Imagine you confront this problem. You want to build a house in the Rocky Mountains of Colorado, where winter temperatures sometimes dip to –40 degrees Fahrenheit. Your house can use only renewable energy, and it has to cost less to build than one powered by fossil fuels. Oh, and it needs to have a room that is warm enough to grow bananas year-round.
Most people would begin to think about solutions by shopping around for the necessary materials but not Amory Lovins, the renowned energy efficiency advocate. Lovins came across a counterintuitive answer to his indoor farming needs. He chose not to add new design features but rather to omit some of the ones that would be found in any standard architectural plan.
Lovins was an outlier. My colleague psychologists and I have found across dozens of studies that people’s first instinct when asked to do something like create a carbon-zero banana farm is to add on to what is “already there.” It seems like we are programmed to add rather than subtract.
In one of our studies, for example, we asked participants to imagine themselves as the assistant manager of a miniature golf course. They were shown an aerial view of one of the course’s holes and asked to “make a list of all the different ways that you might be able to improve the hole without spending a ton of money.”
Our miniature golf hole could be improved by subtraction. A hypothetical assistant manager who wanted to make the hole more challenging could remove the corner bumper that golfers can use to make it around the turn in one shot. An assistant manager who wanted to make the hole easier could remove the sand trap. Note that subtractive changes would, on balance, better satisfy the instructions to save on costs.
Study participants listed their ideas for ways to improve the hole, which we then classified as additive (“put a windmill in the fairway”), subtractive (“remove the sand trap”) or neither (“switch the hole and the tee locations”). As with the other scenarios, my colleagues and I have studied—whether in writing, scheduling, building with Legos or creating symmetrical patterns from random grids on a computer screen—few participants chose subtraction as a solution. Among the 338 people tested with these simple instructions, only 90 provided a single subtractive idea in their list of all possible improvements to the miniature golf hole. By contrast, additive solutions abounded.
Systematically overlooking a basic way to introduce change is itself troublesome in our approach to problem-solving. By overlooking subtraction, we miss ways to make our lives more fulfilling, our institutions more effective and our planet more livable. We pile on “to-dos” when we really need “stop-doings.” We create incentives for good behaviors but don’t get rid of obstacles to them—and we overlook ways to make indoor banana farms in the Rocky Mountains on the cheap and using no fossil fuels.
Well, at least most of us do. Let’s return to Amory Lovins. He is a trailblazing designer who has earned almost every major environmental award, a place on Time’s list of the 100 most influential people and (unbeknownst to him at the time) a spot on my personal Mount Rushmore of intellectual influencers. So when Lovins e-mailed to “send cheers” for my group’s work on subtraction and share his own real-world example of the power of taking away, I only wondered which of his brilliant designs he would choose.
To make his home in the Rockies, Lovins came up with a number of additive ideas. He affixed solar panels to capture energy from the sun and added the very best insulation to keep the warm inside air separate from the wind and cold air outside. He added high-performance windows to allow banana plants access to light but not cold. For the engineers reading, yes, Lovins added special ventilation heat recovery systems. Combined, features such as these satisfied the indoor -banana-farm and no-fossil-fuels parts of the puzzle.
Had Lovins stopped there, he would have been left with a home that cost more to build, not less. To rein in expenses, he came to realize that all of the added efficiency allows the home to be heated entirely by the sun—through the windows, plus the heat of lights and appliances (themselves very efficient), body heat and maybe “a 50-watt dog.” This meant Lovins could do more than run the mechanical heating system on renewable power. He could get rid of it altogether. The efficiency that eliminated the heating system would be paid for up front by elimination of the heating system. Lovins’s subtractive insights were not destined for his house alone. They have saved on costs and enhanced performance all over the world. Lovins’s approach of both adding and subtracting features has inspired hundreds of thousands of “passive homes” like it, mostly in Europe.
How can the rest of us then take these examples and harness routinely the untapped power of subtraction? Or, as Lovins had e-mailed to ask, “How can we overcome and remedy the innate and trained bias toward additive solutions?”
Zoom teleconferencing with Lovins, with the banana farm in the background, we discussed what I had learned over the course of my research. My studies had identified a new part of the problem, and my new book Subtract was a years-in-the-making scientific take on what we can do about it. For one, people can recognize the value of subtraction if they are made aware of the opportunity. In some of our studies, participants had been randomly assigned to receive cues that subtraction was an option. In the miniature golf setup, for example, no-cue instructions did not mention either addition or subtraction, whereas the cued instructions reminded participants of both: “Keep in mind that you could potentially add things to the hole as well as take them away.” This simple directive more than doubled assistant managers’ rates of subtraction. And while the cue also mentioned addition, it did not change the rate of this type of alteration.
Because the cue increased subtraction but not addition, we can surmise that people were already considering additive solutions, whereas the subtractive part of the cue brought new possibilities to mind. This finding suggested that part of the reason we so often choose to add is because we don’t even consider subtraction. For the discussion with Lovins, this finding suggested a simple remedy. To find solutions that involve subtraction, we need cues.
“Omit needless words” is a writing cue from The Elements of Style. “Discard anything that doesn't spark joy” is a closet cue from Marie Kondo. “Subtract things every day” is a wisdom-pursuit cue from Lao Tzu. To share his design wisdom, Lovins developed principles, some of which hint at taking away. Principle 10 is to “start with a clean sheet,” which might prompt us to question the need for a heating system. Principle 13 is to “seek radical simplicity,” which reminds us to strip away parts, perhaps even heating systems, that become unnecessary. And to build a cost-effective indoor banana farm in the Rocky Mountains, it may help to consider Principle 14: “Tunnel through the cost barrier,” which refers to how Lovins continued adding slightly costlier efficiency measures—“tunneling through” until he could subtract the really expensive heating system.
Zooming with me, Lovins mused that his design principles could be more explicit in cueing subtraction. He could edit down the principles themselves or reorder them to suggest subtraction even before addition. Whatever he decides to do, I’ll remember the last line of his e-mail as an all-purpose cue: “Go forth, and be fruitful, and subtract!”
This is an opinion and analysis article, and the views expressed by the author or authors are not necessarily those of Scientific American.