Do Less

The human drive to invent new things has led to pathbreaking achievements in medicine, science and society. But our desire for innovation can keep us from seeing one of the most powerful paths to progress: subtraction. Engineer Leidy Klotz says sometimes the best way forward involves removing, streamlining and simplifying things.

Additional Resources


Subtract: The Untapped Science of Less, by Leidy Klotz, 2021.


People Systematically Overlook Subtractive Changes, by Gabrielle S. Adams, et al., Nature, 2021.

Investigating the Mechanisms of Hoarding from an Experimental Perspective, by Stephanie D. Preston, Jordana R. Muroff, and Steven M. Wengrovitz, Depression and Anxiety, 2009.

Neural Predictors of Purchases, by Brian Knutson, et al, Neuron, 2007.

An Intervention to Decrease Catheter-Related Bloodstream Infections in the ICU, by Peter Pronovost et al., The New England Journal of Medicine, 2006.

Monumental Architecture: A Thermodynamic Explanation of Symbolic Behavior, by Bruce G. Trigger, World Archaeology, 1990.

The transcript below may be for an earlier version of this episode. Our transcripts are provided by various partners and may contain errors or deviate slightly from the audio.

Shankar Vedantam: This is Hidden Brain. I'm Shankar Vedantam. Think about the last time you were part of a brainstorming session.

Clip: We just need to brainstorm five ideas. But to be safe, let's come up with 50. Let's make it 100.

Shankar Vedantam: Maybe this was at work or at a planning meeting for a community organization.

Clip: Just want to emphasize there's no bad ideas here. We're just brainstorming.

Shankar Vedantam: Many people probably suggested ideas. Perhaps there was some discussion about which proposal was best. At the end, maybe everyone voted on the best idea. If your meeting was like most meetings, there was probably one kind of idea that was in short supply: how to do less. I remember a brainstorming session some years ago where colleagues filled an entire wall with Post-it Notes. When I looked at the Post-it wall later on, I was struck that almost none of the notes suggested that the organization could streamline projects, or stop doing things that weren't working. All the ideas were about expansion, new projects. Today we ask why we often ignore one of the most powerful paths to innovation. When less is more, this week on Hidden Brain.

Shankar Vedantam: Humans are curious and inventive creatures. Give us a problem and we will come up with solutions. Usually, this is a marvelous skill. Our drive to invent new things, generate new ideas is responsible for great breakthroughs in science, technology, and medicine. There are times however when our desire to come up with new solutions gets in the way of coming up with the best solutions. At the University of Virginia, Leidy Klotz has long been fascinated by the process of invention and an important component of invention that many of us overlook. Leidy Klotz, welcome to Hidden Brain.

Leidy Klotz: Thanks Shankar. It's great to be here.

Shankar Vedantam: Leidy, when you were an undergraduate trying to master the fundamentals of engineering, you initially adopted an approach to studying that will be familiar to many students. What was that approach and how did it work out for you in your college course on mechanics?

Leidy Klotz: Yeah, so for those of listeners that have enough sense not to major in engineering, mechanics is this branch of physics that deals with objects at rest and in motion. And it requires you to go from plugging numbers into equations to actually visualizing how the concepts work in the world. And my approach to mechanics was the approach that I'd been using in all my courses up to that point, which was okay, figure out how to solve the problems that I've been assigned for homework, learn that specific problem and try to cram as many of those into my brain as possible, so that when the exam came about, I'd be more likely to have an exact replica of the problem that was on the exam already accessible in my brain.

Shankar Vedantam: And how were you doing in terms of grades as the semester unfolded?

Leidy Klotz: I had a C average. It was serious. I was coming into the third exam with the C average and for the first time in my life, I was in danger of failing the course. And if that happened, I would either have to delay my degree progress and ask my parents to pay extra tuition to take the course the following year or change my major to something that didn't require me to pass mechanics.

Shankar Vedantam: So at one point as you were getting these bad grades, you came up with a radical and some might say risky approach for the final portion of the semester. What did you do, Leidy?

Leidy Klotz: I just really stripped away the extraneous things that I was trying to cram into my brain. And this first mechanics class really just boils down to applying Newton's second law of motion. So all of these scenarios can be described by force equals mass times acceleration. And I could derive everything I needed from that equation. And so before that third exam, I stopped memorizing dozens of other equations and tangential ideas. I didn't need to know a bunch of forces and masses and accelerations, I just needed to remember that formula, F equals MA.

Shankar Vedantam: So you try this radical approach, you do the exam and the day comes when the professor's handing out the grades. Paint me a picture of what happens.

Leidy Klotz: Yeah. I'll never forget it. This is Professor Viscomi, just the classic nice engineering professor, but he had this thing where when he handed the exams back, he would write the highest and lowest score on the chalkboard to give you a sense of kind of how the rest of the class did. And so this exam, he comes in and he writes on the board a 98 and a 47. And then he looked at me and smirked. And everybody assumed that I had gotten the 47. My classmates were playfully jeering me and I'm sitting there thinking about like, okay, now that I've failed out of engineering, what will my major be? And when I got my test back, I realized why he had smirked. And it was because I had earned the 98.

