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Nudge

13 Jul 2026 · 20m · 7 chapters

Episode artwork

88 out of 90 people fall for this bias. Do you?

In short

Humans default to “addition” (adding blocks/ingredients/words/reasons) even when “subtraction” would improve outcomes; subtraction can also create persuasion and competitive advantages.

Guests

Leidy (Lydie) Colts, professor in Engineering and Society at the University of Virginia; author of Subtract. Richard Shotton, marketing behavioral-science specialist (appears as a prior guest referenced). Todd Rogers, Harvard professor (referenced via an interview).

Key claims

In experiments, most people add rather than remove (88% added Lego blocks; 88/90 added soup ingredients). Adding multiple benefits dilutes credibility (gold dilution effect: tomatoes framed with two benefits rated ~12–13% less effective for cancer). Concise persuasion beats longer messages (Todd Rogers: 49-word email ~2x response rate vs 127-word). Stress/distraction increases additive bias.

Notable examples

Lego bridge balancing; improving five-ingredient soup; “Subtract” sticky-note in The Bear; Five Guys’ short menu; cardio exercise framed with one vs two benefits; Nike/Adidas/ASICs blog examples; school-board email word count.

Written by AI. May contain mistakes.

Chapters

0:00

The Lego Bridge Problem

Explore the common bias towards addition in problem-solving through a Lego analogy.

“In front of me right now I have a Lego bridge.”
3:00

The Addition Bias in Cooking

Discuss how the bias to add extends to cooking, affecting people's choices.

“While teaching at Virginia, Leidy wrote Subtract.”
4:55

The Gold Dilution Effect

Learn about the Gold Dilution Effect and its implications on perception.

“because they took on Lydie's advice and subtracted from their offering.”
9:03

Subtraction as a Competitive Advantage

Discover how subtraction can give brands a unique market edge.

“Subtracting makes cardio seem better for you.”
11:21

Conciseness in Communication

Learn why being concise can lead to more effective communication.

“You're listening to Nudge with me, Phil Agnew.”
14:00

The Power of Subtraction in Decision Making

Learn how simplifying choices can lead to better decision outcomes.

“like, oh, obviously the longer one that is more deferential and expresses more gratitude will be more effective.”
17:22

The Power of Subtraction in Decision Making

Learn how simplifying choices can lead to better decision outcomes.

“Well, thank you so much for listening to today's episode of Nudge, folks.”
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Transcript

Automatic transcript. May contain errors.

0:02In front of me right now I have a Lego bridge. The bridge is very simple, this is not a complex piece of Lego. There are two long pieces connected together that form the bridge span, that's where the drivers and the pedestrians would drive and walk across, and then there are columns on either side of the bridge to form the foundations, the foundations that lift it above the river below. However, on the left side of the foundation, I have three pieces stacked on top of each other. On the right side, it is just two pieces stacked on top. My goal is to make the bridge level. How should I do it? Ask yourself, what would you do?

0:43You've got three pieces on one side, two on the other. What do you do to make the bridge level? You've got a pile of other Legos sitting next to you. What do you do? This exact problem inspired today's guest on Nudge to write his critically acclaimed book. This is the basic issue that we had with my three-year-old son at the time. And it's like, how do we make this bridge level? And of course, I turned around behind me to grab a block to add to the shorter column. And by the time I had turned around, he had removed a block from the longer column. Most of us, most adults at least, immediately think about addition.

1:14We think about how we should add a block to fix the problem. My guess is that most of you thought the same way when we introduced the problem at the start of the show. because today's guest on Nudge has studied this exact scenario. Alongside his three colleagues, he recruited participants and gave them a slightly bigger bridge. It had eight or ten blocks at the base. When asked to balance the bridge, 88 % added a block, only 12 % removed a block. When we're presented with a situation, whether it's a Lego bridge or an essay or a podcast episode or your calendar, our first instinct to try to make it better is to add something to it.

1:56But often addition doesn't make something better. In many cases, especially in marketing and especially in business, it makes your offering worse. We'll explain how in today's episode of Nudge.

2:13Most businesses have an overwhelming amount of data. It's typically scattered across the business in different tools with different teams. But because it's scattered, no one can use it. That is where HubSpot come in. HubSpot connects it all. Every interaction, every support ticket, every conversation. And they connect it into one platform that every team can work from. Because when you know more, you grow more. Check out HubSpot.com, the agentic customer platform for growing businesses. Hello and welcome. You are listening to Nudge with me, Phil Agnew, and I'm delighted to be joined again by the award-winning professor and acclaimed author, Leidy Colts.

