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DUBNER: Hey, jerk, don’t pee on the floor please.

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DUCKWORTH: I’m Angela Duckworth.

 DUBNER: I’m Stephen Dubner.

DUCKWORTH + DUBNER: And you’re listening to No Stupid Questions.

Today on the show: Can posting a sign make people change their behavior?

DUBNER: A sign that says: “Just think how proud your mother would be to know that you’re washing your hands right now.” Maybe that’s the sign we all need.

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DUCKWORTH: Stephen, we have an email from one Adam Wick of Pittsburgh, Pennsylvania.

DUBNER: City of bridges. City of Steelers — and Pirates, and Penguins.

DUCKWORTH: And Carnegie Mellon University.

DUBNER: And they also— Can we just say — apropos of nothing other than the fact that Adam Wick is from Pittsburgh — Pittsburgh is a model city in transitioning from what used to be called “blue-collar work,” or “heavy industrial,” to what’s sometimes called the knowledge economy. It’s phenomenal.


DUBNER: So anyway, there should be more Pittsburghs. It’s also just lovely.

DUCKWORTH: So, Adam Wick writes, “Does posting signs cause behavioral change?” And then he elaborates: “A colleague approached me at work, asking for help in improving the design of a sign that he was going to post in the men’s room. The sign provided instructions for how to dry your hands with only one paper towel. ‘Wash your hands, shake them into the sink at least 12 times, grab a paper towel, fold it in half one time, and use it to dry your hands.’ Although the method does work well, I’m wondering if even an amazing sign has a chance of creating behavioral change. Cheers, Adam Wick — Pittsburgh, Pennsylvania.”

DUBNER: I thought this was going to be about how to increase hand hygiene, but it sounds as if it’s more about how to dry your hands with only one paper towel, as opposed to more.

DUCKWORTH: It’s more about conserving paper towels than about spreading germs.

DUBNER: And there’s a whole debate about whether paper towels in a bathroom are better than electric dryers in terms of energy consumption, and so on. I will say — years, and years, and years ago — I remember writing about how most signs that encourage people to wash their hands are put in the wrong place, which is over the sink, which is where the people—

DUCKWORTH: They’re already there. You’re preaching to the converted.

DUBNER: Right. Rule No. 1 of sign posting is: They need to be in the place where the offenders will see them, as opposed to the cooperators. But I like Adam’s question, because I feel like this is at the sweet spot of what you do and what I do. He’s asking: Do signs — which are interpreted in our brains and bodies — actually change behavior? If they do work, when do they work, and why? If you think about it, you could imagine a variety of issues with signs. Maybe people ignore a sign, or somehow it just doesn’t make an impression. Maybe it works, but only on a few of the people. Or maybe it works even for many people, but then it wears off, the novelty goes away. And you can even imagine cases in which signs backfire — where they, perhaps, encourage the behavior you’re trying to stop or even decrease the behavior you’re trying to encourage. So, I want to talk for a moment about what are called D.M.S.s — Dynamic Message Signs — on highways. Angela, I’m sure you’ve been driving or driven around enough to see these increasingly, yes?

DUCKWORTH: Yes. The ones that say, “Your speed is 36,” or however fast you’re driving.

DUBNER: Yeah. They can tell you how fast you’re going, or they can include all different sorts of warning messages, cautions, things like that.

DUCKWORTH: Like fortune-cookie messages, but all about safe driving.

DUBNER: What’s your sense — just as an individual human — how that sign might work to change your behavior?

DUCKWORTH: I guess it might work in part because it’s new information. So, it counters habituation. And then, I guess, if you are kind of oblivious to how quickly you’re going — which I think can happen. When you are going at a constant velocity, but it’s not changing, we don’t have a feeling of going fast. We can only feel speeding up and slowing down. So, maybe it draws your attention to something you wouldn’t otherwise notice. So, all of those things, Stephen, make me feel quite optimistic about the effect of those dynamic signs.

