Search the Site

Episode Transcript

Hey there, it’s Stephen Dubner. Have you noticed that the world has gotten noisy again? The pandemic quieted things down; but on the noise front at least, things are getting back to normal. So we thought it would be a good time to replay an episode from our archive, called “Please Get Your Noise Out of My Ears.” We’ve updated facts and figures where necessary. Also: we need your help for a future episode we are working on. It’s about personal finance. If you have something to say, record a voice memo on your phone and send it to Be sure to include your name, age, where you live, and what you do — and try to record in a nice, quiet place. Here are three questions I’d like you to answer — feel free to answer any one, two, or all three. Here we go: Number one: where do you get financial advice? Number two: what’s something you wish you knew about money, or at least wish you had known sooner? And, number three: tell us about a money mistake you made, and maybe the lesson you learned. Again, use your phone to record a voice memo and send it to Thanks in advance — and now, I hope you enjoy “Please Get Your Noise Out of My Ears.”

*      *      *

Peter TYACK: Humans and animals have evolved in environments that have a lot of noise. We have noise from rain. We have noise from thunder. We have noise from other animals like birdsong or crickets chirping. But human industrial activities also have introduced a lot of noise that are quite different from the sounds that we and other animals have evolved to live with. 

Peter Tyack — T-Y-A-C-K — is a behavioral ecologist, at the University of St. Andrews, in Scotland.

TYACK: And I’ve studied the sounds of mainly marine mammals, and that’s given me an entry point to understanding how sound travels in the ocean, which is quite different from what we’re used to on land. 

Different how?

TYACK: We, as terrestrial mammals, are used to vision being the great distance sense. We can see things from very far away, much further than we can hear. But if you’ve snorkeled in the ocean, you know you can only see about 10 meters, something like that, but you can hear much further away. So, the key difference between life on land and life underwater is that for a mammal that wants to understand what’s far away, they really need to rely on sound in the ocean.

Sound in the ocean therefore exerts a lot of leverage. Sometimes this is good news. Consider a recent experiment by scientists working at the Great Barrier Reef off of Australia. When a coral reef is healthy, it’s quite noisy with the sound of marine activity, and that noise attracts more activity. But a patch of coral reef that’s dead or dying is quiet. So, the scientists went to these quiet patches and placed speakers underwater to play the sounds of a noisy reef.

It seems to have worked, attracting lots of fish, who stayed on. Here’s how the researchers put it: “Acoustic enrichment shows promise as a novel tool for the active management of degraded coral reefs.” So, there are beneficial ocean sounds and the opposite. Peter Tyack was once studying whales in the Bay of Fundy, off the Canadian coast. It was generally a good place for whales to be, with lots of appetizing food:

TYACK: But there also are shipping channels near there.

As part of his research, Tyack recorded the calls that whales make:

TYACK: But always in the background was the sound of shipping noise. 

Researchers like Tyack had never really thought much about this background noise. It was just there. But then all of a sudden it wasn’t. The change came with the 9/11 terrorist attacks.

TYACK: All of a sudden, the ships that were plying the ocean in that area stopped. 

This drop in ship traffic was only temporary. But it happened to coincide with some other whale research that was happening in the Bay of Fundy.

TYACK: Researchers from the New England Aquarium had been sampling feces from whales to look at stress hormones. It wasn’t part of a noise experiment at all. 

It was just, you know, your standard whale-feces research.

TYACK: But what they found was that if you compared the stress hormones in whales before 9/11 and after 9/11, their stress hormones actually went down after 9/11. 

I’m guessing you didn’t wake up this morning thinking you’d be hearing about whale feces and stress hormones. But noise? You probably think about noise all the time. I know I do. Especially as the pandemic has rearranged our world, our routines, our soundscapes. Think how hard it can be to control the background noise in these new settings, especially when someone else is generating the noise. If whales are stressed out by noise, how about you? Before we answer that question: let’s gather some more whale evidence. Peter Tyack told us about another type of whale:

TYACK: A very poorly known set of toothed whales called beaked whales.

When U.S. Navy ships in the Bahamas ran exercises using sonar — that’s “sound navigation and ranging,” which emits bursts of underwater sound — these beaked whales had trouble.

TYACK: Over a period of a few hours, whales would strand by ones and twos over tens of kilometers of beach. 

Tyack and his colleagues wanted to learn just how sensitive the whales were to these sounds. So, they developed tags to track the whales’ behavior and then dropped speakers in the water to play their own sonar noise, first at very low levels.

