Science Friday - Air Conditioning, Face Recognition Neurons. Oct 8, 2021, Part 2

Episode Date: October 8, 2021

The Hot And Cold Past Of The Air Conditioner In the Northeast, the leaves have started changing colors, heralding the season of pumpkins, sweaters, and the smell of woodsmoke. But in some parts of the country, the heat hasn’t let up. In cities like Dallas, Phoenix, and Miami, temperatures were up in the high 80s and low 90s this week—and with climate change, the U.S. is only getting hotter.  But humans have come up with an ingenious way to keep the heat at bay: air conditioning. Widely considered one of the greatest engineering achievements of the 20th century, the technology has transformed how and where people live—and it’s prevented countless deaths. But it comes at a cost, and if we’re going to keep up with a warming climate, we’re going to need some other tricks to stay cool.  Like what you hear? Dive deeper with some of the sources we turned to while reporting.      See A Familiar Face? Thank These Brain Cells What happens when you see a familiar face? Light reflected from the face enters your eye, is focused onto the retina, and a signal travels up your optic nerve. But what exactly goes on in your brain after that is still somewhat mysterious.   Recently, researchers reported in the journal Science that they had identified a group of brain cells that seem tuned to respond only to familiar faces. The theory is that the specificity of those neurons helps to speed up processing of potentially important visual information. The work was done in monkeys, but the researchers are currently trying to identify similar brain structures in people.   Sofia Landi and Winrich Freiwald, two of the authors of the report, join Ira to talk about the research, and what it may tell us about how the brain and memory are organized.  Subscribe to this podcast. Plus, to stay updated on all things science, sign up for Science Friday's newsletters.

This is Science Friday. I'm Iroflato. Later in the hour, finding brain cells that seem tuned to recognize familiar faces. But first, here in the Northeast, the leaves are turning, and we can look forward to pumpkins, sweaters, and the smell of wood smoke. But in some parts of the country, a full week into October, the heat just hasn't let up. In Graham County, we're calling for highs in the mid-80s, upper 80s in the old peblo. We'll be around 86 today, but then we turn even warmer for the heat. Thursday, Friday, and 90s to the south and west from Heelabinti Yuma.

Craig, it seems like summer is trying to hang around a little bit. Get out of here, sorry. Yeah, trying to hang on just a little bit there. It'll give up eventually, right? With climate change, this country is going to keep getting hotter, and often the only way to survive is with air conditioning. Named one of the greatest engineering achievements of the 20th century by the National Academy of Sciences,

air conditioning has completely transformed how and where people live. And so in collaboration with St. Louis Public Radio, we bring you a look back at more than a century of AC and what it means to live without it. Here's Science Friday's Elefetter with that story. In the summer of 1904, visitors to the World's Fair in St. Louis were in for a rare treat. And it wasn't the giant Ferris wheel or the elephant made of almonds, though those were both fantastic. It wasn't the obvious kind of fun, really, or anything you could see, or touch, it was something that you felt. So imagine this.

It's August, and you've come all the way to St. Louis to see the absolute cutting edge in human achievement. Maybe you checked out the aeronautics competition, or the X-ray machine that could look right inside you. But by late afternoon, you've been wandering for hours. You're milling through these crowds, and it's hot, and it's humid. You're just melting.

when you step into this one building, the Missouri State Building. And inside, it feels so good. Because tucked in the basement is a 30-ton refrigeration plant, allegedly capable of dropping the temperature to just 70 degrees on a 90-degree day. Engineers gushed about it in that year's Journal of Ice and Refrigeration. It's 60-horsepower motor, it's horizontal, double-acting, ammonia compressor and the delight of those who experienced it. Visitors not aware that the building was artificially cooled were struck with wonder

and were unable to account for the very perceptible change felt in the temperature. Now, artificial cooling, it wasn't totally unheard of at this point. The trading room at the New York Stock Exchange, the Cornell Medical School's dissection room, both of them got their own cooling systems in just the last few years. But in 1904, for most people, artificial cooling. would still have been a novelty. Something they might have heard about, but wouldn't have experienced for themselves.