DUBNER: Well, there is research from the journal Transportation Research Record published in 2021. The paper is called, “Does Displaying Safety Messages on Dynamic Message Signs Have Measurable Impacts on Crash Risk?” They write, “Safety message data were collected from a total of 202 D.M.S.” — or Dynamic Message Signs — “on freeways across the state of Michigan between 2014 and 2018. These data were integrated with traffic volume, roadway geometry” — meaning you’re controlling for difficult and easy passages of highway, let’s say — “and crash data for segments that were located downstream of each D.M.S. The results did not show any significant difference with respect to total crashes.”


DUBNER: So, that’s bad news. “Marginal declines in nighttime crashes were observed at locations with more frequent messages related to impaired driving”— like, “Hey, if you’re drunk, get out and walk.” Although drunk walking, we actually argued in SuperFreakonomics, is more dangerous per mile than drunk driving, but that’s a different story.

DUCKWORTH: Maybe for the person who’s drunk, but maybe not for other people.

DUBNER: Exactly. It’s hard to kill someone else when you’re walking drunk. But then, they write, “Finally, speeding-related crashes were significantly less frequent near D.M.S. — these signs that showed higher numbers of messages related to speeding or tailgating.” So, maybe not hugely positive findings, but that’s positive, which might lead one to conclude that highway signage works, at least to some degree. Would you accept that as a shorthand?

DUCKWORTH: I will accept that. I mean, I was at a fundraiser for my husband, Jason — yet another of his philanthropic-slash-civic causes. He’s a big advocate of pedestrian safety and cyclist safety. Anyway, we recently had an event to raise money for this PAC aimed at improving the safety of cyclists and pedestrians in the state of Pennsylvania. The invited guest was Erick Guerra, who’s a professor at my university, University of Pennsylvania. And he essentially specializes in the interface of the built environment and transportation — like highways, crosswalks, signage —and then humans. So: drivers, pedestrians, cyclists. And I asked him, “Can you just summarize the literature for me? What works?” One of the things he said is that one of the best ways to do it is not necessarily signs per se, but actually the roadways themselves. So, you can put up all the signs you want, but if it’s, like, a huge straight shot, people are going to go really fast. If you have a really windy, small, narrow road, then people are going to go slower. So, I think a lot of the innovation here is not signs per se, but the structure of where we’re driving itself.

DUBNER: But that said, if you’re working with a built environment that’s already built, which of course many safety experts are, you think, “What can I add?” And if you add signs, this paper from Transportation Research Record seems to show there’s some gain to that, but — you knew there was a “but” coming, did you not?

DUCKWORTH: There’s always a “but.”

DUBNER: There’s an even more recent paper published in Science by Jonathan Hall and Joshua Madsen. Jonathan Hall is an economist at University of Toronto. The other, Madsen, is a professor of accounting — University of Minnesota. And they write the following, “Although behavioral interventions are designed to seize attention, little consideration has been given to the costs of doing so.” In other words: That sign up there — we want it to produce a benefit. Might it cost something too? They write, “We estimated these costs in the context of a safety campaign, that to encourage safe driving, displays traffic fatality counts on highway dynamic message signs for one week each month.”

DUCKWORTH: That was such antiseptic language. “Fatality counts.” Like: the number of people who have died.

DUBNER: Yeah. Like, “eight people died on this highway in the last month,” let’s say. And again, there seems to be an experimental instrument here, which is: the signs are only going up for one week each month, which means that you can measure the week they’re up and when they’re down.

DUCKWORTH: Very clever. Ugh, you know, that is possibly going to have the effect of distracting me, just because it’s so kind of, like, “Oh my God.” And by the way, since it didn’t tell me how fast I was going, it distracts me and doesn’t necessarily get me to slow down, either.

DUBNER: Right. It doesn’t put you in with the group of “speeders” or “not-speeders.” It puts you in with the group of “alive” versus “dead.” And all of a sudden, you just saw the number of dead.

DUCKWORTH: I’m going to predict that it is either neutral because the costs equal the benefits, or, I don’t know, possibly bad? I’m not sure.