TYACK: What we found was that at quite low levels of exposure, much lower than the levels that actually cause hearing damage, the animals would stop making their echolocation clicks, then stop foraging, and they would then do a very long, slow ascent to the surface. 

This surfacing is unhealthy for the whales.

TYACK: It may cause an explosive decompression syndrome in which they get gas bubbles in their body, like a diver with the bends, that could even cause animals to die at sea. Or they may panic and strand on shore. 

Why would the whales have such a drastic reaction to such low levels of sound?

TYACK: This is something that’s seen in a lot of wildlife, that if they interpret a sound as a threat, they’ve evolved anti-predator responses. And these may cause them to show pretty strong responses at relatively low levels of sound.

The science shows that most humans are not nearly as sensitive to sound as whales. Still, you have to consider what kind of responses we are having — knowingly or unknowingly — to all the noise around us. Even if it doesn’t seem particularly “noisy.”

TYACK: We’re just used to the baseline of the ambient noise around us. So, if you grow up in New York, your baseline is the sounds of planes flying overhead and fire engines going by. And that’s something that you don’t really pay attention to.  

Most guidelines say that sounds above 85 decibels are physically harmful. But think of all the baseline sounds we barely notice. Normal breathing is around 10 decibels; a computer fan, 20. The hum of a refrigerator is around 40 decibels. A dishwasher, 75; a window air-conditioner: more than 80. Then there’s the drive-by D.J.’s, the occasional fireworks, and of course, the quintessential 21st-century sound: the one-sided cell phone call.

Today, on Freakonomics Radio, the economics of noise:

Josh DEAN: One very economics-y thing that I worry about is that noise is very susceptible to a race to the bottom. 

How people suffer from noise:

Margaret JASTREBOFF: He said, “I’m not afraid of sound. Sound is making me upset.” 

And what can be done about it:

Arline BRONZAFT: One word and that’s the word called “respect.”

*      *      *

Here’s a question to start with: what is particular about sound?

Mack HAGOOD: Sound doesn’t respect barriers very well. As many people have pointed out, there are no ear lids.

That’s Mack Hagood. He is a scholar of sound at Miami University in Ohio, and the author of a book called Hush: Media and Sonic Self-Control.

HAGOOD: Sound has always been a challenge to our sense of autonomy. 

Emphasis on the “always.”  

HAGOOD: We can look back at the famous stoic Seneca, back in ancient Rome, who wrote that if you were truly in control of your own consciousness and emotions, then you should be able to withstand any sort of sound. And yet eventually Seneca moved out of Rome to the Roman suburbs because he couldn’t stand the noise anymore.  

Noise like carpenters at work and musicians in the public square.

HAGOOD: So, I kind of picture he’s moved out by IKEA.

The philosopher Arthur Schopenhauer, writing in 19th century Germany, complained that the cracking of horse whips “paralyzes the brain … and murders thought.” I submit that if people like Schopenhauer and Seneca considered noise worthy of their attention (and disdain), we may follow suit.

HAGOOD: Absolutely. And sound has changed a lot in modernity and the world has gotten noisier. So, we have new kinds of factory noise. We have new kinds of noise from transportation — railways, automobiles, airplanes. And then we have new kinds of ways of consuming sound itself: through the radio —

Pegeen FITZGERALD: We kept you awake, but now, pleasant dreams, and be with us again tomorrow night, will you?  

HAGOOD: — through the television —   

Oprah WINFREY: I’m Oprah Winfrey, and welcome to the very first national Oprah Winfrey Show! 

And through podcasts, of course. You have chosen to put the sound of my voice in your ear. Why I cannot say. But you have!

HAGOOD: On the other hand, we are also becoming more finicky when it comes to sound.  

Some people, for instance, seek out sounds that trigger what’s called A.S.M.R., or “autonomous sensory meridian response.” That’s a tingly, relaxing feeling some people get when listening to the sound of, say, a bar of soap being carved or typing on a keyboard. Plainly, the modern menu of sound is a vast, all-you-can-eat buffet. But just as plainly, many sounds are thrust upon us, which has had significant consequences.

HAGOOD: We’ve gotten new diagnoses that have popped up that just never existed before. 

Hyperacusis, for instance, a rare but debilitating sensitivity to certain frequencies and ranges of sound. Or phonophobia, a fear of sound. And then there’s misophonia, a condition that was identified relatively recently. The name means hatred of sound, although the man who named misophonia admits the name is imperfect.

Pawel JASTREBOFF: Misophonia, God forbid, should not be translated literally as a hate to sound. 

That is Pawel Jastreboff.

Margaret JASTREBOFF: I would say like this.

