The Biophilia Effect- 1

 

CONTENTS

PART ONE

LOOKING FOR NATURE NEURONS

1.     The Biophilia Effect

2.     How Many Neuroscientists Does It Take to Find a Stinking Milkvetch?

PART TWO

NEARBY NATURE: THE FIRST FIVE MINUTES

3.     The Smell of Survival

4.     Birdbrain

5.     Box of Rain

PART THREE

FIVE HOURS A MONTH

6.     You May Squat Down and Feel a Plant

7.     Garden of Hedon

8.     Rambling On

PART FOUR

BACKCOUNTRY BRAIN

9.     Get Over Yourself: Wilderness, Creativity and the Power of Awe

10.   Water on the Brain

11.   Please Pass the Hacksaw

PART FIVE

THE CITY IN A GARDEN

12.   Nature for the Rest of Us

PART ONE

LOOKING FOR NATURE NEURONS

1

The Biophilia Effect

In short, the brain evolved in a biocentric world.

—EDWARD O. WILSON

There is nothing you can see that is not a flower; there is nothing you can think that is not the moon.

—BASHO

When I pictured shinrin yoku, “forest bathing,” I conjured Sleeping Beauty in her corpse phase, surrounded by primordial trees, twittering birds and shafts of sunlight. You just knew she was somehow taking it all in, and she’d awake refreshed, enlightened and ready for her hot prince. But this was wrong on so many levels. First off, Japan doesn’t have a lot of primeval forest left, and second, you have to work at this, although corpselike moments are not discouraged. In Chichibu-Tama-Kai National Park, a ninety-minute train ride from Tokyo, I was supposed to be concentrating on the cicadas and the sound of a flowing creek when a loud Mitsubishi van rumbled by. It was disgorging more campers to a nearby tent village where kids were running around with their fishing poles and pink bed pillows. This was nature, Japan-style.

The dozen others with me on our shinrin yokuhike didn’t seem to mind the distractions. The Japanese go crazy for this practice, which is standard preventive medicine here. It involves cultivating your senses to open them to the woods. It’s not about wilderness; it’s about the nature/civilization hybrid the Japanese have cultivated for thousands of years. You can stroll a little, write a haiku, crack open a spicebush twig and inhale its woodsy, sassy scent. The whole notion is predicated on an ancient bond that can be unearthed with a few sensory tricks.

“People come out from the city and literally shower in the greenery,” our guide, Kunio, explained to me. “This way, they are able to become relaxed.” To help us along, Kunio—a volunteer ranger—had us standing still on a hillside, facing the creek, with our arms at our sides. I glanced around. We looked like earthlings transfixed by the light of the mother ship. Weathered and jolly, Kunio told us to breathe in for a count of seven seconds, hold for five, release. “Concentrate on your belly,” he said.

We needed this. Most of us were urban desk jockeys. We looked like weak, shelled soybeans, tired and pale. Standing next to me was Ito Tatsuya, a forty-one-year-old Tokyo businessman. Like many day-hikers in this country, he carried an inordinate amount of gear, much of it dangling from his belt: a cell phone, a camera, a water bottle and a set of keys. The Japanese would make great boy scouts, which is probably why they make such great office workers, working longer hours than anyone else in the developed world. It’s gotten to the point where they’ve coined a term, karoshi—death from overwork. The phenomenon was identified during the 1980s bubble economy when workers in their prime started dropping dead, and the concept reverberated into the future and throughout the developed world: civilization can kill us. Ito and I breathed in the pines and then dove into our bento boxes full of octopus and pickled root vegetables. Kunio was moving around, showing people the astonishingly twiggy walking-stick insect. Ito’s shoulders seemed to be unclenching by the minute.

“When I’m out here, I don’t think about things,” he said, deftly scooping up shards of radish while I splattered mine onto the leaf litter.

“What’s the Japanese word for ‘stress’?” I asked.

“‘Stress,’” he said.

