Go Wild

by John J. Ratey

  The logic of this is as follows: Humans, and all species, for that matter, succeed as a species only to the degree they are able to adapt to their environments. Humans, though, did this in part with big brains, by exercising a knowledge of the natural world—a task made more complex for our species by our varied habits and habitats and variety of diet, as we have already explored. Imagine for a moment how simple attentiveness to one’s surroundings becomes when amplified with a bit of obsessiveness, of fascination, of real attachment—not merely observing but reveling in the conditions of nature. People with this trait would be more likely to survive. This is not to argue that there is a gene or a hormone for biophilia. Like most interesting traits in humans, this is far more likely a number of traits working together in a networked system. But it’s easy enough to see how evolution might reward and amplify those traits. For example, an attraction to the color red causes one to notice it more, and in nature, red often equals ripe fruit.

  And so it follows, as was the case with motion and running, protein and fats and sleep, that elements of our sense of well-being and happiness are wrapped up in this trait. This is a hypothesis we can take to the lab (and we will), but our first preferred venue for testing this idea is an ordinary scene. Most of us who have wandered forest trails, or even strolled urban parks, or even driven a scenic highway, can conjure this thought experiment. Think of the place in such a hike or drive where you stop to take it all in. On the highway, there will be a sign marking the “scenic turnout,” a sign erected not because some highway engineer thought this was an opportune place to pull over but because so many people actually did pull over and the engineers needed to accommodate the demand. This tells us something in and of itself—but the parallel scene on a mountain trail tells us more. It often comes miles up the trail after winding through rock, scree, and trees, to a ridgetop and a grassy park with a sweeping view of a valley below, when a broad expanse of territory reveals itself—and then comes your urge to stop and take it in, to rest and settle with the peace of the place.

  We brought you to this ordinary scene in the mountains for a reason. Look around for a moment—not to the panorama, but at your feet, on the ground. If you are in a place where mule deer or elk live, you will notice that this particular spot is littered with droppings. And just this spot. Everything you crossed en route was not so littered, despite the fact that the rest of your hike was an elk and deer habitat as well. This means simply that the elk bed here, spending sunny afternoons lounging and taking in the day. Those elk feces are hard evidence of our thesis, a deep kinship between you and those strange majestic animals, the sense that both of you have an innate preference for places like this because the vista makes you safe from predators and gives you vital knowledge of your surroundings. You can see, and you are safe. Evolution has written this in your programming for the same reasons it has written the same instructions in the program of elk. And for a moment in this place, animals do not know way more than you do. You read the signs the same as a wild elk does, and the signs say you are home.

  This simple idea can translate into hard dollars and cents. Rooms with a view or houses fronted by a lake or stream replicate conditions important to us throughout evolution. Anthropologists who have studied bushmen invariably note that the nomadic wanderings of hunting and gathering are governed by daily cycles that place people in safe camps at night, always with access to water and with an unobstructed view of the surroundings. There is no reason for that preference to hold up millennia later other than a genetic memory—but an apartment with a commanding view of Central Park or waterfront property costs more. This is a measure of biophilia, the price tag on our genetically programmed preference for certain places.

  The idea of biophilia has undergone rigorous testing, specifically the idea that we humans, just like any creature with a long history of serving as meat for predators, still seem to prefer vistas and fear enclosed spaces. There is, however, a flip side to this phenomenon that turns out to be just as telling: along with biophilia, there is a balancing set of predispositions tuned to our ancestral enemies. Besides preferences, we ought to have fears that are genetically encoded, biophobias, confirmed in a number of cross-cultural, controlled studies that show an innate aversion to creatures like spiders and snakes (especially snakes). These details are even more illuminating.

  Some experiments do indeed show an innate fear of snakes, but in others researchers instead found what psychologists call “biologically prepared learning.” That is, we seem to have pre-wired circuitry for learning some things better than others. We learn to fear spiders and snakes very quickly and retain the learning better than we retain other sorts of conditioning; this difference is most telling when compared with our learning about real hazards in the modern world.

  Most of us today have far more reason to fear bare electrical wires or traffic than snakes, and yet researchers have found no innate aversion to or prepared learning about these, nor abilities to retain conditioned responses or learned experiences. This is in sharp contrast to the same sorts of experiences with spiders and snakes and fear of heights. Our modern world is full of hazards and pitfalls, and almost none of them are natural or anything like what our ancestors feared—and yet our minds dwell on the same fears that our ancestors had. A highway fatality now barely makes a headline, but a lethal grizzly bear attack gets page one play and is all the buzz on Twitter and Facebook the following day. All of which steers us toward an interesting conclusion.

  “It suggests that when human beings remove themselves from the natural environment, the biophilic learning rules are not replaced by modern versions equally well adapted to artifacts,” writes Wilson. “The brain evolved in a biocentric world, not a machine-regulated world. It would be therefore quite extraordinary to find that all learning rules related to that world have been erased in a few thousand years, even in the tiny minority of peoples who have existed for more than one or two generations in wholly urban environments.”

