken “in nature” on numerous occasions. How do you understand “in nature”? What is the starting point when our brain says, “I’m in nature”?

It's difficult to determine. It probably varies from person to person, just like your father's definition of nature. [in Oklahoma] may be different from someone living in New York or Los Angeles.

What does one person consider natural and another does not? What does seem to be very consistent across cultures is the preference for nature: people prefer things that look more natural to things that look more built.

In terms of the benefits of being in nature, how important is it for nature to be awe-inspiring? A walk in nature in the park, which an ordinary person might find boring, will it bring him any benefit?

You don't have to go to the most spectacular and beautiful nature to reap these cognitive benefits. But if nature is so boring, I don't think you'll get as much benefit as walking through a cornfield on its own. And we actually asked people, “Do you prefer being in a cornfield or walking down a tree-lined city street?” And people prefer tree-lined city streets to cornfields. You could argue that perhaps a cornfield is actually less natural than a tree-lined street because it has been heavily influenced by humans. But this simply means that not all nature is created equal, and not all cities are created equal.