WITH THE LARGEST concentration of giant trees in Japan, this park is an ideal place to put into practice the newest principles of Japanese wellness science. In a grove of rod-straight sugi pine, Kunio pulled a thermos from his massive daypack and served us some mountain-grown, wasabi-root-and bark-flavored tea. The idea with shinrin yoku, a term coined by the government in 1982 but based on ancient Shinto and Buddhist practices, is to let nature into your body through all five senses, so this was the taste part. I stretched out across the top of a cool, mossy boulder. A duck quacked. This may not have been the remote and craggy wilderness preferred by John Muir, but it didn’t need to be. I was feeling pretty mellow, and scientific tests would soon validate this: at the end of the hike, my blood pressure had dropped a couple of points since the start of the hike. Ito’s had dropped even more.

We knew this because we were on one of Japan’s forty-eight official “Forest Therapy” trails designated for shinrin yoku by Japan’s Forestry Agency. In an effort to benefit the Japanese and find nonextractive ways to use forests, which cover 68 percent of the country’s landmass, the agency has funded about $4 million in forest-bathing research since 2003. It intends to designate one hundred Forest Therapy sites within ten years. Visitors here are routinely hauled off to a cabin to stick their arms in blood pressure machines, part of an effort to provide ever more data for the project. In addition to its government-funded studies and dozens of special trails, a small number of physicians in Japan have been certified in forest medicine. It’s hard to overstate how unusual this is.

“The Japanese work is essential in my mind, a Rosetta stone,” Alan Logan, a Harvard lecturer, naturopath and member of the scientific committee of the International Society of Nature and Forest Medicine (which is, naturally, based in Japan), had told me. “We have to validate the ideas scientifically through stress physiology or we’re still at Walden Pond.”

The Japanese have good reason to study how to unwind: In addition to those long workdays, pressure and competition for schools and jobs help drive the third-highest suicide rate in the world (after South Korea and Hungary). One-fifth of Japan’s residents live in greater Tokyo, and 8.7 million people have to ride the metro every day. Rush hour is so crowded that white-gloved workers help shove people onto the trains, leading to another unique term, tsukin jigoku— commuting hell.

THE CIRCUMSCRIBED, urban life is of course not unique to Japan. I now reflected the nature-deprived trends myself. I spend too much time sitting inside. I maintain multiple social-media platforms that attenuate my ability to focus, think and self-reflect. Since moving to D.C., I’ve had crying jags in traffic jams, and at times I’ve been so tired I’ve had to pull over and nap on MacArthur Boulevard. When I do get out “in the woods,” I seem to be doing it all wrong, forgetting or unable to hear the birds or notice any dappled anything. Instead, I grumble and obsess over my fate, my relationships and my kids’ new schedules, which require military precision and Euclidean traffic calculations.

A couple of months after I moved, I told my new doctor I was feeling depressed. She did what general practitioners everywhere are doing and sent me off with a script for Zoloft. One in four middle-aged American women takes or has taken an antidepressant. One in fourteen children takes a drug for emotional or behavioral problems, reflecting about a fivefold increase since 1994. For me, as for a sizable percentage of others with mild depression, the meds didn’t seem to work, and I hated the common side effects, which include everything from headaches to insomnia to low libido.

Moving on, I tried to grasp the destress crowd’s favorite darling, meditation. The science is very convincing that it changes your brain in ways that make you smarter and kinder and generally less ruffled by life. The problem is, as with antidepressants, meditation doesn’t work for many of us. Only 30 percent of aspirants are “fully adherent” after a standard eight-week course, according to Joshua Smyth, a biobehavioral psychologist at Pennsylvania State University. It has a high threshold to enlightenment.

But pretty much any slouching screen fiend can spend time in a pocket of trees somewhere. If there was one man who can demonstrate how forest therapy works, it’s Yoshifumi Miyazaki. A physical anthropologist and vice director of the Center for Environment, Health and Field Sciences at Chiba University on the outskirts of Tokyo, he believes that because humans evolved in nature, it’s where we feel most comfortable, even if we don’t always know it.