Local newspapers loved the installation, in some cases devoting multiple paragraphs to it. The St. Louis Republic wrote, quote, entrance into the Missouri building from the glaring heat outside will be instantly followed by the most delightful relief from the oppressive weather encountered in promenading the grounds.

The relief did not last long. Just two weeks before the end of the fair, the Missouri State Building burned to the ground. It actually happened while the fair was still going. Thousands ran over to watch the building burn. And though the fire brigades did their best, they couldn't save it. The story of air conditioning, though, that was just beginning. In many ways, St. Louis was the perfect place to introduce people to artificial cooling.

Sheila Farzan is a reporter at St. Louis Public Radio. It sits right at the spot where the Mississippi and Missouri River, come together. And in the summertime, the combination of heat and humidity can feel almost tropical, like breathing through a warm, wet towel. And for a long time, people just had to find workarounds, turn on a fan, sit on the porch, sleep outside in city parks. And then came air conditioning. Many people credit Willis Carrier as the inventor, but his systems were really building on what others had done before. Willis Carrier was an interesting guy because he was a was somebody who had the right, call it nose, and he was in the right place at exactly the right

time. Salvatore Basel is the author of Cool, how air conditioning changed everything. Carrier was a young engineer working for a company in Buffalo that made heating and ventilation systems. And in 1902, he got an assignment. A printing firm came to the company with a problem, that summer humidity was causing paper to swell, and that would mean that it would print incorrectly. And rather than a crisp image, they were getting a blur. They needed something to control the humidity. So Carrier got to work.

At first, he tried chemical drying, using a bunch of desiccant. But that contaminated the air with salt droplets, and resulted only in, quote, ruining two perfectly good pairs of expensive shoes. So he changed tactics. He knew that if you lower the air temperature, it'll bring down the humidity, too. It took a few more years of experimenting with cool air, but finally, he cracked it. In 1906, he landed on the basic model he'd use for decades to come.

Carrier realized that he was onto something, and he borrowed a phrase that was being used in cotton mills, air conditioning. Not air cooling, air conditioning. Because for Carrier, this wasn't just about making it cold. It was a top-to-bottom makeover of the air with four essential components. Cleanliness, control of humidity, control of temperature and circulation. This was from a promotional video from the 40s. These would never have been commercially possible, but for the discoveries and air conditioning developments of Dr. Carrier and his associates.

In the early decades, air conditioning was mostly used in factories. Not for the comfort of workers, of course, but for the quality of the product. Like macaroni, has to be dried at just the right humidity. Otherwise, it would sour or sometimes crack. Or if you're spinning cotton, it can't be too dry. Otherwise, the thread will break. On the other hand, something like chocolate cannot be manufactured in a hot environment at all. Many chocolate manufacturers would actually close down for the whole summer.

Same with chewing gum. It was in those days too sticky to work with during the summer. But with systems like carriers, manufacturing could chug along. Carrier tried to promote air conditioning just for comfort, too. For years, Carrier would say, why not have a house that is available for you all the seasons of the year so that you could really live there in the summer rather than going away to the seashore?

No one was interested because hot weather was something that you put up with. God gave it to you and you had to deal with it. There was a very Victorian sensibility that hot weather was simply a given. You would have a fire against cold, but as far as heat, you lived through it. It was also just very expensive. The first modern home air conditioner was another company's, frigidaires, and it weighed 600 pounds, cost as much as a car, and didn't work all that well. But then Carrier found the perfect customer.

Movie theaters. Movie theaters were in a very bad way by the 1920s. They were famous for being places where the air was unbreatheable. In 1925, Carrier installed a system in New York's Rivoli Theater. Now, theaters in those days could get very hot, so audiences had all come prepared with fans. And even though the system was starting to run, it hadn't quite kicked in, and people were fanning away. Carrier was standing at the back of the auditorium, very nervous, but then they began to feel the cool, and he noticed all the fans gradually beginning to stop.

Also there that day was Adolf Zucor, the president of Paramount Pictures. And after seeing this incredible display, he walks up to Carrier and tells him, yes, the people are going to like it. And this was actually a very unheralded moment, because this was the first time in human history. that the average person for the price of a movie ticket could go somewhere and become cool during the hottest summer heat. That was a revolution. Bang.

