STANDING IN HER BASEMENT surrounded by books, photos, extra dishes for parties, gardening tools, and old furniture, Holly Rose knew it was time to pare down. The evidence of her well-stocked life was neatly organized, but it was too much. Rose and her husband planned to move to a smaller home — “right-sizing,” she called it. And as she looked around the basement, she remembers thinking Do I really need all this stuff?
Ali Powers and her boyfriend, Artie Yowell, asked the same question at the Watertown Target. On a recent weekend, the store was packed with shoppers pushing carts filled to the brim. Staring into theirs, Powers shook her head. “We came for scouring powder and here we are buying bedding,” she said. “You’ve got a color I like and a color he likes. We’re going to decorative pillows next — decorative pillows. Like we really need those.”
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Rose and the couple at Target aren’t alone. MJ Rosenthal, a professional organizer based in Newton, says the average American home contains 300,000 items, from sofas to salad forks. A couple of years ago, Forbes reported that the average American woman owns 30 outfits, up from nine in 1930. And consumers in the United States, a country with 3.1 percent of the world’s children, buy 40 percent of the world’s toys. It’s no wonder that storage facilities make up the fastest-growing segment of the commercial real estate industry.
But maybe the human impulse to acquire isn’t entirely our fault. After hundreds of thousands of years spent living with scarcity, we’re predisposed to accumulate. We are buying far more than we need, craving goods, services, and food in seemingly endless quantities. The evidence of our urge to buy is everywhere, from toys piled curbside on trash day to overstocked refrigerators filled with moldy food to demands for professional organizers.
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Why keep doing this? Partly because the dopamine boost we get from buying something makes us feel good. “No behavior happens without [the brain’s] complex and amazingly designed reward system weighing in,” says Dr. Ann-Christine Duhaime, a pediatric neurosurgeon investigating the connections between brain chemistry and consumption. “Our brain evolved with this wonderful system, but now it doesn’t know when to stop. Now your urges to eat get you in trouble, and your urges to get stuff are getting the planet in trouble.”
Our seemingly insatiable desire to acquire depletes our bank accounts and hurts the environment. We know the harm done from pollution and deforestation. We know our trash is floating in the ocean, more than 5 trillion plastic pieces of it. And we know we waste more than 20 pounds of food per person each month.
It turns out that telling people to adopt more environmentally friendly behaviors is about as effective as asking people to lose weight or quit smoking. Research shows that relationships and experiences bring us more pleasure than buying stuff, but we still struggle to change our consumption habits and simplify our lives. Rosenthal sees this playing out with her clients: “Even though they know they don’t necessarily need it, the act of letting go is a really difficult one.”
Duhaime believes that telling people to behave differently isn’t effective because it doesn’t take the brain’s reward system into account. “You can’t change how the reward system is designed to work,” she says. But you can work with the brain’s equipment to change behavior. The question at the heart of Duhaime’s research is: Can you reframe choices in a way that harnesses the reward system? Can you make reusing furniture as much fun as buying new furniture? (The shabby chic home decor craze may offer some insight there.) Can a travel agency get customers excited about taking trips that don’t require gas-guzzling air travel? And can it all be done on a scale large enough to make a difference?
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THIS MARCH, THE BRAIN PRIZE, a roughly $1 million research award, went to three neuroscientists studying how the reward system affects decision making. Wolfram Schultz, one of the winners, says that a “biological process” drives people to purchase bigger cars and houses and to strive for promotions. He describes dopamine neurons as “little devils in our brains” that make us seek more rewards. The chairman of the Brain Prize selection committee said that the winners’ work had implications for “social science, drug addiction, and psychiatry.”
Duhaime sees implications for the environment, too. The 61-year-old neurosurgeon studied the brain’s reward system as an undergraduate at Brown University, spending summers in a psychology lab inserting deep brain stimulators into rats to learn what drove their behavior. That work made her curious about how brain chemistry influences decision making.
Our brain’s reward system evolved for survival, encouraging behavior that led to greater consumption, which helps explain some modern-day habits. We often take in more calories than we need because long ago we didn’t know when we’d get our next meal. We get a little rush when we find a parking space close to our destination because an unpredictable food supply encouraged us to save our energy. We get a shopper’s high when buying a new toy or a new television or a new car, because during times of scarcity, any material good was prized.
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When we do something that our brain values, we receive small hits of dopamine, and, Duhaime says, “the brain uses this input to influence what you do next.”
The upshot: The reward system makes us want to repeat certain behaviors — even when they’re long past the point of being beneficial. In affluent countries, we live in a world of more accessible, more predictable rewards. And the easier it is to get what you want when you want it, the less satisfying it becomes. You need to consume more and more to get the same high. Anyone familiar with addiction to drugs, gambling, food, or shopping understands that dangerous cycle.