2:54My official job is as a professor in this Department of Engineering and Society at the University of Virginia. While teaching at Virginia, Leidy wrote Subtract. The book presents a simple premise. Humans have a tendency to add rather than take away. He first noticed this with his son building Lego bridges, and Leidy then studied this Lego scenario, but he didn't stop there. He tested the same, human desire to subtract with cooking. We were doing it for ingredients in soup and asking people to make this better and yeah people definitely added. Specifically they asked 90 participants to improve a five ingredient soup.

3:3288 of those 90 participants added ingredients, only two chose to remove ingredients. To improve food we assume that more is better. There's an episode of The Bear which is a cooking show in the U.S. that people will send me clips of because there's a comment where the head chef comes around and the new chef is putting things in and the head chef gets really mad at them about adding too many ingredients and then puts a sticky note that says, subtract. What the fuck is this shit? It's way too many components. Basically made in non-chefs. You want to add another fucking sauce? Anybody got any more sauce we can add to this?

4:14We already have a dish with dill in it. You knew that, right? Yes, chef. I never repeat ingredients. We won't. So, yes, it happens in cooking. So we have this tendency to add. And yet, if you're trying to persuade or convince, adding is often the worst thing you can do. We have this idea, we have this assumption that those who specialise are higher quality. That's a previous guest on Nudge. He detailed how subtraction can often improve your marketing. He argues not to generalise and do many, many things, but instead to specialise and just do some things very well. My name's Richard Shorten and I specialise in applying behavioural science to marketing.

4:52Richard told me in a previous episode of Nudge how one of the world's fastest growing fast food brands succeeded because they took on Lydie's advice and subtracted from their offering. And there's this fascinating story about this guy called Jerry Murrell. he gives his sons an offer i'll either pay for you to go to college or i'll give you some cash to set up a business and they decide that they're gonna set up a business and forego college moral decides this is going to be the the kind of key focus of his brand he sets up his restaurant with his four sons so straightforwardly enough he calls it five guys and he just offers a very very short menu it's basically burgers and fries he doesn't have to begin with you know yogurts and salads and chicken he specializes in one area now from a kind of economic or logistical point of view there are benefits to doing that but what's really interesting is there is also a psychological benefit now let's say there's an alternate universe where there's five guys and there's six guys and they're competitors and five guys do brilliant burgers and nine out of ten and six guys do brilliant burgers and they score nine out of ten in terms of taste well if six guys offer pizza and chicken and chinese even if the physical quality of their offering is just as amazing as five guys people will not perceive it that way we have this idea we have this assumption that those who specialize are higher quality richard has evidence to prove this specifically a study on the gold dilution effect now that's not speculation you mentioned this idea of the gold dilution effect so that's a study back from 2007 by uh zhang and fishback the university of chicago and they did this beautifully simple study they recruit a group of people and then they split them into two subgroups and half the people hear about the benefits of tomatoes so you eat tomatoes and you have a reduced cancer risk.

6:58And those people are then asked, how good is tomato consumption at reducing cancer? They get their answer. They then get a new group, the second subgroup. They give them the same paragraph about cancer prevention. But then at the end, they add on a bit about tomatoes being good for stopping the degeneration of the eye. So the first group is told of one benefit of eating tomatoes. and the second group is told about two benefits you'll get if you eat tomatoes. That second group are then asked about how good are tomatoes at preventing cancer and even though they have exactly the same information regarding cancer, they score it about 12-13 % lower.

7:42This is totally irrational. People rated eating tomatoes as 12 % more effective at preventing cancer when this was given as the only benefit compared to it being listed alongside with another benefit. It's not logical, but we are more confident when just one advantage is presented. To Zhang and Fishback, this suggested that conveying one clear benefit is simply just more persuasive. Adding multiple benefits seems to dilute credibility. So the point here is if you add on extra reasons about why a vegetable is super healthy or a burger joint is really tasty, See, if you give people multiple reasons, rather than those additional reasons adding to the appeal or the believability of the offering, they actually reduce it.

8:32Because people have a rule of thumb that we can't be all things to all people, that a jack of all trades is a master of none. And once we have this rule in our head, we apply it even in situations where it's probably not appropriate. Subtracting can make our offer, our service and our product appear to be better quality. And yet so few people and brands do it. In fact, it's so uncommon that subtraction can really give you a competitive advantage. The biggest benefit of this is that just in the marketplace of ideas, right, if people are systematically overlooking a whole class of options, if you can think of that class of options, you're going to be exploiting this inefficiency that less people are thinking of subtracting to make this thing better.