In this, he is a proponent of a theory popularized by the widely revered Harvard entomologist E. O. Wilson: the biophilia hypothesis. It’s been more or less appropriated by environmental psychologists into what’s sometimes called the Stress-Reduction Theory or Psycho-Evolutionary Restoration Theory. Wilson didn’t actually coin the word “biophilia”; that honor goes to social psychologist Erich Fromm, who described it in 1973 as “the passionate love of life and of all that is alive; it is the wish to further growth, whether in a person, a plant, an idea or a social group.”

Wilson distills the idea more precisely as residing in the natural world, identifying “the innately emotional affiliation of human beings to other living organisms,” as an evolutionary adaptation aiding not only survival but broader human fulfillment. Although no specific genes have been found for biophilia, it’s well recognized—ironically, some from studies of biophobia or fear—that even today our brains respond powerfully and innately to natural stimuli. One powerful example: snake! Our visual cortex picks up snake patterns and movements more quickly than other kinds of patterns. It’s likely that snakes even drove the evolution of our highly sensitive depth perception, according to University of California anthropologist Lynne Isbell. She discovered special neurons in the brain’s pulvinar region, a visual system unique to humans, apes and monkeys. Primates who evolved in places seething with venomous snakes have better vision than primates who didn’t evolve in those places.

But survival wasn’t only about avoiding harm. It was also about finding the best food, shelter and other resources. It makes sense that certain habitats would trigger a neural bath of happy hormones, and that our brains would acquire the easy ability to “learn” this in the same way we learn to fear snakes and spiders. Going beyond that, our ancestors also had to learn how to recover from stress, Pleistocene-style. After they were chased by a lion or dropped a precious tuber over a cliff, they had to get over it in order to be welcomed back to the tribe, without which there was little survival. The biophilia hypothesis posits that peaceful or nurturing elements of nature helped us regain equanimity, cognitive clarity, empathy and hope. When love, laughter and music weren’t around, there was always a sunset. The humans who were most attuned to the cues of nature were the ones who survived to pass on those traits. Biophilia explains why even today we build houses on the lake, why every child wants a teddy bear, and why Apple names itself after a fruit and its software after noble predators, surfing spots and national parks. The company is brilliant at instilling biophilic longing and affiliation at the very same time it lures us inside.

It should come as no surprise that crosstalk operates between the brain and nature, but we’re less aware of the ever-widening gulf between the world our nervous systems evolved in and the world they live in now. We celebrate our brains’ plasticity, but plasticity goes only so far. As Miyazaki explained it, “throughout our evolution, we’ve spent 99.9 percent of our time in nature. Our physiology is still adapted to it. During everyday life, a feeling of comfort can be achieved if our rhythms are synchronized with those of the environment.” Of course, he’s talking about the nice parts of nature found in the hillsides of Japan, not the pestilential scum ponds or barren terrains of the globe that also constitute nature. Stick an office worker there, and relaxation will likely not be happening. But Miyazaki points out that naturalistic outdoor environments in general remain some of the only places where we engage all five senses, and thus, by definition, are fully, physically alive. It is where our savanna-bred brains are, to borrow from John Muir, “home,” whether we consciously know it or not. By contrast, Muir wrote of time not in the wilderness: “I am degenerating into a machine for making money.” Make that a machine with clogging pipes.

To prove that our physiology responds to different habitats, Miyazaki’s taken hundreds of research subjects into the woods since 2004. He and his colleague Juyoung Lee, then also of Chiba University, found that leisurely forest walks, compared to urban walks, deliver a 12 percent decrease in cortisol levels. But that wasn’t all; they recorded a 7 percent decrease in sympathetic nerve activity, a 1.4 percent decrease in blood pressure, and a 6 percent decrease in heart rate. On psychology questionnaires, they also report better moods and lowered anxiety.

As Miyazaki concluded in a 2011 paper, “this shows that stressful states can be relieved by shinrin therapy.” And the Japanese eat it up, with nearly a quarter of the population partaking in some shinrin action. Hundreds of thousands of visitors walk the Forest Therapy trails each year.

