The Biophilia Effect
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 ChichibuTama-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 yoku hike 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 dayhikers
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 th
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 mountaingrown,
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 forestbathing
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 bee
doing and sent me off with a script for Zoloft. One in four middleaged
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 PsychoEvolutionary
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, Pleistocenestyle.
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 savannabred
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
- 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 collegestudent
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 brainson-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.