And there’s more to wanting more. Leaning forward in her office chair, as if revealing a secret, Duhaime says your reward system’s “main job is not to make you feel good. Its main job is to help judge and integrate and reinforce what you need to learn to survive.” So, in addition to taking care of basic needs, she says, our brains “evolved to be rewarded by novelty and to find problem solving gratifying.” The brain’s reward system weighs what behaviors are most rewarding. Constantly. And mostly unconsciously. Then it remembers those behaviors and encourages repetition.
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DUHAIME GREW UP PLAYING in the woods in Cranston, Rhode Island, exploring the Pocasset River and spying on birds and turtles for hours. She loved nature’s playground, even though it was a polluted one. A nearby textile mill dumped its dyes into the river, which then ran with whatever colors had been used that day.
Today, Duhaime lives next to 230 acres of conservation land that, she says, satisfy her “need for nature, particularly trees.” At one point, mid-career, she considered becoming an environmental scientist, but the human brain and its mysteries proved too strong a draw, and she chose to stay with pediatric neurosurgery.
After stops at Children’s Hospital of Philadelphia and at Dartmouth-Hitchcock Medical Center in New Hampshire, Duhaime started working at Massachusetts General Hospital in 2010. She spends long days in the operating room, her dark blond hair pulled into a loose braid and tucked under a surgical cap. She cuts out tumors, rearranges malformed skulls, and treats severe cases of epilepsy. But she never lost her need for nature or her desire to protect the planet.
In 1998, Duhaime had an aha moment that changed her life’s trajectory when she read “A Special Moment in History,” an article by environmentalist Bill McKibben published in The Atlantic. McKibben wrote that many might assume changing consumption patterns would be easier than changing the number of children born. “But I would guess that it is easier to change fertility than lifestyle,” he concluded. “We simply won’t live simply enough soon enough to solve the problem.” His argument made an impression on Duhaime because, she says, “it pointed out how critical behavior is in the environmental crisis.” And to understand behavior, you have to go back to the brain.
From watching surgical patients recover one function at a time and studying the brain’s reward system, Duhaime knew that simplification is hard because our brains work on a deeply entrenched, complicated biological level. She also knew personally how challenging simplification could be. Raised Lutheran, Duhaime became a Quaker in her mid-20s and, in keeping with its tenets, tried to pare down her possessions, getting rid of the clothes, appliances, and other goods she didn’t need. It was a difficult process because, she says, “it goes contrary to human nature.” Inspired by McKibben’s article, Duhaime began looking at how to best manipulate rewards to encourage simplification in order to save the planet.
She isn’t the only one to see the brain’s role in environmentalism. Peter Sterling, a neuroscience professor at the University of Pennsylvania School of Medicine, believes life in the industrialized world is out of sync with what human brains had evolved to appreciate: small, unpredictable, variable rewards found in nature. A sustainable future, he says, depends on people finding satisfaction not in stuff but in experiences like trying new sports, listening to new music, socializing, and especially, being in touch with the outdoors through activities like running, hiking, and farming.
“One lesson from neuroscience,” Sterling says in an e-mail from Panama, where he owns a farm, “is that the brain makes new circuits in response to practice. So, some things need teaching and encouragement until the rewards flow naturally.”
Duhaime points out that for the average person, just being told to be or do good doesn’t carry much weight in our brain’s reward system. But, she says, hearing “you’re beautiful, you’re cool, you’re sexually attractive, you’re admirable, you’re better than your neighbors — that’s powerful.”
So, can we make saving the planet about being cool? Not in a hipster farmers-market-make-your-own-pickles kind of way, but in a way that works with the brain’s biology to encourage environmentally friendly rewards until they flow naturally? Some early indications suggest yes and yes.

EVERSOURCE, AN ENERGY PROVIDER in Massachusetts, Connecticut, and New Hampshire, regularly sends out a “home energy report” with colorful bar graphs that let individual households see how their energy use compares with the neighborhood average, and with that of the most energy efficient neighbors. Customers consuming less are rewarded with a smiley-face emoji.
Instead of asking its customers to do something good for the environment, the mailer challenges them to do better than their neighbors. Eversource started this “behavioral program,” as the company calls it internally, eight years ago. The goal: to raise awareness about energy conservation and help customers take control of energy use. Penni Conner, the Eversource senior vice president who oversees energy efficiency programs, says the idea with the neighbor-to-neighbor comparisons was to “tap into folks being naturally competitive.”
By encouraging customers to use less energy, the program saves households an average of $15 per year in energy costs. While that number seems small, when you add up the savings across the region, the impact is significant. Over the past three years, Eversource has sent home energy reports to 1 million customers who have saved a total of $47 million, which translates to a decrease in energy use of nearly 2 percent.