And that’s his wife, Margaret Jastreboff.

M. JASTREBOFF: Misophonic reaction is negative reaction to specific sounds, or sounds in very particular situation, produced by one or two specific people or in specific situation. 

Okay, that’s a little bit helpful. So, misophonia is a negative reaction that certain people have to certain sounds in certain situations?

M. JASTREBOFF: Oh, it’s a long story.

The Jastreboffs run the Jastreboff Hearing Disorders Foundation Clinic in Maryland. Before that, they were medical-school professors at Emory University School of Medicine.

P. JASTREBOFF: Yes. Still professor emeritus, which actually gives me a great privilege of having free parking.

It was at their clinic that Margaret Jastreboff first noticed this interesting new condition. Some patients reported an extreme sensitivity to certain sounds. Typically, this would be diagnosed as phonophobia — a fear of sound. But that label was upsetting to these patients. Margaret recalls how one of them stormed out of the examination room:

M. JASTREBOFF: He screamed at me, and he said, “I’m not afraid of sound, I’m not fearful. Sound is making me upset. I cannot control my reaction.”  

The Jastreboffs found there were a range of specific sounds that upset different patients.

P. JASTREBOFF: For example, a sound of a door closing or airplane flying or sound of eating or sound of kissing, for example — interesting case. 

Why would someone have no problem with most sounds but become distraught over the sound of eating or kissing?

M. JASTREBOFF: So, we start thinking about this and we realized that it’s not only fear. It is something definitely more complex. 

One of the most common misophonia triggers is the sound of chewing. You may dislike the sound of someone chewing their food. But for someone with misophonia, the sound is excruciating. Where does this come from?

P. JASTREBOFF: What I believe, what I’m proposing, misophonia reflects subconscious connection. 

A subconscious connection with, in all likelihood, an unhappy event. Imagine you’re a little kid at Sunday dinner with your whole family and your grandfather’s dentures fall out onto the table. The feeling you had then — an icky feeling — could become subconsciously associated with the sound of anyone chewing. And it could subsequently generate an automatic, physiological reaction. To treat patients with misophonia, the Jastreboffs have drawn on a method used to treat people with tinnitus. That’s a disorder most of us think of as a “ringing in the ears.”

P. JASTREBOFF: But is not necessarily ringing. It can be any kind of a sound — can be hissing, can be sound of insects. There’s some people who are hearing Christmas carols.

Just to be clear: people with tinnitus hear these sounds when there are no actual Christmas carols, or insects.

P. JASTREBOFF: Basically, it’s a perceiving of a sound. It is not created by hearing. So, tinnitus is phantom auditory perception. 

Some people with tinnitus aren’t particularly bothered by it; for others, it generates an intense emotional response. One treatment is called Tinnitus Retraining Therapy, or T.R.T., which was developed by Pawel Jastreboff and a colleague, Jonathan Hazell. It is a combination of psychotherapy — including stress management and relaxation exercises — and sound therapy, like using white noise to mask the tinnitus sound.

P. JASTREBOFF: So, even if you’re hearing the sound, this signal is not spreading to the emotional system, and it’s not causing an emotion, and it’s not causing any reaction. 

And this is the therapy the Jastreboffs have been trying with patients suffering from misophonia. They’ve had at least some success with about 80 percent of their patients, and early clinical studies have shown promise. Even for the majority of us who don’t suffer from something like misophonia or phonophobia, it’s still easy — at least I’d argue it’s easy — to appreciate that noise can generate strong emotions. Though not always in predictable ways.

Just as one man’s trash is another man’s treasure, the scale of noise appreciation is a sliding scale. The very same chewing sound that may torment someone with misophonia can delight someone who experiences A.S.M.R. Your favorite song in the world might be my least favorite. You can tell a lot about how someone feels based on whether they describe something as “sound” or as “noise.”

HAGOOD: So, the definitions of noise and sound are often debated in the field of sound studies. 

That, again, is Mack Hagood, the sound scholar (or maybe the noise scholar).

HAGOOD: When most people talk about noise, the argument is, the world has gotten noisier and we need to do something about it. And it’s true. Some of these sounds are objectively damaging to our health. But history doesn’t just change the sounds around us. It also reshapes how we define what’s noise. History also reshapes the senses themselves. What actually sounds pleasing and displeasing to us, how we listen, how we learn to listen, how we engage with sound. We’ve been trained by technologies like the telephone and headphones to listen closely and evaluate sounds in a particular way that’s different from in the past. And so we have this new pressure to survive through our ability to concentrate. And that’s when noise starts to seem like a real big problem. 