DUBNER: I’ll read on here from the paper by Hall and Madsen: “We found that crashes increase statewide during campaign weeks” — that means the weeks when the signs are running — “which is inconsistent with any benefits. Contrary to policymakers’ expectations,” they write, “we found that displaying fatality messages increases the number of traffic crashes.” So, they conclude: “Back-of-the-envelope calculations suggest that this campaign” — again, a campaign that’s designed to save lives — “causes an additional 2,600 crashes and 16 fatalities per year in Texas alone, with the social cost of $377 million each year.” How nuts is that? Or maybe, if you’re Angela Duckworth and you know the way the human mind works, maybe it’s not so nuts.

DUCKWORTH: Well, look, I’m not going to pretend that I could have guessed that right off the bat. I could see it going either way. But I’m curious whether these scientists had any explanation for why it is.

DUBNER: They propose a number of hypotheses, and the one that they land on: “One proposed explanation,” they write, “for the surprising finding is that these ‘in-your-face’ or ‘sobering,’ negatively-framed messages seize too much attention. That is, they are too salient, interfering with drivers’ ability to respond to changes in traffic conditions.” So, Angela, I am really glad that this question about how to fold a paper towel to dry your hands has brought us to this question, which I consider a little bit higher-stakes. Because — it’s not just with traffic safety; it’s with a lot of things — I keep coming across this word, “salience,” in psychology, but also in econ papers, too, which is this argument that once you become aware of something — once something becomes fully or largely salient — it really affects our behaviors in ways that you might not anticipate. Can you just talk about salience from your perspective for a minute?

DUCKWORTH: There’s an aperture, if you will, that can be fully dilated — and you’re completely aware of something — or completely closed —where it’s happening, but you just didn’t notice. Say there’s a sign by the side of the highway that you didn’t look at. For you, it didn’t exist. So, salience is the extent to which something enters your field of view — your awareness. And it can be anywhere from zero to 100 percent. When we’re in the flow state, and we’re completely engaged in activity, all of our attention is going to what we’re doing. And the opposite of that would be, like, complete neglect.

DUBNER: But in a more complicated interaction — let’s say you’re driving down the highway, you see the sign — what these scholars are arguing is that salience increases, essentially, bad outcomes of traffic crashes. How could that be?

DUCKWORTH: Because attention is going to the sign. So: I look up, and I’m probably not only looking away from what’s in front of me. Perhaps, for that moment — and this is complete speculation — the emotion of that, like, you know, “Two people died on this highway in the last year.” I maybe have memories or thoughts triggered of people I know who died. I mean, who knows what’s going on, but basically, I want to make the point that, when we talk about attention, it’s not only “attention to this object versus that object” — the sign versus the odometer, or the steering wheel versus the person next to me — but there’s also a kind of internal spotlight: Is my attention going to one thought, or the other thought? When someone’s driving, you really want their attention externally to be on the cars around them, and then internally to be on driving.

DUBNER: I guess that’s not that’s not the scenario I was— I was picturing a scenario whereby it’s not that I’m distracted in the moment by the sign and get in a crash within the next half mile. It’s that I read that, and I think about, “Oh my goodness, this thing I’m doing is dangerous.” Theoretically, it could make me more careful, but theoretically, it could make me tense up. We know that most of us don’t respond well to pressure — if you look at test-taking, and sports, and things like that. It takes a lot of practice and experience to deal well with pressure. That was the mechanism that I was imagining was the response to salience. But I don’t know. We’re both speculating here.

DUCKWORTH: I don’t think this study, just from what they did, would be able to say that one account is more right than the other. By the way, they’re both possible, but they both do start with attention going to that sign.

DUBNER: It does remind me of another story. I bet you know this story, because this is a famous story, and it was popularized by someone that you are a great admirer of. Do you know this story of the petrified national forest in Arizona and what happened there?

DUCKWORTH: I do know the story. This is Bob Cialdini, yeah?

DUBNER: This is Bob Cialdini. And this was some time ago. And I don’t know the story that well, but from what I recall, it goes something like this: There’s the Petrified Forest National Park in Arizona, where Cialdini lives. The problem is that people would go in and steal pieces of petrified wood and crystals from the forest floor. That’s plainly not good for the integrity of the forest.