Equally significant, customer feedback and company analytics show habits slowly changing. Conner says customers who receive the reports think more often about buying energy-efficient appliances or getting home energy assessments. In the future, Eversource hopes to understand how different customers respond to different messages about saving energy and create more personalized reports.
What’s Eversource’s reward? With more customers conserving more energy, the company can expand its customer base and still meet demand while the region avoids the need for expensive new power plants.
Consumers’ natural competitiveness also factored into an experiment three researchers conducted with hotels. They didn’t simply ask guests to reuse towels for the sake of decreasing water, electricity, and detergent consumption. They put signs in some hotel room bathrooms announcing that almost 75 percent of hotel customers chose to reuse their towels, and they invited customers to join “Fellow Guests in Helping Save the Environment.” Meanwhile, guests in other rooms saw signs that simply said: “Please Reuse the Towels. Help Save the Environment.” The result: The “towel reuse rate” was nearly 10 percent higher in rooms with the more competitive prompt.
“To make change takes effort and you have to have a reason for it,” says Duhaime. “It helps if you can frame it as something people want.” Think of Tesla: People buy the electric car not simply because they believe it’s better for the environment, but also because it’s high-performing and looks cool.
SO, WHAT’S NEXT? How does a better understanding of the brain’s reward system and its connection to consumption go beyond emojis and towel-use statistics?
“I don’t think neurology is going to provide any answers on its own,” says Dan Schrag, director of the Harvard University Center for the Environment, who admires Duhaime’s openness to fresh perspectives on environmental problems. “Most of the discussions [about getting people to make greener choices]are dominated by psychologists and political scientists and behavior economists and decision theorists,” Schrag says. “Having a neurological perspective challenges assumptions and pushes things in good directions.”
As excited as Duhaime is about her research and upcoming book on behaviors relevant to environmental decline, she knows tapping into the reward system is only one piece of the equation. During a yearlong Radcliffe Institute Fellowship that started in the fall of 2015, the neurosurgeon sketched out an idea for a Green Children’s Hospital, a prototype that would bring nature inside, make sustainability a priority, and shed light on how the structure of the human brain influences the behaviors that impact the environment. She put together an exploratory team of professionals and researchers with the expertise she needed, took her proposal to MGH leadership, and got a starting budget for the project. In April, she received the go-ahead for the next phase — creating more detailed plans.
Duhaime sees the hospital as a test case, a unique opportunity to reframe how businesses approach going green and see firsthand how well it works. Saving the planet might not be the first priority of CEOs, trustees, and doctors envisioning a new hospital. But could installing solar panels and geothermal pumps save enough to appeal to executives who care about financial margins? Could specially engineered countertops that don’t require toxic cleaners offer irresistible benefits to both the hospital CFO and the janitorial staff? Could an on-site garden tended by the patients offer rewards to cafeteria staff by supplying fresh produce? How about to nurses by helping make patients calmer? And what about rewards for patients themselves? Because what kid doesn’t like to play in the dirt. “It’s about aligning behavior with choice with the reward system with environmental impact,” says Duhaime. “Even if the project fails to get off the ground, the basic idea is to investigate what are the limits — or strengths — of hitching environmental goals to things that are known to reward people.”
The Green Children’s Hospital is also an attempt to address the fact that industries — transportation, manufacturing, construction, and health care — account for most of the world’s consumption of energy and materials and the production of greenhouse gases. Duhaime hopes the hospital will provide an opportunity to study what works and what doesn’t with both individuals and organizations.
Meanwhile, at the grass-roots level, there are examples like Holly Rose, who decided to “right-size” her belongings. With help from professional organizer MJ Rosenthal, Rose whittled her book collection from more than 1,000 volumes to 50, gave away extra kitchen items like her spare fondue pot, and trimmed her wardrobe. Now, when she passes her bedroom closet, Rose says, “it makes me feel energized and it makes me feel calm at the same time. I feel I’ve freed up all this RAM space in my brain.”
Decluttering also changed Rose’s shopping habits. She recently visited the new Amazon bookstore at Legacy Place in Dedham. Before paring down, Rose would have bought a book, or five. Now, she thinks Do I really need that? “After you get rid of things, it’s easy to replace them again,” she says. “But I think I’ve gotten good about saying, ‘That’s not what you need.’ ”
Rose found that being free of stuff felt as satisfying as buying more. That’s the brain’s reward system at work in ways that benefit the earth.
And that’s the kind of behavioral change that Duhaime hopes to prompt through a better understanding of the brain’s reward system. Overconsumption “is a short-term high,” she says. “If you don’t understand how your reward system works, it’s hard to avoid the temptation of thinking If I just get this thing, this one thing, I’ll be happy. That’ll be it,” Duhaime says. “But it doesn’t last.”
Shira Springer covers sports for NPR and WBUR and writes a column on women and sports for the Globe. Send comments to magazine@globe.com.