Shankar Vedantam: Leidy did better when he focused his mind on fewer things, on core concepts. And it was the start of a long journey to recognize the value in everyday life of removing, of reducing, of subtraction. Some years later, after Leidy graduated, got married and started a family, he had another moment of insight. He was building a bridge using Legos with his son, Ezra.

Leidy Klotz: He was three at the time and we were building a bridge out of his Duplo blocks, the bigger Legos, and the support towers were different heights, so we couldn't span them. They weren't level. And as I turned back toward the soon to be bridge, Ezra had already removed a block from the taller tower. So whereas my impulse had been to add to the short support in that moment, I realized that it wasn't the only way to create a level bridge.

Shankar Vedantam: So this moment captured in a concrete way for you how many of us underestimate the power of subtraction. And I understand you showed other people a replica of Ezra's bridge to see how many of them came up with the idea of taking away a block instead of adding a block.

Leidy Klotz: Yeah. Students would come to talk to me about their assignments and I'd give them this bridge and see what they did. And everybody added like me. And then I also took it to Gabe Adams who's a professor colleague of mine and I thought that I had been talking to her about these ideas, and plus she's like a genius. So I figured, okay, she's the one who's going to subtract here when I give her this. And so I give it to her and she added like me, but then when I said, "Hey, this is what Ezra did." She says, "Oh, so what you've been trying to say is that you're interested in: why do we overlook subtraction as a way to improve things?"

Shankar Vedantam: So Leidy, you became obsessed with the value of subtraction. Some might even say you became a zealot. You started collecting examples from the worlds of engineering and design and you stumbled in the work of the early 20th century architect, Anna Keichline. Tell me her story.

Leidy Klotz: Oh, she's a fascinating person. She was the first female licensed architect in the state of Pennsylvania. She'd played basketball in college, was one of the first women to drive a car. She was also a serial inventor and she made one of the most ingenious advances of the 20th century. And before Anna Keichline, building blocks were solid. So if your house is more than a century old, it probably rests on solid blocks. In her patent, and I think this was 1927, Keichline invented the K Brick, which started to subtract some of the mass from building blocks. What she essentially did was create a hollow block knowing that the load bearing could happen on the outside parts of the block and by creating the hollow block, you remove half the material compared to what was in the typical building block, which of course makes it less expensive and easier to build with and less fuel to transport. And then these hollow blocks also provide more insulation because of the air voids that are in the blocks. So the resulting buildings are more comfortable, less nosy, less prone to fire and the block itself is less expensive. And her subtractive insight it's since gone through several evolutions, but it's led to this building block that's now ubiquitous. It's used to build everything from the facades of schools and skyscrapers to the foundation walls for my two-story addition.

Shankar Vedantam: Once we become familiar with a particular object, we tend to look for ways to add to it rather than to subtract from it. But the act of taking away can produce remarkable results. One of Leidy's favorite examples is an invention known as the Strider bike.

Leidy Klotz: These are the pedal-less mini bikes that basically allow kids as soon as one and a half years old to ride a bike. And the way they work, they're small bikes, but they're not propelled by chains and pedals, but by toddlers striding with their legs. That's why they're called Strider Bike. And what happens is the toddler propels the bike forward kind of like the Flintstone cars. And what's even more impressive is son has since aged out of the Strider bike and once he decided it was time for his big kid bike, we didn't have to bother with training wheels. He already knew how to balance and he just needed to learn how to push the pedals and of course, to break. And children's bikes were marketed as their own distinct class of bicycle for almost a century and there were plenty of design changes over that time, right? Training wheels, fatter tires, more and more speeds, those contraptions that connect a kid's bike to a grownups like a caboose. And it took a really long time for somebody to have the insight of, "hey, will this be better if we subtract the pedals and the drive train?" And when they did think of it, it made these two-wheeled bikes rideable for a whole new age group and saleable to their parents.

Shankar Vedantam: So later you began to ask yourself after seeing these examples how you could apply the insights of subtraction to your own life. And at one point you came up with a novel, approach to a home renovation project. You threw down an unusual challenge to your students, a design contest. You called it "Addition by Subtraction." Can you describe the challenge to me?

Leidy Klotz: Sure. So we moved to University of Virginia and we downsized our home when we moved here ,and the home had also been a student rental. And so we knew that we were going to have to do a renovation. Subtraction was top of mind and I'm an engineer/architect, I guess, by profession. And so I was like, "Can we put subtraction into play here?" And so the name of our contest was "Addition by Subtraction," And I have the great fortune of working with really smart students for whom I ran a design contest. And we emphasized that our goal was to subtract and we even said that we were willing to pay more if the renovation could make a statement through subtraction. And I offered $1,000 in cash and free cookies. And a couple of dozen architecture engineering and environmental design type majors signed up.

Leidy Klotz: And the students came up with clever designs. There was one student who found unused vertical space in our house and used that to add a lofted area to Ezra's bedroom. There was a junior who changed the grading of our backyard and that provided outside access to the basement, which then turned that into a viable living space. And there was this graduate student team that kind of intricately reconfigured the entire floor plan. And all of those things would've made our house more livable. And yet no one had actually subtracted, right? Nobody had taken away a square footage.