  Yet as a practical matter this offers enormous opportunity. Our attention to this topic is drawn not so much by vestigial fears of spiders and snakes; we are pursuing this idea because it points to some easily reachable antidotes and pathways, even literal pathways, and to our well-being in everyday life, urban and otherwise.

  It’s easy to see how society might have missed the importance of maintaining our ties to natural surroundings, and in fact there is research on this very issue. One study in particular demonstrates not only that contact with nature, something as simple as a walk in the park, makes us measurably better and a bit smarter but that the participants in the study underestimated the benefits. That is, the subjects tested better on some mental performance measures than they thought they would and didn’t credit their walk in the park for the improvement.

  The research was the work of the Canadian psychologists Elizabeth K. Nisbet and John M. Zelenski, who wrote: “Modern lifestyles disconnect people from nature, and this may have adverse consequences for the well-being of both humans and the environment.”

  Their work fits within a larger body of research from around the world, and the net result of all of this is that we probably can remove the qualifier “may” from the above statement.

  When we deny these preferences, these innate attachments to nature, we suffer, and this is a big part of what ails us in a high-tech world of artifice that’s increasingly disconnected from nature. The author Richard Louv has argued that this is a key affliction of civilization, even going so far as to give it a name: nature deficit disorder. Louv built his case on ten years’ worth of interviews with parents in the United States and concluded that the glitzy attractions of the virtual world, coupled with what he cites as oversensationalized media coverage about the dangers of the outdoors, have created an epidemic of detachment from nature among modern children and, by extension, adults.

  This is troubling enough, even on the obvious level that nature contains all of biological life, and children ought to gain
the knowledge and appreciation on offer in the wild. But Louv and others point out that there are more subtle issues, and those parallel some we have already talked about in detailing the afflictions of civilization. To cite a few, play in nature exposes kids (and everyone else) to a full range of microbes to support their internal microbiomes and challenge and tune their immune systems; these microbes also fight autoimmune disease, the epidemic of absence. Also, play outdoors exposes people to the full spectrum of light, with a variety of benefits, not the least among them regulating melatonin and sleep cycles but also making for healthy levels of vitamin D. Shortage of vitamin D is an epidemic in its own right, but in this light, it is also a subset of the epidemic of nature deficit disorder.

  All of this goes a long way to explain why we are evolved to be in nature, and therefore to value it. All of this supports the hypothesis of biophilia.

  Much of this line of thought began in the late 1970s in Ann Arbor, an appropriate center of origin given that its very name includes a reference to trees. While working on his PhD in geography, Roger S. Ulrich happened to notice that Ann Arborites on their way to a mall had a habit of driving out of their way to avoid a freeway and instead took a tree-lined route. That began a series of research projects to demonstrate that these people were in fact deriving some benefit from the eccentric (and more costly) route. Ulrich used an EEG to measure alpha wave activity in research subjects. Alpha waves are associated with serotonin production, and serotonin counters depression. Natural scenes and association with nature did indeed show positive results with alpha waves, and both also had a positive effect against anxiety, anger, and aggression.

  In their 2012 book, Your Brain on Nature: The Science of Nature’s Influence on Your Health, Happiness, and Vitality, the authors Eva M. Selhub, a medical doctor, and Alan C. Logan, a naturopath, summarize Ulrich’s work along with examples from around the world. Among them: subjects in an adult care center in Texas showed decreased cortisol levels (the stress hormone) when in a garden setting; a study in Kansas using EEG showed less stress in subjects when plants were in the room; researchers in Taiwan, using measures like EEGs and skin conductance, noted therapeutic effects in subjects viewing streams, valleys, rivers, terraces, water, orchards, and farms; 119 research subjects in Japan showed less stress response when transplanting plants in pots than they did when simply filling pots with soil; and another group of subjects in Japan had lower heart rates after viewing natural scenes for twenty minutes.

  Japan, in fact, is the center of some of the most interesting and innovative thinking about this issue; the research has been formalized through the Japanese Society of Forest Medicine and a national movement called shinrin-yoku, which translates poorly into English but means something like bathing or basking in the forest. The movement has spawned a series of studies that use objective markers like cortisol, heart rate, and blood pressure to demonstrate that there are real and measurable benefits to well-being and mental performance through simple contact with nature. For instance, a number of studies have shown that people in hospitals get better measurably faster if they are in a room with a window or have a bit of green as simple as a potted plant. Placing potted plants in view of workers at one factory reduced time lost to sick leave by 40 percent.

  One of the more interesting findings in the Japanese research is a sort of Goldilocks effect that shows up with trees and potted plants, and results have been replicated elsewhere. It seems there is a sweet spot. Up until that point, benefits to one’s well-being increase when more plants or trees are introduced to a room—but beyond the sweet spot, subjects begin to feel worse. Too many plants or trees, and we begin to feel uneasy. The herd of elk we visited earlier could predict this response. It replicates our ease with open views but relative unease in overdense forests, where we and elk were more vulnerable to predators in evolutionary times. The dense forest, as Dorothy and her friends understood, was the habitat of lions and tigers and bears—even in Oz.