DUCKWORTH: They would just put it in their pocket to take home and put on a shelf.

DUBNER: I think all of us can imagine that sentiment. It’s just like, “Oh my gosh, it’s so cute. It’s one little thing.”

DUCKWORTH: And there’s so much of it!

DUBNER: It’s a whole forest! And so, as he described it, there’s a sign as you come in the park that says, “Because so many people are stealing wood at the rate of nearly a ton a month, this is undermining the integrity of the forest.” So, Cialdini had a graduate student working with him. The student and his fiancée went to the forest and saw the sign. And the student said that, before he even finished reading the sign, he heard his fiancée say to him, “Oh, we better get ours now, before it all disappears.” So, he was wondering, like, what on earth could possibly produce that sort of result? Cialdini, being a scientist, turned this into an experiment. And they ended up putting up a sign, or number of signs, in front of different pathways running through the forest. And they actually, as he put it, “salted” those pathways with pieces of petrified wood. And then they looked to measure the effect of the sign on stealing the wood. In other words, if we have a sign that says, “Please don’t steal the wood, too many people are stealing the wood, da-da-da,” what happens?

DUCKWORTH: Compared to no sign, right?

DUBNER: Compared to no sign. And having the sign tripled the rate of theft. Is that salience? Is that what that is?

DUCKWORTH: It’s salience, but signs always convey something in addition to that, which is some kind of message. And in the case of the petrified forest, it is signaling to you: “Everybody steals wood from the petrified forest. What’s wrong with you? Why haven’t you stolen your piece yet?” It’s conveying a “social norm,” in the terminology that Cialdini might use. I think you also want to think about what that sign is doing then in this bathroom that Adam talks about. The sign provides instructions for how to dry your hands with only one paper towel, et cetera. I think, in some ways, what this sign might be doing is that, if it just says, like, “Don’t forget to wash your hands,” it’s communicating to you, “You probably would’ve forgotten. We have to scold people. We have to put up a sign in the bathroom because nobody’s washing their hands.” It’s not communicating that. It’s communicating to you this, kind of, “pro tip” — this hack so that you can only use one paper towel. That, to me, is really important, because, as a practical matter, you want signs that are not only going to bring things to the top of mind, to make things salient, but also carry some information that makes people more inclined — as opposed to less inclined — to do the wanted behavior.

DUBNER: So, Angie, I do think it’d be really interesting to hear from listeners about signs that have worked — or failed to work on them, maybe? What do you think?

DUCKWORTH: I think that would be fantastic. I want to hear sign stories.

DUBNER: Send us your sign stories. Make a voice memo. Just make a recording with your phone. Do it in a quiet place. Speak nice and clearly. Include your name, and email it to us at, and maybe we can share it in a future episode.

Still to come on No Stupid Questions: What happens when even the most intelligent, informed people refuse to follow the signs?

DUBNER: They were going to jump out from their hiding spot, scowl at them, and then take their name and publicly post it to shame them.

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Now, back to Stephen and Angela’s conversation about how signage affects human behavior.

DUBNER: When we see a sign, I think one thing we don’t necessarily think hard about, but we feel, is: Who’s the author of that sign? Who is the authority figure who’s posting it or asking that it be posted? And: Who is the intended beneficiary of the behavior? It could be you; it could be other people. And also: Is the message of the sign kind of dictatorial, or is it more collaborative?

DUCKWORTH: Is it complimentary? Is it insulting?

DUBNER: One of the most famous examples from the book Nudge by Thaler and Sunstein was about putting an image of a fly — a housefly — on a urinal in the airport — I think it was the airport in Amsterdam. Thaler and Sunstein didn’t come up with this. They just thought it was a great example of nudge framework, which is: If you’re a guy standing there, ready to pee, rather than peeing on the wall or on the floor — which men sometimes do — if there’s a fly, “Oh, it’s a game. I have a target. I’m going to pee on the fly.” And so, that’s a sign, but it does a couple other things, too. It does gamify it. It makes it fun. And it makes you a participant in the behavior as opposed to a sign that says, “Hey, jerk, don’t pee on the floor, please.”