I MET UP WITH Miyazaki at the country’s newest proposed therapy site, Juniko state park on the edge of the Shirakami Mountains in northern Japan. He was swatting mosquitoes from his face and neatly trimmed gray hair. He wasn’t looking relaxed at all. It had rained recently, and he was worried the trail might be too muddy for his upcoming walking experiment. He was kicking some rocks out of the way and overseeing the setting-up of a netted, canopied minilab. The next morning, Miyazaki and Lee would be bringing twelve male college-student volunteers here, measuring various vital signs after they walked and sat and generally forest-bathed. Then they would repeat the experiment the next day in downtown Hirosaki, a city of 100,000, two hours away by car. I would join as one of Miyazaki’s guinea pigs.

The trail deemed walkable, several of us retired to a quiet restaurant in Hirosaki. We took off our shoes and sat cross-legged on the floor while Miyazaki ordered and then distributed a baffling array of dishes involving goopy eggs, gelatinous balls and surf-and-turf combinations.

“Why do the Japanese think about nature so much?” I asked Miyazaki, who was preparing to eat a manta ray.

“Don’t Americans think about nature?” he asked me.

I considered. “Some do and some don’t.” But I was thinking, an amazing amount of us don’t, given our downward trends in outdoor time and visits to parks.

“Well,” he mused. “In our culture, nature is part of our minds and bodies and philosophy. In our tradition, all things are relative to something else. In Western thought, all things are absolute.”

Maybe it was the sake, but he was losing me.

“The difference is in language,” he continued. “If I ask you, ‘Is a human a dog?’ you say, ‘No, a human is not a dog.’ In Japan, we say, ‘Yes, a human is not a dog.’ The great sensei of nature research peered at me over his chopsticks. I was reminded of the story of the Zen student who asks his teacher, “How do you see so much?” and the teacher responds, “I close my eyes.”

Miyazaki’s answer, I understood, was like a koan, tantalizing and confounding at the same time. But you had to trust the guy was onto something.

THE NEXT MORNING, the college boys and I took turns sitting in the mobile lab at the trailhead. We placed hard cotton cylinders under our tongues for two minutes, then spit them out into test tubes. That would record our levels of cortisol, a hormone made in the adrenal cortex. We got hooked up to probes and devices. The team was inaugurating a brain-measuring, battery-powered, near-infrared spectrometer that, when deployed, gave me a sensation of leeches sticking to my forehead. We’d repeat all these measurements at the end of the walk and again in the cityscape.

To gauge our physiological responses to these environments, Miyazaki and Lee look at changes in blood pressure, pulse rate, variable heart rate, salivary cortisol and, new this year, hemoglobin in the brain’s prefrontal cortex. When aggregated, these metrics paint a picture of our bifurcated nervous system. When we are relaxed and at ease in our environment, our parasympathetic system—sometimes called the “rest and digest” branch—kicks in. This is why food tastes better in the outdoors, explains Miyazaki. But the demands and constant stimuli of modern life tend to trigger our sympathetic nervous system, which governs fight-or-flight behaviors. And trigger it, and trigger it. We suffer the consequences: a long trail of research dating back to the 1930s shows people who produce chronically high cortisol levels and high blood pressure are more prone to heart disease, metabolic disease, dementia and depression. More recent research shows that the steady stress of urban living changes the brain in ways that can increase our odds of schizophrenia, anxiety and mood disorders.

When it was my turn to wander through the forest for fifteen minutes, I was happy to break free from the wires. The loud pulse of cicadas echoed through the woods. Light filtered gently through the beeches and Japanese horse chestnuts and the earth smelled like good damp dirt. An elderly couple ambled by, assisted by walking sticks and a bear bell. I was briefly mesmerized by a yellow butterfly. I could see why Juniko, a leafy network of trails and lakes, is a candidate for the country’s next forest therapy station. Local and park officials are seeking the designation because where there’s forest therapy, there are tourists and their yen. Miyazaki may have a mystical side, but what drives him is more data. It’s a convenient arrangement.