Shankar Vedantam: Leidy, at the end of this whole process of invention, what was the end result of your home renovation project?

Leidy Klotz: My wife was worried you would ask. Because now we have a five-room, two-story, 900-square foot edition that extends from the rear of what had been a little Cape Cod.

Shankar Vedantam: Leidy's design contest ultimately failed as a generator of ideas that would lead to subtraction. He discovered that while subtraction might be a powerful driver of invention, many powerful obstacles stand in its way. Understanding those obstacles, and how to overcome them, became his new obsession. You're listening to Hidden Brain. I'm Shankar Vedantam.

Shankar Vedantam: This is Hidden Brain. I'm Shankar Vedantam. Leidy Klotz is an engineer at the University of Virginia. He studies our automatic tendency to add things when it comes to solving problems. After a home renovation project explicitly aimed at subtraction ended up greatly expanding the size of his Cape Cod home, Leidy started to ask why human beings find it so hard to subtract. So, Leidy, at the end of this home renovation project, you were humbled by the process, but it also gave you some important insights into why it is so hard to subtract, to remove, to take away. When it comes to home renovations in particular, one barrier to subtraction was economics?

Leidy Klotz: Yeah. For us, I mean this is the biggest investment our family has and the kind of rule of thumb for home's values, how Zillow calculates it, how the realtors calculate it when they're appraising it, is that the value increases with the total square footage. So 2,000-square foot, that's one price. If you have 2,500 square feet, that's another price. And entrants in the design competition and Monica and I could just never figure out a way past this financial reality. Spending money without adding square footage would've been a really risky investment and spending money to get rid of existing square footage was preposterous. Another thing was it's not that subtracting is always the right option. It has been beneficial to have more square footage in our home. Our family was growing and we did need some more square footage. So this may have been a case where subtracting wasn't the better option, even though we started out with that as our intention.

Shankar Vedantam: And I'm also thinking that presumably they were people - architects and builders and contractors - and they all get paid more for doing more, not for doing less.

Leidy Klotz: Exactly. If we had hired a contractor to subtract space, they're getting paid based on the percentage of how much it costs them to do the renovation. So a less expensive renovation that subtracts space, they get less overhead on that.

Shankar Vedantam: I'm also thinking that expanding during a home renovation is also what's sort of culturally expected, right? How many people do a renovation and end up with a smaller home?

Leidy Klotz: Well, I mean it's right there in the word, right? The synonym for home renovation is a home addition. You never hear of a home subtraction.

Shankar Vedantam: Yeah. So as you started to think about the economic and cultural obstacles to practicing subtraction, you came to understand that such obstacles reach very far back into human history. How so, Leidy?

Leidy Klotz: Certainly in human history, let's start there. This concept of monumental architecture. And again, my background's engineering, I like big structures. I was surprised to learn about how key a role people think or the scientists think monumental architecture played in the development of civilization.

Shankar Vedantam: What do you mean by monumental architecture?

Leidy Klotz: It's literally defined by the fact that it adds well beyond what is necessary. So the principle defining feature of monumental architecture is that the scale and elaboration and detail exceed the requirements of any practical functions. So the ziggurats in Mesopotamia, the pyramids of Egypt and China, these massive but marginally useful structures kind of grew at the same time as the cities around them.

Shankar Vedantam: And even today, you could argue that in a modern world, people are rewarded in terms of resources and status when they add as opposed to when they subtract. We have markers and plaques for the people who build skyscrapers, not for the people who take them down.

Leidy Klotz: Exactly. That's a huge challenge on university campuses, for example, right? It's so much easier to get a donation for somebody to create a building that has their family's name on it than a donation for removing something or even for something that doesn't come with this big physical reminder of the person's generosity.

Shankar Vedantam: It makes sense that donors want to put their money behind something tangible. Politicians similarly want to be able to cut a ribbon to tout a new amenity that they're delivering for their constituents. It's hard to cut a ribbon on an empty field. These are the sorts of cultural and political forces that subtly push us to favor addition over subtraction.

Leidy Klotz: Across all of these examples, the problem is that subtracting is more work. It's more mental work. It's more kind of steps as we're talking about it, and there's less to show for it. And so after you do all this extra work, you have less evidence because the thing that you've done has by definition disappeared.

Shankar Vedantam: So I understand that your employer, the University of Virginia, once asked for suggestions on how the university could be improved and you ended up analyzing the recommendations that came in. What did you find, Leidy?

Leidy Klotz: Yeah, we had a new latest strategic planning effort with a new president and it's began, as these tend to, by soliciting ideas from students, faculty, staff, community, alumni members, donors, and all of them were basically offering their ideas for how to improve the university. We got our hands on the data and as expected, the adding was rampant. People wanted more study abroad grants, more mental health services tailored to international students, more housing options. There was a request for a new ice arena. And I didn't know we had an ice hockey team here, but I'm assuming that's progress too. But the thing is surely there was untapped potential because out of 750 ideas for changing the university, fewer than 10% suggested taking something away.