9:16and if you can be the first one that does it then you have a huge advantage zhang and fishback covered more of that advantage in their study in follow-up experiments participants saw messages promoting cardio exercise running for example half were told cardio exercise helps protect you from heart disease the other half were told not only does cardio exercise protect you from heart disease but it also helps maintain healthy bones the 97 participants on average thought that cardio exercise was less effective, less effective, when they heard about the two goals, heart disease and healthy bones. Subtracting makes cardio seem better for you.

9:55But most brands ignore this. I went to Nike's website and looked at the blog they had written about why running is good for you and they list seven reasons. Adidas, ASICs, they all do the same. But after the break, Leidy explains how Nike could use subtraction to become more competitive. The Ross Simmons Show is brought to you by the HubSpot Podcast Network, the audio destination for business professionals. I've been following Ross for a while. His podcast is great. And an episode I'd highly recommend is called Mastering Time, Prioritization Over Productivity. He gives some really well thought out tips on how to prioritize your time, including something I care a lot about, which is how a small percentage of your efforts can drive the majority of your results.

10:39So go and listen to The Ross Simmons show wherever you get your podcasts. Late payments are one of the most frustrating parts of running a small business. Chasing invoices can take time and without the right support it's easy to let invoices slide. The Federation of Small Businesses have recovered over six million pounds for small businesses and they give you free template letters, step-by-step guidance and specialist support to get your cash flow back on track. It's one of the reasons I joined in the first place and honestly it's one of the benefits I probably use the most. Visit get.fsb.org.uk forward slash nudge or click the link in the show notes and use code nudge to get 10 % off your membership.

11:20Hello, welcome back. You're listening to Nudge with me, Phil Agnew. So far, Lydie Colts has covered how humans have a natural bias for addition. We like to add rather than remove. However, we've also heard from Richard Shotton, who shared how addition can dilute our offering. If we want to persuade, we should say less rather than more. Because of this, Leidy shared that merely subtracting from your ideas can give you a competitive advantage. And Leidy says this is even more important in a world where many are using AI. People have replicated our subtraction studies with AI and the AI does the exact same thing as humans.

11:56So AI has this additive bias and and that can be kind of like a multiplicative effect right where it's like you've got the the tool itself has this additive bias and then it's multiplied by the human's additive bias and you are getting even more of this problem say you're writing an email designed at persuading someone perhaps you're writing an email persuading someone to buy your product or someone to join your company or someone to come to your event. Naturally, you will feel the tendency to write more, to say more. If you use AI, it will attempt to do the same, to add more and more and more.

12:33And yet study after study shows that writing more is less effective. A few years back, I spoke to the Harvard professor Todd Rogers about this very topic. He's run one of these studies which showcases how adding more isn't best. He's proved that adding words to your email will not make that email more persuasive. Here's Todd. Sure. So we scraped 7 ,000 email addresses of elected school board members in the United States. And we were going to email them asking them to fill out a survey about important decisions they were making during the pandemic. And the actual first draft that we wrote was, I'm a professor.

13:14I'd like to ask you some questions. I know what you do is important. I know you're very busy. I know that you're serving lots of others. Thank you for everything you're doing. It's a very hard job you have. You're balancing competing interests. And like maybe six or seven sentences of just gratitude and appreciation and recognition. And then it ends by, please click this link to fill out our survey. The other condition, which was just a suggestion someone had during our development of this message. They're like, well, what if we just said, I'm a professor. I'd like to ask you some questions. You're doing important work.

13:47Will you please fill out the survey. So just reduce the words by two thirds. Before running the experiment, we actually have people predict which of these two do they think will be more effective. And people read both and almost everybody, like literally like 93 % of people reading both are like, oh, obviously the longer one that is more deferential and expresses more gratitude will be more effective. So we run the experiment more than twice as effective is the one that is much shorter. Deleting all the extra content made people more than twice as likely to respond and complete our survey, despite almost everybody thinking the opposite.

14:27One of Todd's emails had 127 words. The other had just 49 words. Despite the majority of people thinking the wordier email would perform better, Todd found the concise email was far more effective. It yielded nearly twice as many survey responses as the wordy email. That's a 4.8 response rate compared to just 2.7%. I mean, the most assigned book in the US on college syllabi is Strunk and White's Elements of Style. And like one of the core pieces of advice in that is omit needless words, right? I mean, we've all been told this. It's so hard, so hard to do. Often saying less is more. and yet like Lidy says it is very hard to do especially when we're stressed and have limited time to think yeah we gave participants in our studies one of the subtracting tasks was like random grids on a computer screen and you had to make them symmetrical from left to right and top to bottom and one of the ways to do it was the the right way to do it was to subtract blocks to make the pattern symmetrical what most people would do was add the blocks and then we there was a version of that study where while they were trying to solve the problem they would also have like a scroll of numbers going across the bottom of the screen.