DUCKWORTH: You know, I read that little anecdote, and I’m not an expert on men’s urinals.

DUBNER: “Not having a penis, I dismissed it as a useless anecdote.”

DUCKWORTH: Has it, kind of, taken off? Are there little cute targets in men’s urinals all over the world because of this trick? A lot of people read that book, Nudge.

DUBNER: I’ve definitely seen flies or bullseyes in more urinals than there used to be, but I would not say it’s universal.

DUCKWORTH: I think there should be more of that. And I do think that is not only a reminder, but it’s communicating something which is certainly not insulting or dictatorial. I mean, I have a memory of this speed sign in a part of a suburb of Philadelphia where I used to live, called Narberth. And there was this long cul-de-sac — a street called Narbrook Park. And in the park, there was a speed limit sign that said seven-and-a-half miles.


DUCKWORTH: And I thought it was incredibly clever. I can’t say whether it worked or not. There wasn’t a control group. But I think what that sign is communicating is, “Hey, we want to remind you to slow down.” The seven-and-a-half mile thing is a little cheeky, but there’s nothing insulting about it. You want signs that both work on your attention, but don’t backfire by making you feel suspicious or antagonistic in any way.

DUBNER: It’s so interesting. You know, I really do empathize — whether it’s with the company that Adam is talking about, or someone running a highway department, someone trying to create safety anywhere — it’s hard to predict what will work, whether it’s a sign, or a kind of encouragement. Even incentives. Going back to hand washing, which is where this conversation began, I don’t know if I’ve ever told you this story about how one of the world’s best hospitals found that their hand-hygiene rate among doctors was only about 60 percent. This was Cedars-Sinai Medical Center in Los Angeles. Have I ever told you this story, Angela?

DUCKWORTH: I don’t think so.

DUBNER: So, the story of hand-hygiene compliance in hospitals — it’s a big deal, because of all the things that cause problems, especially bacterial infection, poor hand hygiene is not only a big contributor, but it’s also an easy win. If you can get people to wash their hands — or disinfect their hands — routinely, it is simple, cheap, and effective. And yet, as I mentioned, at Cedars-Sinai, which is a world-class hospital, they found that the hand-hygiene rate among their physicians was about 60 percent. And they found this not by asking in a survey, which will give you higher numbers, but by deputizing nurses, essentially, to spy on doctors. And that’s how you create the baseline figure from which you try to measure. And so, when the leadership at the hospital learned that their rate was only about 60 percent, they were mortified. And they did what we, especially, in the U.S. and other places do when you take a problem really seriously, they decided to form a committee. It was called the Cedars-Sinai Medical Center Chief of Staff Hand Hygiene Advisory Committee.

DUCKWORTH: That rolls off the tongue.

DUBNER: So, they got together, and these were, I think, maybe 15 or 20 of the top officials in the hospital, many of whom were medical doctors themselves. They decided: What we’re going to do to solve this problem is we are going to communicate to our physicians here that we expect and appreciate 100 percent hand-hygiene compliance. And so, they wrote a memo, because that’s what committees do.

DUCKWORTH: Especially ones with long acronyms.

DUBNER: And they distributed the memo. And would you think that the memo increased hand-hygiene compliance, or no?

DUCKWORTH: I would imagine it might have decreased hand-hygiene compliance.

DUBNER: Well, it didn’t decrease, thankfully, but it didn’t increase it, either. So, then they had a totally different idea. They thought, “What if we take our message to the wards where the doctors are actually seeing the patients, and try to change the messaging there?” So, they formed the Posse Patrol Program Subcommittee of the Cedars-Sinai Medical Center Chief of Staff Hand Hygiene Advisory Committee. And this would be composed of two or three members of the big committee. They would go into a patient’s room and literally hide, and wait for a doctor to come in and either wash — or fail to wash — his or her hands. And their initial plan was, as an incentive, they were going to use not a carrot, but a stick.


DUBNER: If they caught someone not washing, they were going to jump out from their hiding spot, and I guess, I don’t know, scowl at them, and then take their name and publicly post it to shame them.

DUCKWORTH: Very “Singapore.”