Shankar Vedantam: Yeah. I want to turn my attention to what happens within organizations when we are having brainstorming sessions around a table, for example. I feel like there's often a lot of pressure to add and almost no incentive to subtract. So everyone sitting around the table wants their idea implemented. Polite people don't want to shoot down ideas from their colleagues. And so the net result is a pile up of new programs, new projects, a ton of additions.

Leidy Klotz: Certainly. There's politeness and then there's also just, it's kind of a good decision making shortcut to not come in and say, "Oh, here's something we definitely should subtract from this organization" until you understand how the organization works, right? So it's pretty bold for somebody to say, "Hey, let's get rid of the ice hockey team" before you understand what they're contributing to the university, the history of the ice hockey team and so on and so forth. To add something, you can just say, "Well, this would make anything better. So let's add it to our system that I don't really understand."

Shankar Vedantam: I understand that you've also looked at how adding could even have biological roots. Tell me about the work of Stephanie Preston.

Leidy Klotz: Yeah. Stephanie's one of my favorite researchers. She's a psychologist at the University of Michigan and she knows more than anybody about what she calls acquisitiveness, which is how and why we get and keep things. So for example, one of my favorite studies of hers, participants are shown more than 100 different objects in random order and one at a time. And then as each object appears on the screen, participants are asked whether they would like to acquire it virtually. It's all imaginary. They know they won't actually get these things. And they can acquire as many or as few as they want. And the objects vary in their usefulness. So there are things like bananas and coffee mugs and extension cords, things you might pick up. Others seem less useful, but people do still pick up like empty two-liter bottles, used sticky notes, outdated newspapers. And once they have made a choice about each of these 100 objects, participants are then shown everything that they've added. So if you've acquired 70 things, you're shown all 70 things together on the screen and then you're encouraged to subtract. Then they're challenged to whittle down their collection, so that it can fit into a shopping cart on the computer screen. And finally, they're asked to make it even smaller so that it can fit into one virtual paper grocery bag. So the goal is very clear. Everything needs to fit into one grocery bag or else you don't complete the task and you're getting real time feedback displayed on the screen of whether you've subtracted enough stuff. And a lot of participants fail to get it down to a single bag and many don't even make it past the shopping cart.

Shankar Vedantam: I understand there's also been research into what happens inside the brain when we engage in addition or engage in subtraction. What does that research show, Leidy?

Leidy Klotz: One way that the neuroscientists have studied this is hooking people up to their brain imaging machines while they're acquiring things. And so food acquisition as well as other types of acquisition activate this same reward system in the brain. So it's this pathway connects basically the thinking and the feeling parts of our brain, and this is what makes it pleasurable to eat. And it can also be stimulated, as we know, by drugs like cocaine, website designs that keep us clicking and scrolling, and then for hoarders, even the used sticky notes can kind of stimulate this reward pathway. And so when you do find that a specific reward system like this one is playing a role, it confirms just how deep-rooted some of our tendency to add might be.

Shankar Vedantam: So you've also conducted a whole bunch of experiments and reveal what you call subtraction neglect, our tendency to ignore the power of subtraction. And one of them was inspired by a long-running debate you've had with your wife when it comes to travel. Can you give me a concrete example of this debate in action, Leidy?

Leidy Klotz: Well, so yeah, we go to the Outer Banks sometimes, and that's the islands off of North Carolina. And so your day can look something like going to look at Kitty Hawk and see where the Wright brothers did their thing and go see some sand dunes and you can go out to eat and you could drive down and look at all the lighthouses. Or you could kind of just let the day come to you and maybe do some looking for shells on the beach and see what happens for lunch and have a less scheduled day there. And so I prefer the latter kind of vacation. My wife, Monica, likes to pack in as many activities as possible.

Shankar Vedantam: And I understand that you've actually run studies perhaps based on this marital dispute you've been having when it comes to how people think about travel. Tell me about those experiments, Leidy.

Leidy Klotz: Well, it's not a dispute. She's right, right? So it's not. But this is worse than even anything Monica would schedule. So we created this itinerary for a day spent in Washington, DC. So now we're back in the experimental world again, and over the course of 14 hours, this itinerary had participants visiting major tourist sites like the White House, the National Cathedral, the Old Post Office. And then have them paying their respects at the various memorials like the Lincoln and the Veterans Memorial. And then a museum visit, shopping, and lunch at a five star bistro. So just travel time between all these stops would exceed two hours assuming optimal D.C. traffic, which never happens. Participants saw this original itinerary and then like kind of a drag-and-drop interface on the computer screen and they could change their itinerary by rearranging, adding, and subtracting activities. And even with this jam-packed itinerary, only one in four participants removed activities from the packed original.

Shankar Vedantam: Wow. And what did the rest do?

Leidy Klotz: Well, some rearranged, but most added.

Shankar Vedantam: They added to this itinerary? How is that even possible?