Here’s one very reductive definition of sound versus noise. Sound is something I make, or choose to hear; noise is something you make, or choose to hear. This isn’t a real definition; I just made it up. But I don’t think it’s all that wrong. If you look at surveys where people are asked what sounds they hate the most, the answers aren’t very surprising: loud interruptions like garbage trucks and sirens and car alarms. Also snoring. And: loud phone conversations — other people’s loud conversations, of course, not our own. Our own noise rarely bothers us.

This is good evidence that when a noise does bother us, it’s not necessarily the sound waves themselves. It’s what they represent — or maybe fail to represent. Consider the one-sided cell phone call — or, as it’s been named, the halfalogue. Why is that so much more annoying than hearing two people talking? Some academic researchers asked that very question and came up with a plausible answer: when we hear just one side of a conversation, our brains are compelled to fill in the missing information. Imagine reading a book with every other page torn out. The cell-phone halfalogue is noise we can’t ignore. And because we can’t ignore it — or control it — we find, as Seneca wrote a couple thousand years ago, that our very autonomy has been challenged. Coming up after the break: just how costly is noise?

DEAN: The first experiment is really designed to answer this question of, what is the impact of noise on productivity?

And: let’s hear from someone who just gets it.

BRONZAFT: If you are seeking assistance with a noise problem, you can contact me directly.

I’m Stephen Dubner; this is Freakonomics Radio. Thanks for putting us in your ears. We’ll be right back.

*      *      *

When you think about sound and noise, it’s easy to point out all the detriments. But as with anything that exacts a cost, there are benefits as well, often massive ones. Consider all the music you love, the conversations you have, the thrill of being in a big crowd during a celebration. We should also appreciate the strategic application of sound for the benefit of our species, and other species. We already mentioned how scientists at the Great Barrier Reef drew fish back to dying reefs by playing audio of a healthy reef. And hear this: scientists at the University of Washington recently began using ultrasound “acoustic tweezers,” that can manipulate a kidney stone and help clear it through the urinary tract. That said, it is wise to be aware of the downsides of noise, especially noise that we can’t control.

TYACK: People have studied children, for example, in Munich, both in a place where there was an airport and where an airport was going to be built. 

That, again, is the behavioral ecologist Peter Tyack.

TYACK: And when they closed the old airport and moved to the new airport, the children in the new area all of a sudden had cognitive problems related to learning with language tasks. It wasn’t loud enough to affect their hearing. It didn’t affect their immediate health. But there were problems with, say, in school, being able to understand complicated linguistic problems. 

Other research has found that airport noise has negative effects on various cognitive and physical dimensions, even after adjusting for socioeconomic factors and pollution. Other studies have looked at the noise generated by highways and subways.

BRONZAFT: Let me talk about my work on subway noise. 

That is Arline Bronzaft.

BRONZAFT: Professor emerita of the City University of New York. And I do research and write on the effects of noise on people’s mental and physical health. 

She’s also on the board of a nonprofit called GrowNYC, which runs environmental programs in the city.

BRONZAFT: And we also have a section on noise, in which we give advice to people on how to lessen the noise levels in their lives. But if you go to our noise site and you are seeking assistance with a noise problem, you can contact me directly. 

DUBNER: Now, you’re not saying that you go down to 3-1-1 and take the calls. You’re saying this is a separate channel. 

BRONZAFT: Actually, the people who contact us at GrowNYC have not been able to get the assistance through 3-1-1, through their public officials, with their managers of their buildings or their landlords. And I get the most difficult cases. Do people contact me? The answer is yes. 

The board members of GrowNYC are appointed by the mayor; Bronzaft is on her sixth. She is a legend in the world of noise research. But that was not her original plan.

BRONZAFT: Noise found me. 

In the 1970s, Bronzaft was teaching environmental psychology at Lehman College, in the Bronx.

BRONZAFT: A student asked to speak to me after class and said, “My child goes to a school next to an elevated train. And the noise from that train disrupts the classroom every four, four-and-a-half minutes. And we intend to sue the City of New York in order to improve the education of our children, because we believe the train noise is disrupting their learning.” To which I said, as the wife of an attorney, “You need data to prove that the children aren’t doing as well in that class.” And she said, “Will you help us?” 

This turned into Bronzaft’s first study on the effects of noise, at P.S. 98 in Upper Manhattan. One side of the school building faced a nearby elevated subway; the other side faced away. Bronzaft matched second-, fourth-, and sixth-grade classrooms on the quiet side and on the noisy side, where a passing train would push the sound readings from 59 decibels to 89 decibels. Then she compared the average reading scores from the two sets of classrooms.