15:40And every time a five went by, they had to press an F on there. So it's like you're texting and driving, basically, you're mentally distracted. And when people were mentally distracted, they were even more likely to rely on the additive solution. So again, that was for our research, it was to show that, okay, this seems like it's like a heuristic. But for the rest of life, it shows that like, Like when you're overwhelmed, you're even less likely to look for this type of solution. When you're stressed and overwhelmed, you are less likely to subtract. But as Lydie, Richard and Todd have each shared, subtracting tends to make the thing you're working on better.

16:19It's really you're just opening yourself to a whole other world of opportunities, right? This whole class of solutions that you otherwise may not think of. And then the benefits, you know, it ties into having less clutter in your physical world, having less clutter in your mind and being able to focus on things that really matter, having more time in your schedule. Like those are some of the kind of the general benefits of subtracting. But I think that the overarching one is just a whole set of solutions that you may not have otherwise considered no matter what the problem is. Subtraction. Most of us don't do it.

16:59When presented with the Lego bridge, only 12 % removed bricks. And only two participants removed ingredients from that soup recipe. Yet subtracting can often make things better. It made Five Guys more popular, it can make cardio seem more effective, tomatoes are better health food, and makes a newsletter more likely to generate donations. If there is one takeaway from today's episode of Nudge, it is this. In life, less is often more.

17:28Well, thank you so much for listening to today's episode of Nudge, folks. And thank you again for the brilliant lady for joining me on today's show. If you've liked today's episode, you will love this book, Subtract. It is critically acclaimed. I think it's award-winning. It's well worth to read. It's easy to read and still very relevant despite being written in 2021. So if you want to read that, go and pick up a copy. There's a link to it in the show notes. Before ending today's show, I want to say another thank you to the Federation of Small businesses. They have sponsored today's episode and as I mentioned in the advert I did in the middle of the show, I'm a member of the FSB and I'm a member and I signed up with my own money before they sponsored the show.

18:05So I'm really happy to have them as a sponsor because I think they're a really important asset for small businesses. I signed up to them because I run a small business that really benefits from their support. As a member I get stuff like members only discounts which have saved me hundreds of pounds on my subscription products. I'm in a community of 500 ,000 other businesses so I can get really good advice but also really good training as well from everything to making tax digital to really marketing advice as well but more importantly I get legal advice this is really important if I'm ever in legal trouble they're able to cover my legal fees I get a hundred thousand pounds worth of cover for things like tax investigation protection and I even get help with recovering debt from clients who haven't paid their invoices.

18:48As I have no employees, I pay just£195 per year for this subscription and I have made that back already in just the discounts alone. But if I ever have any problems, legal problems or problems like that, it'll be worth 10 times, even 100 times more than that. So thank you again to the FSB for supporting today's show. As a reminder, they've kindly agreed to give out a 10 % discount to Nudge listeners. They don't really do discount codes. so this is a genuinely good deal to get that click the link in the show notes and use the code nudge at checkout so please do go and become a member of the fsp today if you run your own small business thanks again i'll be back on nudge next monday for another episode thank you so much for listening cheers

From the publisher

Imagine you’re a chef. 

You are shown the recipe for a soup. It has five ingredients. 

You’re told to improve the recipe. 

What do you do? 

96% of people reveal a bias when answering this question. And that bias makes marketing less effective, communication less engaging and products less appealing. 

Find out why in today’s episode of Nudge with the award-winning professor Leidy Klotz. 

Warning: this episode contains explicit language. 

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Become an FSB member: https://get.fsb.org.uk/nudge/

Leidy’s book, Subtract: https://amzn.to/4df4duk

Leidy’s latest book, In a Good Place: https://amzn.to/4tzjCvE 

Join 11,934 readers of the Nudge Newsletter: https://www.nudgepodcast.com/mailing-list

Unlock the Nudge Vaults: https://www.nudgepodcast.com/vaults

Connect on LinkedIn: https://www.linkedin.com/in/phill-agnew/ 

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Today’s sources: 

Adams, G. S., Converse, B. A., Hales, A. H., & Klotz, L. E. (2021). "People systematically overlook subtractive changes." Nature, 592(7853), 258–261.

Rogers, T., & Lasky-Fink, J. (2023). Writing for busy readers: Communicate more effectively in the real world. Dutton.

Zhang, Y., Fishbach, A., & Kruglanski, A. W. (2007). The dilution model: How additional goals undermine the perceived instrumentality of a shared path. Journal of Personality and Social Psychology, 92(3), 389–401

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