All of a sudden, every other movie theater in the United States had to catch up. Yes, you lucky people, just sit back for a moment, relax, and notice the delightfully clean, cool, and refreshing atmosphere of the scientifically-eastern atmosphere of the scientifically Air Conditioned Theater. This is from the 40s. It would run before the show started. I love that this is the selling point.

It's not the great movies you're going to see. The key is it's going to be cold. So at first, air conditioning was just about good times and macaroni. But pretty soon, it went from luxury to necessity. The real shift happened after World War II. Air conditioners were becoming more affordable. And in the 50s, there were a lot of new houses being built cheaply. so think, poorly insulated, with these big modern windows, basically what one writer at the time called TV-equipped hotboxes.

Air conditioning them was essential. And over time, mortgage lenders and insurers went from treating air conditioning as an unnecessary amenity to covering it, or even requiring home builders to plan for it. And by the late 70s, about half of U.S. households have systems installed. And air conditioning changed how and where people lived. Skyscraper's would be deeply uncomfortable without air conditioning, especially on those upper floors. The Sunbelt states, like Florida, Texas, and New Mexico, they start growing much faster than many other parts of the country. And a lot of people think air conditioning allowed that to happen. And for those who had air conditioning, it wasn't just keeping them comfortable.

It wasn't just letting them sleep soundly on summer nights. It was actually saving their lives. Which brings us to St. Louis in 1980. I started working for St. Louis two months out of high school. It wasn't, that was 1977. Gary Ludwig is the fire chief in Champaign, Illinois. We met up at his house one weekend in August. And Gary told me he originally enrolled at St. Louis University to become a doctor.

But his scholarship money wasn't enough to cover tuition. So at 18, he joined a federal program that trained. people to be first responders. Sometimes you'd be on a fire truck and sometimes you will be in an ambulance. And a lot of times I wound up finding myself on an ambulance because they were short-staffed. A year later, Gary was hired as a paramedic captain. And he was just a kid, really, learning on the job. One of the first times he went out, he says he helped carry a woman who was in labor down six

flights of stairs. And she's having this baby in the back in ambulance. And I have no idea how to deliver a baby. and I think I was more nervous than the mother was. By 1980, Gary had a few years of experience under his belt. He used to drive this station wagon packed with medical equipment around St. Louis. And when there was an emergency, he was usually the first person there, even before the ambulance arrived. But on July 1st that year, the temperature started rising.

On a typical July day in St. Louis, you get a high of about 80 degrees. That day in 1980, it reached. 105. And that was just the beginning. For the next 19 days, temperatures were in the upper 90s and low one hundredths, almost every day. Yesterday set a record for power use. 108 degrees today that beat the record all to smithereens. This is what summer should be, starting off in May about 80 and peaking off in August about 98 degrees, but we have been nowhere near normal this year. It would become one of the worst heat waves in recent history. with extreme heat stretching all the way from Texas to Washington, D.C.

And in St. Louis, as the temperatures rise, the calls start coming in faster and faster. So the emergency rooms are starting to fill up. There is one day I know that we hit 350 calls for EMS in a 24-hour period, which was probably 200% or more above our normal limit. So when you have something like that, you don't have enough resources. You have calls stacked up sitting there waiting for someone to dispatch an ambulance. So Gary was working these long shifts, sometimes 16 hours at a time, running from one call to another. And he still can't forget some of the things he saw.

This one time in particular has really stayed with him. In a warning to listeners, some of what you're about to hear is disturbing. We break the door down. We go inside, and sure enough, we find... A person on a bed. And as I said, I've seen many dead bodies in my career, but I have never seen a dead body like this before. Because there was no human farm there at all. The body had basically turned to jelly.

And to our shock, and I say shock, there's a lady laying next to him. And she's delusional. She's suffering either from heat or whatever. we don't know what she's suffering from. So we're able to load her up on a stretcher and get her out the door. And as we're taking her out the door, she turns and says, are you going to take him also? And in going to call after call, Gary quickly notices a pattern. The victims of this heat wave tend to be older, lower income, and they don't have air conditioners.