BRONZAFT: And the children exposed to the transit noise were nearly a year behind in reading by the sixth grade, and the teacher had difficulty teaching.

The published paper got a lot of attention.

BRONZAFT: But I had not really responded to the mother’s request. She asked me to help the children. And so, I went back to the school, and with the aid of the principal, we went to the Board of Education and we asked for acoustical ceilings in the classroom, and I was able to persuade the transit authority to choose the site adjacent to that school to test out a new procedure to quiet the noise on the tracks. And they agreed. And when I looked at the reading scores in the now-quieter classroom and compared it to the reading scores of the children on the quiet side of the building, it turned out they now were the same. 

It’s worth noting that Bronzaft’s subway research, as with similar studies at airports and elsewhere, have some limitations. For one thing, Bronzaft couldn’t randomly assign students to the noisy versus quieter classrooms. There were also relatively few classrooms to choose from, so there might have been some natural variation. In any case, this kind of research led to Bronzaft becoming a scholar of both the physical and psychological aspects of this issue.

BRONZAFT: Sound is a physical phenomenon. Noise is a psychological one. Sound comes into the ear. It travels to the brain and it registers in the temporal lobe. And then we further identify what the sound is. But noise lets you know whether that sound is disturbing, is bothersome, is hurting you, and that’s a psychological phenomenon. 

DUBNER: Which part disturbs us more about noise — the intrusion itself, or the fact that in most cases, we don’t have an ability to control it? 

BRONZAFT: So, I would say both. The actual sounds that you’re hearing is disturbing your sleep. And there’s a phenomenon in psychology called learned helplessness. It means no matter how I try, I can’t stop it. And that is also costly to one’s health. 

DUBNER: Can you talk a bit more about any trade-offs you can think of in noise reduction? For instance, New York City subways are still, as far as I know, steel-wheeled, which are noisier than rubber. So, then I get to thinking, well maybe steel wheels are safer or they’re more durable or whatnot. But there is no such thing as a free lunch.

BRONZAFT: I understand that companies are in business of making money. But what about the medical costs for people who live near noisy airports? And the data have demonstrated increased cardiovascular disorders for people who live near airports. Doesn’t that cost money? So, if you asked me, do the companies that produce the noise through their products, through their activities, are they holding the upper hand? Yes. But we’re paying for it, because medical costs in this country are high. So are educational costs. Remember, if the children were a year behind in reading, how much would it have cost to remediate their learning deficits?

In Bronzaft’s work as an advocate for New York citizens, she’s dealt with all sorts of noise complaints. Among the most common are pervasive bass sounds.


DUBNER: Are you in the mood to imitate a pervasive bass sound?

BRONZAFT: You can do that better than I. I could speak to bass sounds. 

DUBNER: Would you please?

BRONZAFT: Yes. If you live above a bar or a music establishment, you not only hear the bass, but if you’re lying in bed, you will feel it. The bass sounds are low-frequency sounds. Usually, we talk about noise in the mid-range of the frequencies, but when you talk about bass music, you’re talking low. Bass sounds have taken up more of a center stage today with wind-turbine introduction. Because wind turbines are now seen as an alternate source of energy.

However, the wind turbines generate the low bass sounds. And the laws that have been passed to regulate the sound levels of wind turbines have been on the A-scale, the mid-range, where we commonly measure the levels of sound. And they’ve sort of ignored the low bass. And so you find a great uproar from citizens living with turbines saying they don’t want them.

Coming up after the break, how much does noise pollution cost us? I’m Stephen Dubner and you’re listening to Freakonomics Radio. We’ll be right back.

*      *      *

We’ve been talking today about noise pollution — some of the causes and a few consequences. Let’s pull back now and get a sense of the overall cost to society. What does the economics literature have to say about that?

Josh DEAN: It really doesn’t exist. 

That’s Josh Dean.

DEAN: I’m an assistant professor of behavioral science at the University of Chicago’s Booth School of Business. 

So, economists really haven’t calculated the costs of noise pollution?

DEAN: There’s a very large history of psychologists using noise in laboratory experiments, both to understand the impacts of noise per se, but then also using noise as a kind of tool in order to understand other things, like how our working memory works and how our attention works. But there’s really nothing in economics and there’s really not much in terms of how this affects economic outcomes. I think I, in scouring the literature, managed to find three other papers that have looked at this question, including one from 1935 with 20 subjects. 

Dean scoured the literature because he had become personally interested in the topic, while working on a different project, in India.