Leidy Klotz: It isn't. There's not time, but it was possible to kind of collect something, drag and drop another task, and it was enticing when they saw the other tasks sitting in there on the side. I think they were thinking, "Oh, look, that would be a fun thing to do." And it's kind of the same as the strategic planning. You think, "Okay, adding more good stuff is always good." And in this case, it was just going to make the overall schedule even more impossible and more crowded and less pleasant.

Shankar Vedantam: There's another study you conducted that was inspired by a difficulty you encountered in your own writing. Tell me about the challenge that you have faced in your own writing and the study you conducted, Leidy.

Leidy Klotz: Anybody who spends time playing with words on paper or on a screen has heard the advice, right? Strunk and White, they're the most assigned textbook on college and high school syllabi and their classic advice is: omit needless words, that editing is the way to make your writing more clear. And yet that's very obviously a form of subtracting, right? You're taking something that you've created and now you're taking things away from it. So we gave people a summary of an article and said, "How would you make this better?" And only 17% ended up subtracting words from the original. So by and large, they added to make the summaries better.

Shankar Vedantam: And I understand the same thing applies when you look at how people think about recipes, for example, how they're cooking. The same idea, addition rather than subtraction.

Leidy Klotz: Oh yeah, we found this in so many contexts. People improving a five ingredient recipe, two out of 90 participants subtracted. When they transformed loops of musical notes, they were more likely to add notes than to take them away. So we found this across many different contexts.

Shankar Vedantam: When we come back, techniques to battle the obstacles that stand in the way of subtraction. You're listening to Hidden Brain. I'm Shankar Vedantam.

Shankar Vedantam: This is Hidden Brain. I'm Shankar Vedantam. Engineer Leidy Klotz is convinced that our world would be a better place if we engaged more often in subtraction instead of always choosing to add. The problem is there are many psychological obstacles to subtraction. There are times however when opportunities for subtraction open up and Leidy says smart people and smart communities seize on such opportunities. Leidy, tell me the story of San Francisco's Embarcadero Freeway.

Leidy Klotz: Yeah. Like so many other city crossing highways in the United States, the Embarcadero Freeway was built after World War II and it was made possible by federal support for highways to move the military and serve the growing number of automobiles. It stretched for more than a mile along the eastern waterfront and it blocked precious views and access to the bay. And so planners started to think, "Well, is this costing more than it's adding?" And finally the planning commission said, and this is in the mid '80s, "We should get rid of the Embarcadero Freeway."

Shankar Vedantam: And what was the public reaction to this?

Leidy Klotz: Not good. But this one actually got put to a vote and it wasn't even close. For every voter in favor of removing it, there were two who wanted to keep it. And whether it was for fear of traffic, fear of lost business, fear of change, voters rejected it. And the people had spoken. So the planning commission basically moved on and focused on other projects.

Shankar Vedantam: So following the 1986 vote, it seemed that the possibility of tearing down the freeway and opening up the waterfront was dead. And then something happened on October 17th, 1989.

Ted Koppel: I'm Ted Koppel. There has been a rather strong earthquake in Northern California, so strong in fact that it has among other things, knocked out all the power at Candlestick Park where the third game of the World Series was being played. But in the overall scheme of things, that may be the very least of things that has happened today. Let me show you a piece of video that just came in.

Shankar Vedantam: So this was the Loma Prieta earthquake. And of course, the earthquake was a terrible thing. It caused a lot of damage, but it may have had one unexpected benefit: it changed how people thought about the Embarcadero Freeway. How so?

Leidy Klotz: Well, a number of ways. So the earthquake killed more than 60 people and injured thousands. A lot of the deaths actually happened on a similar double-decker highway, the Cypress Street Viaduct in Oakland. So people seeing this double-decker elevated concrete structure just over a mile in length, it looked ominously like the Embarcadero. And then it also gave people a view of what life would be like if you didn't have the Embarcadero because the Embarcadero didn't collapse during the earthquake, but it was rendered unusable for a while. And so people saw that they found other ways to get around the city and that it didn't kind of totally ruin life in San Francisco to not have the Embarcadero.

Shankar Vedantam: And then what finally came of all of this, Leidy?

Leidy Klotz: It still wasn't...this was by no means a unanimous choice. There's a famous Pulitzer Prize-winning San Francisco Chronicle columnist. His name's Herb Caen and he's such an influential columnist. And even after the earthquake, as people brought this discussion back up, he has this great quote. "Once again, there's serious talk about tearing down the Embarcadero Freeway - an even worse idea than building it." And so there was still resistance. But eventually the freeway came down. And when it was removed, they got the waterfront back, they saw an increase in housing, increase in jobs, it didn't cause traffic nightmare, trips were rerouted. And if you've ever visited there, it's one of the most visited places in the world and it's obvious why it shouldn't be covered with the freeways. So it took about 10 years, but by 2000, kind of the 10 year anniversary of the demolition, the Chronicle was then reporting that it was hard to find anyone who thinks ripping down the freeway was a bad idea.

Shankar Vedantam: So we've had a crisis of our own the last couple of years that have forced a lot of us to think about what we do, where we work, how we work. How might the COVID-19 pandemic serve as a potential driver of subtraction, Leidy?