I don't know how many times I would walk in and I would find some elderly person. Again, their home will shut up and they're sitting in a chair. in front of a fan that's all they had to cool themselves and they're dead. You know, the fan, all this is doing is blowing hot air on them. Their body temperature still rose to 105, 100, 600, 700, 7, 800, 8, 110 degrees. We found some with 115, 16 degree heat indexes on their body. At least 153 people died in St. Louis during the 1983 heat wave. So many that the local newspaper, the St. Louis Post-Dispatch, began printing the names and ages

of the dead. The city medical examiner told the paper they were running out of places to put the bodies. Unnecessary deaths from the lack of air conditioning would continue, unfortunately, up until this day. Ella Fetter continues with the story of AC after this short break. This is Science Friday. I'm Ira Flato. We're talking this hour about how air conditioning has transformed America. Back to Science Friday's Ella Fetter with that story. An air conditioner works by taking time.

heat from inside your home or your office or your car and dumping it outside. Usually it does that with a refrigerant, a kind of liquid that easily evaporates. The liquid runs through the air conditioners pipes, and as it evaporates, turning from liquid to gas, it draws the heat out of the air, cooling the air down. But then, that heat needs to go somewhere. So the air conditioner squeezes the refrigerant back down into a liquid, forcing it to release all that heat. heat again and throws that heat outside. And that's the cycle. Suck the heat from the inside, dump it outside, over and over again. I like to imagine a very industrious hamster running back and forth with buckets of heat. Our fact checker Lauren Young suggests that you imagine the hulk,

hulking out with heat, then compressing back into a human and letting that heat out again. Whatever works for you. Your body works in kind of a similar way, except for instead of a refrigerant, it's sweat. When you heat up, the sweat evaporates off your skin, taking the heat with it. And your body, as it circulates your blood, keep sending heat to the surface. Hot blood to the skin, cooled blood back down into your body. On and on, with sweat, the cooling engine at the heart of it all. But sometimes your body gets so hot and dehydrated, you actually stop sweating. And that's when you're in real trouble. Heat stroke. Internal temperature gets to be 105, 100, 100, 600, 7, 108 degrees.

And since you stop sweating, what happens is that your body has no more ability to calm itself down, and that's why the body temperature rises. So it cooks your brain is what it does. It virtually just cooks your brain, and it also impacts all your organ systems, the fact, you just die. If you look at deaths in the U.S. over the decades, you see a consistent pattern. Most people die in the winter when it's cold. Flues and other respiratory diseases spike and heart attacks,

but they also die when it's extremely hot. And so researchers at the University of Virginia decided to look at data going back to the 60s. And they saw that at first, predictably, whenever there was very hot in humid weather, people died. They saw a spike in excess deaths. That was true in the 60s. That was true in the 70s.

But by the 90s, the pattern fades, more and more people are surviving the heat. And the researcher's best explanation was air conditioning. It's not to say there aren't other factors, like maybe better medical care, but air conditioning, not surprisingly, is a big one. And the researchers found that the more homes with air conditioning in a region, the fewer people die. But while the law generally requires landlords to provide heating, for the most part, air conditioning has been considered optional. Nice if you can get it. Except maybe that's starting to change. I'm really glad we're here today to finish this up. We all know what this bill does and why we're here. Last year, Montgomery County in Maryland passed a bill requiring landlords to provide

air conditioning from June to September. This is Tom Hucker, president of the county council at the final vote. He sponsored the bill. We've had a requirement for heat for a very, very long time because it really is a life or death issue if people don't have heat. And air conditioning has become a life or death issue as well, not just a comfort issue. I recently spoke with Tom, and he says, before this bill, they'd received a lot of tenant complaints about lack of air conditioning or failing air conditioning. And this bill just made sense. For decades, governments have required landlords to provide heat during winter months.

When tenants don't have working heat, unfortunately, tenants perish in the cold. So in a world with climate change and rapidly increasing temperatures year after year, we believe we need to require air conditioning as well. Montgomery County isn't the only one doing this. Arizona law considers air conditioning an essential service, so your landlord has to fix it if it breaks. And Dallas mandates refrigerated air from April to October. But in most places, it's not required, St. Louis included, and someone has to fill in the gaps. Good morning. It's morning, late in August.