DEAN: I was living in Delhi and I was in a cafe trying to work, as lots of grad students do. And I kept getting distracted by all of the horns honking and the people selling things. And I had a light bulb moment where I realized if I’m having trouble doing this, inside of this nice cafe, what is this like for people who have to live and work in this kind of noise without even the minimal escape that I’d been able to find? 

DUBNER: And when you think about noise as a research subject, what made you go to productivity versus, let’s say, the health outcomes, physical or mental-health outcomes, or other potential downstream effects of noise? 

DEAN: Some of it is just that you want something that is relatively easily measurable and quantifiable. And productivity is nice in that way. And it’s particularly nice in that you can put a dollar value on it. If you tell someone, “The noise in your factory is causing a 5 percent decrease in productivity,” that means something to them in terms of making the decision of whether to abate noise. If you tell people something like, “Twenty-five percent of your metal workers have disabling hearing loss,” you have to take another step of trying to convince people that that means that you should care about this. And so productivity is an easier outcome both to study and to then use to persuade people to care about the problem. 

DUBNER: Wow. That was a very compelling, if depressing, answer.  

DEAN: Isn’t that what economists are supposed to be good at? 

So, Josh Dean set out to personally expand the scant economics literature on noise and productivity.

DEAN: There were three research questions that I was interested in answering. The first is kind of, is there an effect of noise on productivity? Full stop. And if so, how big is that? 

DUBNER: In other words, you were not believing the 1935 paper. 

DEAN: Well — I would like some more robust evidence. And so, that’s the first goal. And then the second goal is to understand what is the underlying mechanism by which noise affects productivity. So, there’s this psychology literature that suggests possibly something like inhibiting attention or working memory, but it could also be something like reducing the effort of workers because they don’t enjoy being put in noisy working conditions. And depending on what the mechanism is, that is going to lead to different conclusions about where we should expect this to matter and what the right policy response should be. And then the last question is to understand how much scope there is for workers to adapt to noise by doing things like purchasing hearing protection or avoiding noisy working conditions. 

How workers adapt to noise — that is something most of us struggle with at some point, especially if your work involves any cognitive tasks. Some of us struggle more than others — and I am raising my hand here. I’ve always been badly distracted by noise, even the casual background conversation that most people seem to power right through. When I first started working in newsrooms, I wore foam earplugs all day every day (and yes, I was ridiculed for it).

Later came noise-canceling headphones, a total godsend with the additional benefit of signaling to co-workers that you don’t want to be interrupted. Noise-canceling headphones have since increased in popularity, as is evident when you walk through any public space these days. A team of scientists in Singapore has even invented what’s being called “noise-canceling headphones for your apartment.” It’s an array of speakers that emit sound waves calculated to cancel out the incoming noise. So, the appetite to mitigate the noise of modern civilization is plainly strong; as for the exact cost of all that noise? That is what Josh Dean wanted to figure out. So, he set up a study with two main experiments.

DEAN: So, the first experiment is really designed to answer this question of, what is the impact of noise on productivity? And to do so, I recruit a group of manual laborers who are used to working in noisy factory conditions, and bring them to a textile training facility.

This facility was just outside of Nairobi, Kenya. There were around 100 workers in the study, and they were being trained to sew pockets for clothing.

DEAN: And then while they’re performing a standard sewing task, I randomly expose them to engine noise, which we think is representative of some of the major types of noise you might worry about — thinking loud industrial machines, think cars on the street. 

Significantly, engine noise also doesn’t have any informational content. It’s not like that one-sided cell-phone call you’re subconsciously trying to participate in; it’s not even like overhearing a T.V. or coworkers chatting. Now, you may be wondering how Dean was able to randomly expose these workers to engine noise.

DEAN: So, what’s nice about this training facility is that they also train automotive mechanics, and for that reason, they have car engines mounted on wheels. So, I’m able to both randomly assign workers to rooms and then randomly assign which room is noisy. 

DUBNER: And what do you do about the exhaust? I assume you want to isolate the noise and not the air pollution. 

DEAN: Right. So, we have the car engine out in an open courtyard with the exhaust pointing away from any access points to the room, and then to double-check that none of the exhaust accidentally bleeds in, we measure the CO2 levels of the room. 

DUBNER: How many decibels louder is the room with the engine than the quiet, quieter room? 

DEAN: So, it’s seven decibels louder. 

DUBNER: Oh, that’s not very much. 