The Japanese work on physiology and the brain takes advantage of new tools of brain science, but it builds on decades of psych-talk about the health benefits of being in nature. Miyazaki wasn’t the first to record physical stress recovery in nature. A young psychologist named Roger Ulrich was curious why so many Michigan drivers chose to go out of their way to take a tree-lined roadway to the mall. In 1986, using the expensive and cumbersome equipment of the time, he hooked up an electroencephalograph (EEG) unit to the heads of healthy volunteers while they viewed slides of nature scenes or utilitarian urban buildings. The subjects assigned to nature showed higher alpha wave activity, a wavelength associated with relaxation, meditation and increased serotonin. In another experiment, he stressed out 120 students by showing them movies of bloody accidents in a woodworking shop. He knew they were distressed because he measured their sympathetic nervous activity—the sweat glands on their skin, their heart rates and their blood pressure. Afterward, some students were assigned to watch a ten-minute video of nature scenes and some to watch videos of urban scenes, from a pedestrian mall to cars on a road. The results were dramatic: within five minutes, the brains-on-nature returned to baseline. The brains-on-built-environment recovered only partway—as indicated by those nervous system measures— even more than ten minutes later.

Despite early promise, the study of brains-on-nature went fairly dark for a couple of decades. It was considered soft science, much of it based on qualitative measures in a medical world dazzled by genetics and modern chemistry and funded by pharmaceutical companies that didn’t stand to make a profit from houseplants or garden views. The renewed interest of late represents a convergence of ideas and events: the relentless march of obesity, depression and anxiety (even in affluent communities and despite more medication), the growing recognition of the role of the environment on genes, and the growing academic and cultural unease with our widening breach from the outdoors.

NOT SURPRISINGLY, MY urban peregrination wasn’t quite as pleasant as the soft green trail of Juniko. Downtown Hirosaki is far less green than D.C. There are transit stations, shops selling basic goods, and people on the go. In the height of summer, the asphalt was baking. Shoppers rushed in and out of a department store whose busy windows advertised “spaghetti with tomato cream.” I passed four parking lots, two taxi stands, a bus station, and two loudly idling buses belching fumes. My nervous system responded. My systolic blood pressure had dropped six points after walking in the forest. It went up six points after walking in the city. Which of course begs the question: How long do the feel-good effects of nature last? Do they just get wiped out by the first traffic jam or cell phone tone?

Miyazaki’s sometime collaborator, an immunologist in the department of environmental medicine at Nippon Medical School in Tokyo, wondered the same thing. Qing Li is interested in nature’s effect on mood states and stress as manifested in the human immune system. Specifically, he studies natural killer immune cells, called NK cells, which protect us from disease agents and can, like cortisol and hemoglobin, be reliably measured in a laboratory. A type of white blood cell, they’re handy to have around, since they send self-destruct messages to tumors and virus-infected cells. It’s been known for a long time that factors like stress, aging, and pesticides can reduce your NK count, at least temporarily. So, Li wondered, if nature reduces stress, could it also increase your NK cells and thereby help you fight infections and cancer?

To find out, Li brought a group of middle-aged Tokyo businessmen into the woods in 2008. For three days, they spent a couple of hours each morning hiking. By the end, blood tests showed their natural killer cells had increased 40 percent. Moreover, the boost lasted for seven days. A month later, their NK count was still 15 percent higher than when they started. In contrast, during urban walking trips of the same duration, NK levels didn’t change. Since then, Li has published results from similar studies with male and female subjects in half a dozen peer-reviewed journals. In one, Li was curious to know if a one-hour trip to a city park would have a similar effect, since most of us can’t spend three days a week walking in the woods. It did, although the immune surge didn’t last quite as long.