DUBNER: Then they thought, “You know what? What if instead of a stick, we use a carrot?” And they came up with a plan. They still hid behind a wall, or curtain, whatever, but if they heard a doctor successfully wash his or her hands, they would jump out, they would applaud, and give the doctor a $10 Starbucks card as a reward for successfully washing hands. Now, what would you guess would be the outcome of that incentive?

DUCKWORTH: I don’t know how sustainable this is, but I would imagine that that would work better.

DUBNER: Right. It worked well in that people loved it. Some doctors would even game the system. When they would hear the Posse Patrol Program was on their floor, they’d run up there and wash their hands — try to get cards. But it did not raise the rate overall. I mean, you can imagine a number of reasons why. Maybe if I got the Starbucks card in room, you know, 804, and I go into room 809, I know the Posse is not there, maybe I skip it there. So, that made people feel good, but it didn’t work. What finally worked was: Back at a meeting of the whole big committee, someone spoke up who hadn’t spoken up before. It was a staff epidemiologist. And she said, “I have an idea. It’s not actually a solution to the problem, but it’s an idea for, maybe, helping us think about the problem a little bit differently.” And she pulled out a bag with 20 Petri dishes, the kind of thing you take a sample from and culture it in the lab.

DUCKWORTH: Grow bacteria.

DUBNER: And she said, “Here we are, the senior leadership of the hospital, telling everyone else how they’re failing to wash their hands. What about us? Do we have these bacteria on our hands?” So, she asked everyone to lay their palms in these Petri dishes, and she wrapped them up, and she sent them to the lab. And it turns out that the majority of those palm prints were teeming with the bacteria that other doctors were failing to get rid of. And that was a sobering moment for them. And they felt, “Not only are we not solving the problem, but we’re contributing to it.” And that’s when the chief of staff came up with what was ultimately the winning solution, which was: He said, “What if we take a photograph of one of these Petri dishes with these really scary-looking bacteria on it and let it be known that it belonged to one of us, the leadership? And what if we make it the screensaver on every computer in the hospital?” And they did. And that sign worked.

DUCKWORTH: Did it really? I have to say, I’m surprised.

DUBNER: I was surprised, too! I think this goes to the fact how hard it is to predict human behavior, whether it’s in response to a sign, or any other kind of incentive.

DUCKWORTH: I’m also going to register some skepticism that it worked in the long run.

DUBNER: Why would you say that?

DUCKWORTH: It’s not just Cedars-Sinai. I have been working on this dataset with Colin Camerer and Katy Milkman. Katy is the person among us who originally acquired the dataset on hand-washing in a hospital system — a set of hospitals — and the lead author is Anastasia Buyalskaya. We’re looking at hand hygiene. And we have better data than looking from behind curtains in hospital rooms, because these physicians and nurses wore transponders, and when you approach the sink, you can reliably know whether or not the person has washed their hands. And I believe, in our dataset, it is fewer than 50 percent. So, it’s much lower than what you’re seeing in Cedars-Sinai. And I’ll just say that it’s just very hard to change this behavior. I would guess that that screensaver might have an effect for a little while, but what we’re seeing in this data is that it takes an extremely long time to form a hand-washing habit. And this kind of gets back to that observation that maybe better than street signs is changing the road itself. Like, when you make a speed bump on a road, or you make it narrow, or you make rumble strips on the side, you make certain kinds of driving immediately more pleasurable than others — like, driving slowly, driving carefully. I think signs have some utility, but it’s limited.

DUBNER: And, to that point, in terms of the Cedars-Sinai story, the sign worked for quite a while. In fact, it worked so well that other hospitals began to write Cedars-Sinai and say, “Hey, could you send us that image of your doctor’s bacterial hands?” But if I recall correctly, it did work for a while, and then it diminished — exactly like you said, because habits are hard to form. But when you talk about traffic design, or the built environment, having so much more power than, let’s say, road signs, I think, in the hand-hygiene space, it’s exactly the same thing. The gains that are being made are much more when you look at hospitals that use antimicrobial surfaces, for instance. And then there are some easy gains. You know, if you think about a physician’s necktie — if they’re the kind of person that wears a necktie — can act over the course of days, weeks, and months as a sort of giant germ swab, just kind of gathering stuff. And men — I don’t know if you know this about men, but we have a very concrete dry-cleaning calculus: How many times you can wear a particular item of clothing before it has to be cleaned.