DEAN: Well, decibels are tricky to interpret because they’re on a proportional scale. So, three decibels is the detection threshold of human hearing, and a 10-decibel change is perceived as twice as loud by humans. So, it’s not very intuitive. I think the more intuitive way to think about it is, if you go from having a kind of normal dishwasher going in the background in the control condition to having a vacuum cleaner right next to you. 

So, these textile workers would spend a few days in training and then get randomly assigned to rotate through noisy and less-noisy rooms. They were paid for each pocket they sewed as long as it was deemed acceptable by an impartial judge. After two weeks, Dean had enough data to see how the noise affected productivity.

DEAN: So, what we find is that if we double how loud the room feels, the workers are about 5 percent less productive on this task. And just to put that number in perspective, we also randomly assigned how much we were paying participants based on their production. And there, if we double their payment from five shillings per pocket to 10 shillings per pocket, that only increases productivity by around 3 percent. 

DUBNER: So, if you had to describe the magnitude of this effect in lay terms — and since we’re talking about clothing, let’s put it in small, medium, large or extra-large — how would you describe the change in productivity, then? 

DEAN: I would say a medium-sized effect relative to the other means we know of affecting productivity. There’s another great paper that looks at the effects of an intensive, months-long management intervention in a textile factory in India. And what they find is that that increases output by 9 percent. And so, this 5 percent effect is about in line with the other means that we have of affecting the productivity of workers, which suggests that it’s an economically meaningful environmental input. 

There was another tangential finding from this experiment that was of interest to Dean: when it came to being distracted by noise, it didn’t seem to matter how good a given worker was at sewing pockets. In other words, a high level of skill didn’t lessen the noise distraction.

DEAN: Right, exactly. If you have a distractor, you’ve got to slow down a bit to focus on what you’re doing to make sure that you’re doing it right. And that slowdown factor just appears to be constant. 

And then there was the second experiment within Dean’s study. This one was meant to understand why productivity falls in noisy conditions. Was it about the cognitive strain, or perhaps due to decreased motivation or physical weariness? In this case, Dean ran a condensed version of the first experiment but rather than sewing pockets, the workers performed tasks that tested skills like attention and working memory — as measured against a placebo task that didn’t involve any cognitive input at all. The result? Workers did slightly worse on the cognitive tests and slightly better on the placebo task.

DEAN: So, what I think we learned from the two experiments is that noise can impact productivity and that this seems to come through this cognitive channel.

DUBNER: So, how much can you generalize, or would you want to generalize, these findings to productivity in other areas where noise is a factor? Let’s say an open office with conversations going on in the background, or a hospital with dinging alarms and so on.

DEAN: There’s two questions you have to ask yourself. The first is, how similar is the noise? And in particular, along those two dimensions, of informational content and how constant the noise is. So, if you are extrapolating to a setting like an open office, you could imagine that the effect would actually be much worse because the noise that you’re being exposed to has informational content associated with it. So, I’m working on selling a product or a spreadsheet and I hear the person in the cubicle right next to me talking about basically the same thing. That’s much harder for our attention to filter.

And then the other is the task. This is why it’s important to know that the mechanism really does appear to be impairing things like attention and working memory, because that lets us think about the fact that the places we should expect this effect to show up are tasks that have demands on attention. 

DUBNER: I just want you to talk for a moment about noise or noise pollution, as what an economist would, I assume, call a negative externality, yes? This is something that I have to put up with that I am not causing. And yet, the person that’s producing it is not paying a price. So, can you just draw that, scenario for me and how you think about it as an economist in the modern world that’s producing a lot of noise? 

DEAN: Sure. I think, actually, we don’t have to just even think about the modern world. There’s this great book on the history of noise by Goldsmith, and he talks about the first noise-pollution ordinance to manage this externality where I’m creating noises that are beneficial to me but bother all of the people around me. It dates back to the 6th century B.C.E. 

DUBNER: Wow, no joke. 

DEAN: It was a Greek colony, and they had such a problem with their potters and tinsmiths and tradesmen making noise and bothering people that they banned them from working in the city. Another example that I really like is, in 1787 when the founding fathers were working in the Pennsylvania State House on the Constitution, they apparently spread dirt on the cobblestone streets outside in order to prevent themselves from being distracted.

I think noise is one of the oldest externalities that we’ve had to deal with, and it is a natural byproduct of a lot of things that you want to do. It’s a byproduct of getting around. It’s a byproduct of making things, it’s a byproduct of entertainment. And just by its very physical nature affects everyone who is around you. And it’s something that you don’t really think about or you don’t fully appreciate the impact that it has on other people. And it’s a problem for governments and those who try to manage externalities have been dealing with literally since ancient times.  