Leidy Klotz: Yeah. I think at horrific cost, it's given us this singular chance for change and forced us to subtract in ways that we never would've managed on our own. And certainly, I don't advocate subtracting family visits and friendly hugs, but we've also had to get rid of kind of things that I don't mind if they don't come back. Things like buffets and commutes and evictions, and even carbon emissions. So I think that the crises interrupts this normal flow of things and shows us what a world with some of these subtractions might look like.

Shankar Vedantam: Isn't it interesting that so often we actually need the external push before we see the value in subtraction? We've talked about earthquakes, we've talked about a pandemic. You can think of a forest fire the same way. It's obviously not a good thing when you have a forest fire, but the removal of old growth might be helpful for new growth to happen in a forest. When I'm thinking about the marketplace for example, businesses go out of business, stores go out of business because they kind of track customers or they're selling stuff that people no longer want. And of course, it's painful if you happen to be the store owner whose business is going bankrupt, but the net effect of this is that it gives another business a chance to spring up. But in each of these cases, it's interesting that we almost need the external force in order for us to see the value of subtraction. It's so emotionally difficult for us to do the subtraction ourselves that we need almost an external executioner to come in and do the hard stuff for us.

Leidy Klotz: Yeah. Emotionally and cognitively difficult. And even if you look at evolution as a metaphor, the way that it works is through adaptation and then selection. So adaptation is an add and then the selection is a subtraction and they're working hand in hand.

Leidy Klotz: And I think another fundamental disadvantage that's coming into play here is that we don't get as many reminders of subtraction, right? Because when something is added, there it is right in front of you as evidence that adding this thing was a way to make change. If something was subtracted in the rare cases that we do it and follow through with it, it's by definition gone. So as we walk around in the world, we don't have these external reminders that, hey, here's this subtraction. It's also a good way to make things better.

Shankar Vedantam: The things we subtract are often invisible. We don't notice them or we quickly become used to their absence. And so we fail to appreciate how these innovations, like Anna Keichline's building blocks, are affecting our lives. But sometimes inventors can find clever workarounds to this obstacle. Back in the 1970s, an aerospace engineer named Marion Rudy came up with the idea of using air to provide cushioning in running shoes. It was a classic moment where less added up to more. But there was a problem. You couldn't actually see this innovation in action. It was inside the shoes. Marion Rudy kept bringing the idea to shoe companies and they kept turning him down.

Leidy Klotz: He finally got to Nike, which at the time was kind of this boutique outfit that just served elite runners. And as the story goes in Nike lore, Phil Knight took him out for a run, liked what he felt, and then air went into the Nike shoes. But even after the air was in the shoes, nobody could see it, but the Nike really started to take off. They had this seminal shoe, the Air Max 1, and those shoes were one of the first models that actually displayed the air. So they have the little window on the side so you could see, hey, in fact, there's air in here. And that made the subtraction noticeable and it was something that made Nike shoes different from any other kind of shoe and kind of helped launch them on the path that took them to where they are today. Of course, there's a guy named Michael Jordan who helped.

Shankar Vedantam: So we've looked at how external crises can sometimes be a driver of subtraction and how increasing the noticeability of subtraction, the value of subtraction, can help us embrace subtraction. You've also thought about other systems in some ways that can incentivize people to focus on subtraction. Tell me about your stop-doing list, Leidy.

Leidy Klotz: A stop-doing list is essentially the same as a to-do list except for you're thinking of things that you're not going to do anymore. And how I use it is whenever I do my to-dos, which I try to do on a weekly basis, I also force myself to come up with equivalent number of stop doings, which kind of makes sense, right? If you're going to add new stuff to your day and assuming you're already at capacity, you need to also figure out what you're going to take away.

Shankar Vedantam: Are there any specific things on your stop doing list that you have? I'm curious in terms of your stop doing list, what are the things that you put on?

Leidy Klotz: One that's been really helpful for me is basically a stop-editing. I read a lot of my students writing and it can be really tempting to just go through and make all of the changes that I would want to make. But of course, that's not really helpful to them. And so like I'll set a limit. I'll say, "Okay, give this student the 10 most important comments for this piece of writing." And it works really well. It saves me time, one, but it also kind of rewards students who do more, right? So if the student gives you a really polished piece of writing, I still force myself to come up with 10 ways to make it better whereas if somebody doesn't put as much time in and gives you this really rough first draft, I don't spend all my time getting that to the same place that the other piece of writing is. Another example is just meetings. Meetings are the classic thing where I am providing some marginal value by attending a meeting or by calling a meeting, but not considering what could be done in that time. So I think often times my stop doings are directed at meetings that I'm attending, but also the ones that I'm calling and asking other people to attend for me.

Shankar Vedantam: Can you talk a moment about the role of subtraction in public policy? When we think about legislators, for example, we think about legislators as people who make laws, whereas you might argue that a crucial part of what legislators ought to be doing is pruning back laws that might no longer be useful.