Here's Shaila Farsan again from St. Louis Public Radio. I've been driving around St. Louis with a team of air conditioning installers from a nonprofit called Energy Care. It's just past 10 a.m. when we pull up in Jennings, a suburb of North St. Louis. The sun beats down on a little brick house with a peaked roof. Inside, 70-year-old Gloria Van has two fans running on full blast. She's glad to see the techs, and we talk while they work. This heat has really made it hard. It's been a really, really hot summer.

Yes. And at our age, by the time we walk from my door to the car, it was time to pass up. Keeping the house cool is a full-time job for Gloria and her husband David. She tells me about all the ways they've changed their lives and schedules just to work around the heat. Cooking only in the morning or very late at night. baking almost never and constantly moving fans all day from room to room. She says they did have two window air conditioners, one for the bedroom, the other for the living room. But this summer, one broke. The other one started leaking all over the floor.

That's when Gloria heard about energy care. It's one of a handful of nonprofits that helps low-income and elderly people in St. Louis pay for their utility bills. She asked them if they did repairs. They said, no, we'll give you a brand. new air conditioner, or two if you want. I said, well, I don't really want to overdo it. But. You didn't want to ask for two months.

No, right. Right. And she said, no, we'll come. And we'll put two in. I said, thank you, Jesus for God's. It was disgusting. It takes about 20 minutes to install two air conditioners in Gloria and David Van's home.

As the nonprofit workers pack up their tools and paperwork, Gloria pauses in front of the humming little air conditioner and holds out her palm. Oh, wow, you can feel that cool coming off of it. For now, the vans can relax just a little, knowing they won't have to wake up in the middle of the night, drenched in sweat, or work so hard to keep the house cool. Right, right on. Take care now.

By the end of the season, energy care will have installed more than 200 air conditioners in St. Louis. But cooling this city is an uphill battle. Most St. Louis homes are like pizza ovens. They're made of brick, and that means once they get hot, they stay hot. And they're old. Most were built before 1939. Sometimes the only way to survive the heat is to get outside. So why did you guys decide to come to the pool today? Because it was hot and it's not very hot. On a boiling hot August afternoon, I headed to the Fairground Park Swimming Pool. J.C. and Thalc. Alia Uneze and their cousin, Skyler Wilson, were there that day, cooling off. Main advantages of the pool, they say, it's spacious and clean.

You don't really see a lot of bugs, which we like that there's no bugs. Talia, who's 15, and enjoying this remarkably bug-free pool, says they have to keep their air conditioner running all day. But the house is still warm. Our aunt that just turned 85, that house was new. we built when she moved into it. So that was like, I think maybe the 1930s or something. So it's like what she said, there's cracks everywhere so the heat comes in no matter what. I'm on the third story and I have my own air conditioner there that I keep on all day. This pool is actually in the zip code where energy care installs the most air conditioners

at the far northern tip of the city. Like other U.S. cities, there's a stark racial and economic divide in St. Louis. It's cut in half by a street known as Delmar Boulevard. North of Del Mar, neighborhoods are predominantly black and lower income. The south side is mostly white, more affluent. People in some of these south side neighborhoods live up to 14 years longer on average, the north city residents. Maisha Johnson is an environmental justice advocate in St. Louis, and she says some neighborhoods even even feel hotter than others. I noticed that the closer we are to the river seems to be a little hotter.

I never understood that. I thought it would be the other way around. And that's where most of the black and brown communities are. There's some research backing this up. In 2018, a master student in geography used satellite data to calculate land surface temperatures in St. Louis and found a distinct band of heat along the Mississippi River and the downtown corridor. And it's not just St. Louis. This is a pattern. Across the U.S., lower-income neighborhoods, and places with more people of color are often

hotter than wealthier, whiter ones. A lot of that has to do with lack of trees and green spaces, also large roads and building complexes that retain a lot of heat. One study found that historically redlined neighborhoods are on average five degrees warmer. Maisha is worried the heat's only getting worse. It's never been that hot that we can think of. Each year it gets hotter and hotter and the season lasts longer. Climate change will affect regions of the U.S. in different ways. In Florida, sea levels will rise.