DUCKWORTH: Oh. Does anybody ever clean their ties?

DUBNER: Yeah. The tie is at the bottom of the list.

DUCKWORTH: That’s so interesting. I hadn’t thought about that.

DUBNER: The British Medical Association, I believe, was the institution that decided to ban the wearing of neckties in hospitals. Because they thought, “Listen, the necktie is this ancient symbol that you’re an important person. Well, you’re a doctor. We know. You don’t have to remind us, but if your necktie cannot serve as a giant germ swab in this hospital and save one life, we think that’s probably more important.” So, that’s another example where, let’s call it the built environment, or the environment generally — as opposed to relying on signs that might or might not change behavior, and even if they do, might only change it for a little bit — sounds like very much the way to go.

DUCKWORTH: So, in response to Adam Wick — Does posting signs cause behavioral change? — I think your answer would be that maybe, sometimes, a little bit, but it often backfires. But changing the structure is a really good idea for causing behavioral change. Do I have that right?

DUBNER: You have it right according to me. The problem is that built environments are built. And we’re often left with either really expensive changes or tweaks on the margin, which is what signs are. I mean, I could imagine, however, that someone as clever as you could work with your also-clever colleagues, like Colin Camerer and Katy Milkman, to come up with a science of sign-making that is better. Because, look: As you like to say, “both/and.” Let’s use all the tools in the arsenal. And so, sometimes you’re going to have an environment that you can’t rebuild, and that signs can be at least somewhat useful. I mean, if you think about what we were discussing earlier: Who is the author of the sign? Who is the authority behind it? Who are you trying to benefit? You know, maybe a sign that says, over the sink, “Just think how proud your mother would be to know that you’re washing your hands right now.” Maybe that’s the sign we all need.

DUCKWORTH: I don’t know if it’s the sign we’ll need, but how about this: I think if you could make it a game, where it tells you how many seconds the water’s been on, and you don’t want to go over 20, because you don’t want to waste water, but you don’t want it to be under 20. And then, when you wash your hands for exactly 20 seconds, a random Beyoncé lyric will play. You don’t know which one! I think that’s the kind of thing that would make it salient. It would be not dictatorial. It wouldn’t be critical or finger-wagging, but it would be, actually, bordering on structural. So, I will say that this is a great homework assignment for Colin Camerer and Katy Milkman, but we’re going to need a budget.

DUBNER: That is such an amazingly good idea, or at least amazingly appealing idea. You’ll have to see if it actually is good. So, Angela, I’m in a hurry to leave this conversation to go to the bathroom to hear my Beyoncé. So, thank you.

DUCKWORTH: Okay, good. Don’t forget to wash your hands.

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No Stupid Questions is produced by me, Rebecca Lee Douglas. And now here is a fact-check of today’s conversation.

Stephen says that he’s unsure about certain details in the story about flies etched into urinals from Richard Thaler and Cass Sunstein’s 2008 book Nudge. As Stephen suspected, the example came from Amsterdam — specifically, the men’s restrooms in Schiphol Airport. Aad Kieboom, an economist who, at the time, was the director of Schiphol’s building expansion, came up with the idea. His staff reportedly found that fly-in-urinal trials reduced spillage by a total of 80 percent. I wasn’t able to find reliable figures on the percentage of men’s restrooms that use urinal etchings today. But I did see that one can now purchase a diverse range of urinal bullseyes and targets at affordable prices from websites like Amazon and Etsy.