The U.S. used to have a federal Office of Noise Abatement and Control, as part of the E.P.A. But it was defunded in the early 1980’s, which shifted responsibilities to state and local governments. So, there are rules on the books in most places that limit, for instance, when construction can happen and how loud it can be. Same for garbage trucks, and bars, and even personal lawn-mowers. There are even prohibitions against ice-cream trucks playing their jingle once they’re parked at the curb. But, of course, there’s a big difference between having a noise code and enforcing it. In New York City, between 2010 and 2015, there were about 1.6 million noise calls via the 3-1-1 complaint line. Only 1 percent of the cases where the N.Y.P.D. confirmed noise resulted in a summons. Josh Dean again:

DEAN: So, one very economics-y thing that I worry about is that noise is very susceptible to a race to the bottom. You get louder, which means that in order to compensate, I have to get louder, which then makes you get louder. Some car manufacturers in India have recently started advertising that they can make their car horns extra loud for you. There’s no intrinsic reason you need a really loud car horn, right? You have a really loud car horn because everybody else has loud car horns. And this kind of strategic interplay means that you can get noise levels that really quickly spiral out of control.

HAGOOD: Fighting sound with sound is what I see people doing with these different kinds of technologies, sort of pacifying the space around them in order to maintain their own control of their own attention and their own state of mind.

That, again, is the sound-and-noise scholar Mack Hagood. His concern about a race to the bottom isn’t so much that the world will get unbearably loud. It’s that we will focus on individual, behavioral problems at the expense of wider, structural solutions.

HAGOOD: I mean, is it your jerk coworker who slurps ramen noodles? Are they the problem or is it the open plan office that someone decided was a lot cheaper and more efficient to design? Have we fallen into certain patterns where we’re so used to controlling the sounds around us that we don’t think to take off the headphones? And this is the real problem, is there can never be enough control. The more control we get, the more sensitive we become to noise. And if we could magically wipe out all the sound in the world, then we would hear the sound of our own tinnitus, because tinnitus gets louder in a vacuum. So, I think we just need to think about this path, because I do not think happiness lies in that direction.

In which direction does happiness lie?

BRONZAFT: You will find that one word would really cut back on noise intrusion, and that’s the word “respect.”

And that again is the noise whisperer Arline Bronzaft.

BRONZAFT: I think if respect came back and people understood that their sounds can intrude on the lives of others, I think the 3-1-1 calls would drop drastically.

To be clear, Bronzaft is not advocating for silence or anything close to it.

BRONZAFT: Even though I write a great deal about noise and speak about it, I am trying to say to people, “Listen, there are such good sounds out there.”

And as the pandemic subsides, some of those good sounds are coming back.

BRONZAFT: I do not want the children cheering on the Macy’s Day Parade to stop cheering them on. When the ball falls on New Year’s Eve, I want the people to shout out and enjoy the moment. I’m not asking for the music venues to shut down. I’m not. I think the vibrancy of the city, the parade, the ball falling, the music that we hear in our city, these are all positive things. So, let’s not lose sight of the various wonderful sounds the city does have. Just tune down the ones that are intrusive and harmful to our health.

*      *      *

Freakonomics Radio is produced by Stitcher and Renbud Radio. This episode was produced by Daphne Chen. Our staff also includes Neal CarruthGabriel Roth, Greg Rippin, Zack Lapinski, Rebecca Lee DouglasMorgan Levey, Julie Kanfer, Ryan Kelley, Katherine Moncure, Jasmin Klinger, Eleanor Osborne, Jeremy Johnston, Daria Klenert, Emma Tyrrell, Lyric BowditchJacob Clemente, and Alina Kulman. Our theme song is “Mr. Fortune,” by the Hitchhikers; the rest of the music this week was composed by Luis Guerra. You can follow Freakonomics Radio on Apple PodcastsSpotifyStitcher, or wherever you get your podcasts.

Read full Transcript


  • Arline Bronzaft, professor emerita of the City University of New York and board member of GrowNYC.
  • Josh Dean, assistant professor of behavioral science at the University of Chicago’s Booth School of Business.
  • Mack Hagood, scholar of sound at Miami University in Ohio and host of the podcast Phantom Power.
  • Pawel Jastreboff, co-founder of Jastreboff Hearing Disorders Foundation Clinic and professor emeritus at Emory University School of Medicine.
  • Margaret Jastreboff, President of the Jastreboff Hearing Disorders Foundation Clinic.
  • Peter Tyack, behavioral ecologist at the University of St. Andrews.


Episode Video