  Taken together, these findings begin to offer some advice for public policy and design. That is, greenways, open space, landscaping, and even potted plants ought to be integrated into any efficient design of urban space as a simple, cost-effective investment in public health and tranquility. Research in both schools and workplaces has demonstrated clearly that performance of students and workers increases as a result of these simple, low-cost, and uncontroversial measures.

  Japan leads not only in research into the tangible benefits of exposure to nature but also in the commitment to making it happen. The government has already invested $4 million in research and over the past ten years has launched one hundred forest therapy centers around the country. The movement is taking root throughout Asia, with active research in Taiwan and Korea. The government of South Korea is spending $140 million on a forest therapy center.

  But where this becomes really interesting is in more costly matters like health care, and indeed some of the more sophisticated research has demonstrated that death rates from diseases like cancer decline in areas with more forest cover. Researchers used GIS (geographic information system) mapping tools to control for all other factors, like smoking and socioeconomic status, and found that the dominance of forests alone decreased death rates from cancer. This macro-level series of investigations gets support from individual research that demonstrates a positive immune response from natural settings. Demonstrably and measurably, simple exposure to nature makes you more resistant to disease.

  A study in the Netherlands examined the records of 195 doctors who served a total of 345,143 patients. Researchers were looking for a correlation between living near green space and the rate of morbidity, or being sick. They found rates lower for fifteen of twenty-four diseases examined for those people living within a kilometer of green space, and the relationship was especially important for poorer people. The benefits of green space were strongest for those with anxiety disorders and depression.

  Yet as Nisbet noted in individual subjects—even subjects getting the direct benefit of this exposure—people fail to appreciate the value of green space, which is likely an enormous factor in why this is also underappreciated in public policy. But the fine details of our cluelessness on this topic become even more interesting and suggest that there is far more to this than we might think. Some of the research with biophobia of spiders and snakes, for instance, used subliminal exposure to pictures of the creepy crawlers. Participants were shown video of some innocuous scenes, and researchers slipped in a picture of a snake that was not really visible—it was present for only a few milliseconds, passing too fast to be comprehended. Yet there was still a fear response. And there wasn’t a parallel response to subliminal exposure to more modern hazards like bare electrical wires. At least in this experiment, nature was having a measurable effect on subjects’ emotional states, and the subjects had no idea why.

  This lack of perception is even more interesting as seen in some work done with shinrin-yoku in Japan that looked at aromas in the forests. Trees and other plants exude literally scores of phytochemicals that make their way to our olfactory system, which provides a direct pathway to the brain. The class of chemicals involved are called phytoncides, and many of them have profound effects on the brain, such as lowering stress hormones, regulating pain, and reducing anxiety. Notably, some of them up-regulate powerful tools in our immune systems called natural killer cells, first-line defensive weapons against infections like influenza and common colds. Yet many of these phytoncides are undetectable as aromas. We have no idea that a natural setting is chemically stimulating our immune systems as we simply inhale the open air.

  Interestingly, the Japanese research showed that this increased immune response endured. A group of Japanese businessmen who were the research subjects showed a 40 percent increase in natural killer cells after a walk in the woods, but follow-up research showed that their killer cells were still elevated by 15 percent over baseline a month later.

  Yet by now, you may be noticing t
hat there’s something else in the air, that the pathways and effects of nature parallel those we talked about with sleep, exercise, nutrition, and even meditation. There’s more to this. As with these other topics, researchers have begun to use fMRIs in their research; as a result, they have found where exactly it is that nature works in our brains, even pinpointing it as specifically as the parahippocampal gyrus, which is an area rich in opioid receptors (special cells for attaching to opioids, a family of chemicals that includes drugs like morphine and has powerful effects on the brain).

  “This was an incredible finding, revealing that nature is like a little drop of morphine for the brain,” write Selhub and Logan.

  Korean researchers took this a step further and found that urban settings activated a brain area associated with anger and depression, but that natural scenes produced a pronounced effect in the anterior cingulate and insula. This is an important center for empathy, and the effect was confirmed through psychological tests in which people are asked to give away money to other people, exactly as was the case with the meditation studies we cited. And just as with meditation, there was no goal or described pathway for becoming a more empathetic person. Just as the simple act of calming one’s brain made one more empathetic, so did a simple walk in the woods.

  All of this research seems to be steering us to an almost mystical aspect of biophilia because we are dealing with the unseen and unperceived. Yet it is not mystical or supernatural—just real physical forces we have no ability to perceive (or maybe our urban ways have deprived us of the ability to perceive them). Maybe this is what so fascinates and engages hunter-gatherers or the Koyukon people we spoke of in the last chapter. Maybe they are so engaged with the natural world because the conditions of their lives have trained their minds to see and comprehend the gorilla in the room, a real presence that pulls them in and makes them happy. We mean to leave this possibility open for you to explore.