Leidy Klotz: Yeah. I did some digging into how much laws have grown over time and by some measures they've grown even faster than our economy. So it's just like all these things have this adding trend and laws are no exception. And it's the same as the building of civilization. When you don't have roads, it makes sense to add them, but once you've kind of been adding roads for a while, there are more opportunities to take them away to reveal pristine water. And so the laws, we've kind of accumulated, accumulated, accumulated, and we're left with a bunch that are redundant. And so some places have actually required legislators to when they come with a new law also come with two that are on the books that they want to get rid of. And that kind of rule can be really helpful. It's saying, look, you're a competent legislator if you do this.

Shankar Vedantam: Leidy has been struck by the fact that subtraction can play a surprisingly powerful role in medicine. Doctors and nurses often have so much going on that simplifying rules and reducing complexity can actually improve patient outcomes.

Leidy Klotz: Yeah. My sister's a medical doctor and she was actually taught by this guy, Peter Pronovost. And what Pronovost was interested in was improving the practice of inserting central line catheters. So these are those thin plastic tubes that are used to draw blood or administer fluids and medication.

Shankar Vedantam: Catheters are ubiquitous in American hospitals and they're also one of the most common sources of infection.

Leidy Klotz: And it's not a sexy topic certainly, but these infections were actually causing about 30,000 deaths each year in the United States, roughly as many as car accidents. And it's a complicated process. There are dozens of steps requiring thought and judgment and skill and it's different based on the person. If you've got a 10 year old who's dehydrated, it's a different process than inserting one on a concussed offensive lineman, for example. But to prevent the infections, Pronovost and his team considered all of this complexity, but then they proposed a very simple recipe. They gave a checklist and it's that medical professionals would wash their hands with soap, clean the patient's skin with antiseptic, put sterile drapes over the entire patient, wear a sterile mask, hat, gown, and gloves, and put a sterile dressing over the catheter site. And those very simple steps have brought striking results. It's almost entirely eradicated catheter infections and it saved thousands of lives.

Shankar Vedantam: We've talked at some length about how addition is psychologically pleasurable and subtraction is often psychologically painful. One of your really interesting insights is that we should all try to reframe losses, subtractions, as additions. And there's an author you like who preaches this message. Here's the clip of her.

Marie Kondo: The important things about tidying is not choosing things to discard, but choosing things to keep. So how do you choose what to keep? Is the item spark-showing? Keep it. It does not, get rid of it.

Shankar Vedantam: I take it you're a fan of the tidying guru Marie Kondo.

Leidy Klotz: Yeah, a reluctant fan. As a professor, I felt like, oh, I can't be a Kondo acolyte, but talking about our research, people would keep bringing her up. So I said, "I got to figure out what she's writing about." And of course her tone and observations, advice are very spiritual, but through trial and error in this her specific context, tidying, she's derived some tips that are pretty scientifically sound. For example, her core message is sparking joy. Default home organization advice is like get rid of the stuff you don't want, that doesn't fit. And she flipped it around. She said, "Keep what sparks joy and get rid of everything else." And so she's kind of steering us around loss aversion there knowingly or not because she's focusing us on this future vision of the tidy space. And sure it's a little painful to get rid of these individual things, but you're just thinking of them as one component that's going to improve the overall situation.

Shankar Vedantam: I understand you've also looked at artists, writers, musicians, painters who've also thought deeply about subtraction. What have you found, Leidy?

Leidy Klotz: It's hard to find an expert who doesn't have some counterintuitive or seemingly counterintuitive advice on how to subtract, right? So Picasso defining art is the elimination of the unnecessary. And then you've got The Little Prince's author saying "Perfection is achieved not when there's nothing more to add, but when there's nothing left to take away." We talked about Strunk and White omit needless words. This goes way back. You've got William of Ockham of Occam's razor fame and his quote is, "It's in vain to do with more what can be done with less." And then a quote that gets attributed to Lao Tzu, "To attain knowledge, add things every day. To attain wisdom, subtract things every day." And that's two and a half millennia back. And I think I learned a ton from these new and old prophets of subtraction, but the main takeaway is that they're the exceptions proving the rule, right? Their advice endures because we are still neglecting subtraction.

Shankar Vedantam: I want to play you an excerpt from a song from an artist you admire. (singing) Leidy, tell me about Bruce Springsteen's celebrated album, Darkness on the Edge of Town.

Leidy Klotz: He's my favorite musician. And I think I love Darkness on the Edge of Town as an example of persistent subtraction. So there are 10 songs on the album, the one you just played, Darkness on the Edge of Town, being the title track, but he recorded more than 50 songs during this time just to get those 10. And these are not bad songs that he cut, but some of the ones he cut became hits instantly for other artists. So Patti Smith's Because the Night, that got to number 13 on the charts. He gave a song, Gary U.S. Bonds' This Little Girl, that hit number 11 on the charts. The Pointer Sisters' Fire, which hit number two on the charts, that's a Bruce Springsteen song and a thing that he didn't think was good enough to go on Darkness on the Edge of Town. And now we know Bruce Springsteen is this incredibly successful musician, but the audacity at the time, he had yet to have a top 20 single of his own and he gave away three singles off that became top 20 hits for other artists.