What was going on? Li suspected the trees. Specifically, he wondered if NK cells are boosted by “aromatic volatile substances,” otherwise known as nice tree smells, and sometimes called phytoncides. These are the turpenes, pinenes, limonenes and other essential oils emitted by evergreens and many other trees. Scientists have identified over a hundred of these phytoncides in the Japanese countryside, and virtually none in city air that’s not directly above a park. This wasn’t a totally left-field idea. Since at least 2002, studies have attributed healthful properties to soil compounds like actinomycetes—which the human nose can detect at concentrations of 10 parts per trillion—and of course we harvest mold spores to make critical antibiotics like penicillin. Dirt can heal: in two separate experiments in England and the United States in 2007 and 2010, the mice lucky enough to be exposed to a common soil bacterium, Mycobacterium vaccae, performed better in a maze, showed less anxiety and produced more serotonin, a neurotransmitter many scientists think is associated with happiness.

To test the phytoncide theory, Li locked thirteen subjects in hotel rooms for three nights. In some rooms, he rigged a humidifier to vaporize stem oil from hinoki cypress trees, which are common in Japan; other rooms emitted eau-de-nothing. The results? The cypress sleepers experienced a 20 percent increase in NK cells during their stay, and they also reported feeling less fatigued. The control group saw no changes.

“It’s like a miracle drug,” said Li, when I interviewed him at his university lab in Tokyo.

It sounds totally hokey, even unbelievable, that evergreen scents—not unlike the thing that dangles from taxicab rear-view mirrors—could help us live longer. But Li found similar results with NK cells exposed to phytoncides in a petri dish. The cells increased, and so did anticancer proteins and proteases called granulysin, granzymes A and B and perforin, which cause tumor cells to self-destruct. It’s unclear whether there’s something magical in the aromatic molecules or if the smell simply makes people feel good, reducing stress. Li’s olfaction theory is unconventional, but it contains some of that zen five-sense wisdom. While American researchers are mostly showing people pictures of nature or sending them out for loops around the campus green, the ones in Japan are practically pouring it into every orifice.

Li, the chairman of the Japanese Society of Forest Medicine, uses some of his insights in his own life. “In fact,” he said, “I use a humidifier with cypress oil almost every night in the winter!” You don’t need to harvest your own; he said standard health-store aromatherapy oils should do the job.

“What else do you recommend?” I asked the middle-aged man with the bowl haircut.

Clearly, Li gets asked this a lot. He had a small list. “If you have time for vacation, don’t go to a city. Go to a natural area. Try to go one weekend a month. Visit a park at least once a week. Gardening is good. On urban walks, try to walk under trees, not across fields. Go to a quiet place. Near water is also good.”

I could see my morning walk back in D.C. transforming before my eyes.

I COULDN’T HELP wondering, though, if having more data on how nature changes our brains and immune cells would actually lure more of us into the woods. We also know we’re supposed to eat more leafy greens, but most of us don’t. The kale analogy is pretty apt, because it turns out that even when we don’t like nature, such as during lousy winter conditions, it ends up benefiting us. At least that’s what University of Chicago professor Mark Berman found when research subjects took walks in an arboretum during a blustery winter day. The walkers didn’t enjoy themselves, but they still performed better on tests measuring short-term memory and attention. We’ll learn more about his work in the next chapter.

While the Japanese researchers understand our draw to nature, many American ones seem preoccupied with our pull away from it, our distractions, inertia and addictions. They want to know if resisting that pull and turning toward nature can enhance our productivity. Perhaps this cultural difference is what Miyazaki was explaining over his plate of sting ray: oneness versus me-ness. Americans want to know what can nature—that stuff over there— do for us? More Beowulf than Basho, the Americans want to slay the dragon and get back to the mead hall. They prefer to use delineated spurts of nature to optimize their success. Maybe they can even use digital nature and forget the bugs and rain altogether.

I would head back to the States, to Utah, to see what some American researchers were up to and how they were preparing to tackle the research. Their inquiries, geared to cognition and creativity, provide the other main theoretical framework for understanding how nature acts on our brains. In the meantime, I would be scratching and sniffing some pinecones. The bark tea? Not so much. Running my hands through the moss, sure.

Why not? After all, yes, I am not a dog.

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