Later, Stephen tells the story of the Cedars-Sinai Medical Center Chief of Staff Hand Hygiene Advisory Committee, which he initially wrote about with Freakonomics co-author Steve Levitt in a 2006 article for The New York Times. He recalls that the Starbucks card incentive was well received, but didn’t actually raise hand-washing rates. This isn’t entirely correct. Compliance did in fact rise to about 80 percent from 65 perfect, but this was deemed unsatisfactory as the commission wanted at least 90 percent compliance. By comparison, the photograph of the Petri dishes led to nearly 100 percent compliance. According to Richard Riggs, the Chief Medical Officer at Cedars-Sinai, the hospital no longer uses the image, but he does stress that they still have, quote, “exemplary rates of compliance with hand hygiene.”

Finally, Stephen mentions a British Medical Association ban on neckties. The policy was actually instituted by the UK’s Department of Health and Social Care. The British Medical Association is the trade union for doctors; many of its members were affected by the ban. NHS dress code currently indicates that employees should not only avoid neckties, but also lanyards, necklaces, hoop earrings, and rings. Bowties are considered safe.

That’s it for the fact-check.

Before we wrap today’s show, let’s hear your thoughts on last week’s episode on the midlife crisis. We asked listeners to send us voice memos sharing their own stories and experiences.

Ali MUDD: Hi. This is in response to the midlife crisis episode. I’d like to say I think I’m too young yet to have a midlife crisis as well, because I’m 33. But I think I did have a quarter-life crisis at 25, and I think it was entirely because of thinking if you’ve made the right decisions so far. So, I chose to be an architect, and in the U.K. that takes a minimum of seven years, and it took me 10 years. And, at 25, I was sort of more than halfway through it, I guess, and really just thinking about whether it’s what I want to do with the rest of my life. And, for me, it was. I have my own business now, and I really enjoy it. But the whole process of almost, like, acute worry and depression — of really, like, “Is this the right thing for me?” — I think that’s kind of what a midlife crisis is in my estimate. It’s kind of like an introspection on whether you’ve made the right choices up until that point and if you’re happy with what you have.

That was listener Ali Mudd. Many thanks to her and to everyone who sent us their thoughts.

Coming up next week on No Stupid Questions: What’s so satisfying about holding a grudge?

DUCKWORTH: You lied to me. You cheated on me. You tripped me. You hurt me.

That’s next week on No Stupid Questions. And remember, we’d still love to hear your thoughts and stories about signs. Just send a voice memo to with the subject line “Signs.” Make sure to record someplace quiet, and please keep your thoughts to under a minute. Maybe we’ll include them on the show!

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No Stupid Questions is part of the Freakonomics Radio Network, which also includes Freakonomics Radio, People I (Mostly) Admire, and Freakonomics, M.D. All our shows are produced by Stitcher and Renbud Radio. This episode was mixed by Eleanor Osborne. We had help this week from Jacob Clemente. Our staff also includes Neal Carruth, Gabriel Roth, Greg Rippin, Julie Kanfer, Morgan Levey, Zack Lapinski, Ryan Kelley, Jeremy Johnston, Jasmin Klinger, Emma Tyrrell, Lyric Bowditch, and Alina Kulman. We had additional research assistance from Anya Dubner. Our theme song is “And She Was” by Talking Heads — special thanks to David Byrne and Warner Chappell Music. If you’d like to listen to the show ad-free, subscribe to Stitcher Premium. You can follow us on Twitter @NSQ_Show and on Facebook @NSQShow. If you have a question for a future episode, please email it to To learn more, or to read episode transcripts, visit Thanks for listening!

DUBNER: James Carville once said that Pennsylvania is Philadelphia and Pittsburgh with Alabama in the middle.

DUCKWORTH: He’s not wrong.

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  • Anastasia Buyalskaya, professor of marketing at HEC Paris.
  • Colin Camerer, professor of behavioral economics at the California Institute of Technology.
  • Robert Cialdini, professor emeritus of psychology at Arizona State University.
  • Erick Guerra, professor in city and regional planning at University of Pennsylvania.
  • Jonathan D. Hall, professor of economics at University of Toronto.
  • Joshua M. Madsen, professor of accounting at University of Minnesota.
  • Katy Milkman, professor of operations, information, and decisions at the University of Pennsylvania.
  • Richard Thaler, professor of economics at the University of Chicago.
  • Cass Sunstein, Robert Walmsley university professor at Harvard University.



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