Shankar Vedantam: And what do you think he was after doing this kind of extreme culling?

Leidy Klotz: He has a great description of it in his autobiography, Born to Run, which is just an amazing autobiography. He talks about this album as his samurai record, all stripped down for fighting. And those are his exact words. So he was going for this really stripped down aesthetic than he had had on any of his previous albums and that he thought would kind of revolutionize the way music was heard.

Shankar Vedantam: I understand that one of these songs has a special meaning for you and your son.

Leidy Klotz: Yes. My absolute favorite song from that album will always be Racing in the Street. And that was Ezra's lullaby for as long as he needed them. He doesn't need them anymore. And it's a very stripped down song. The first line of it is "I got a '69 Chevy with a 396." And that's illustrative of the sparse lyrics that are present all the way across Darkness on the Edge of Town. And this is really a transformation for Springsteen because the opening line to the first song on his debut album, Greetings from Asbury Park, it's the song Blinded by the Light, which... Here's the opening line, "Madman drummers bummers and Indians in the summer with a teenage diplomat." So he's perfectly capable of this meandering Dylan-esque prose and now he's going to Racing in the Street, "I got a '69 Chevy with a 396." (singing)

Shankar Vedantam: Leidy Klotz is a professor of engineering at the University of Virginia. He's the author of Subtract: The Untapped Power of Less. Leidy, thank you for joining me today on Hidden Brain.

Leidy Klotz: Thanks so much for having me. (singing)

Shankar Vedantam: Hidden Brain is produced by Hidden Brain Media. Our audio production team includes Bridget McCarthy, Annie Murphy Paul, Laura Kwerel, Kristin Wong, Ryan Katz, Autumn Barnes, and Andrew Chadwick. Tara Boyle is our executive producer. I'm Hidden Brain's executive editor.

Shankar Vedantam: Today for our unsung hero segment, we bring you a story from our sister podcast, My Unsung Hero. A few years ago, LaQuista Erinna's six year old son, Jackson, was diagnosed with autism. This wasn't a surprise. Ever since he was a baby, she had noticed he was overly sensitive to everyday things: textures in his clothes, light touches, loud sounds. Haircuts were the worst. He'd gets so anxious that he'd start kicking and screaming. It was really hard for LaQuista to watch, so she decided to stop taking him.

LaQuista Erinna: This is so traumatic for my son. Why am I continuing to put him through this? And so we went almost two years with no haircuts, people making comments. You need to get his cut. Why your hair looks like... People just say all kind of rude things.

Shankar Vedantam: Eventually, LaQuista found a barber named Ree. For the past few years, Ree has been able to take things slow with Jackson and learned how to stave off his meltdowns until one day in early 2022 when things went wrong.

LaQuista Erinna: We were running late. We got caught in traffic. He left his headphones. We hadn't had lunch. It was just like a series of unfortunate events. And he's like, "No, I don't want to go." I was like, "Come on, Jackson. Stop playing. I got things to do. I'm hungry myself." I have to say it like three times. And this time he refused to get in the seat and he started running around the shop and Ree is like, "Come on, Jackson. Man, you know you my man." She's trying to talk to him. She tried to put the cape on him and he just had a fit. And she was like, "Come look in the mirror. I'm going to show you what I'm doing." And he looked, but he still wasn't having it. And I was like, "Come on, Jackson. I'm getting frustrated." And she was like, "No, I got it." And so I just sat on the couch and I'm like, "She's not going to be able to cut his hair. I'm going to give it five minutes. We're going to go get something to eat and go home." Well, next thing you know, I'm looking and she's cutting his hair. He's standing up. And I'm like, "Wait, she's playing a game with him." She would shave his hair, the hair would fall, he would wipe it off, and then they would run to a different spot because he doesn't like the hair to get on him. It's like a whole thing. So it was a good distraction for him and she was able to cut his hair. When they got finished, he was so happy and he was like, "Well, can we come back tomorrow and play the game?" I was like, "I don't know about tomorrow, but we'll be back in a couple weeks." Jackson and Ree, they have their own special relationship. And I think most importantly, he trusts her. He will not let anyone else touch his hair. And that just goes to show like how she nurtured that relationship. This has been a really tough year for Jackson. The last couple years have been really challenging from starting pre-K and then now transitioning to kindergarten and then a new school. So when Ree was able to do this and just accommodate him, it meant the absolute world for me to be able to trust her and be like, "Okay, I know she's going to take care of my son and make sure he's looking the best." You can't ask for anything more than that. I just want to tell Ree that we love you. You are part of our family now and you'll never fully understand how much this meant to me as a mom.

Shankar Vedantam: LaQuista Erinna. LaQuista took a video of Ree that day calming Jackson down with the haircutting game and posted it on social media. That clip now has millions of views. If you enjoyed today's conversation about how to innovate through subtraction, please be sure to share it with a few friends. Another way to help the show is through financial contributions to our work. You can make a donation in any amount at Again, that's I'm Shankar Vedantam. See you soon.


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