California will get drier. And Missouri will get a lot hot. hotter. When you look at the cities that will heat up the most in the next few decades, St. Louis and its suburbs are right at the top. Getting people a few more window air conditioners helps right now. It could even save their lives. But in the long run, Maisha says it won't be enough. As organizations, we can't keep saying, oh, this is what you need, this banday will help. Air conditioning, for all its life-saving, technological wonder, might not be the answer. So remember, air conditioning works by taking the heat from inside and dumping it outside,

which means that as you're cooling down, your neighbors, your block, your city, it's actually getting hotter. There was one study looking at Phoenix that estimated all the heat dumped out by air conditioners was adding up to an extra two degrees in some areas. And then there's the fact that air conditioning in America uses so much energy. Even though newer individual air conditioners can be pretty efficient, in the U.S., all that electricity costs about $29 billion a year. And that's just for home air conditioning. The good news is, at least the refrigerants being used, are less harmful.

Remember in the 80s when everyone was worried about CFCs, the chloro-fluorocarbons, like Freon, which was used as an aerosol propellant and as a refrigerant? Not only did CFCs help carve a hole in the ozone layer, they're also very potent greenhouse gases. So they got phased out, replaced with less harmful alternatives. The bad news is most of the electricity used to power air conditioners comes from fossil fuels, so they're still contributing to climate change. And then there are all the other air conditioners, like in cars running on gasoline, using somewhere from 7 to 10 billion gallons of it each year.

Fortunately, air conditioners are not the only. way to stay cool. After all, humans existed a long time before AC, and we came up with some very clever ways to keep buildings cold. Things we might take for granted now. Like just courtyards. They provide both lots of cross ventilation and shading. Or kind of a similar concept, the Dog Trot House. Used to be pretty common in Appalachia. Basically a house with a big hole right down the middle that let air pass through. Or in truly extreme heat, there's just a little. living underground. The world had been through a trial by fire.

You might recognize Cuber P.D. from post-apocalyptic movies like Mad Max Beyond Thunderdome, if you caught that. It's a mining town in the Australian Outback. It's famous for its underground motels, churches, and homes. And yeah, it kind of looks like the end of civilization. But living underground, it does keep you cool. So we've got living underground, courtyards, dog-trot houses. but best of all is the centuries-old technique of beaming your heat into space.

It was mostly in Iran, as far as we can tell, about three to 500 years ago. Ashwat Rahman is a professor of material science and engineering at UCLA, and a co-founder of sky-cool systems. And he says, in Iran's ice houses, these places where they made and stored ice, they took advantage of a strange phenomenon. So basically they had a thin, flat, pool of water. And they would be doing this in the winter, so it's not super warm to begin with. But even though the air temperature almost never got to freezing, that thin sheet of water,

if it was exposed to the sky sufficiently, it would freeze overnight. That's because of radiative cooling. It's actually something that all materials do naturally. It's a basic property of nature that if you're at a particular temperature, you as a material will emit or radiate heat away. And the wavelength, at which you radiate that heat away will depend on your temperature. So that's what you see on night vision cameras, all the infrared radiating off of things. The hotter they are, the brighter they glow.

And what happens when you put something out on a very clear night is it can radiate out so much heat that it actually cools down, maybe even freezes. So nine years ago, Ashwatt was a PhD student when he learned about this. I was very curious about this because it sounded pretty amazing. It's passive cooling that you don't need to do anything. All you need to do is have something outside exposed to the sky and it cools down. It's almost too good to be true.

So it was very perplexing. Why hadn't this been developed further? Why weren't we using this everywhere? One of the problems was that this effect was only happening at night. Because during the day, yes, you are still emitting heat as infrared, but it's totally canceled out by all the heat you're getting from the sun and your surroundings. So when we began working on it, we asked, well, can we enable this effect during the daytime as well? And if we could enable it during the day, that would be potentially extremely exciting because then you could achieve the same kind of passive cooling effect, but during the hottest hours of the day when we need air conditioners and refrigerators the most.

What Ashwath and his team ended up developing was a little more sophisticated than a pool of water, something that was really good at cooling down and basically counteracting the whole greenhouse gas. gas effect. So greenhouse gases. Think of them as a big invisible blanket over our planet. We send out heat as infrared radiation. Our blanket catches it, sends it back down, keeps us nice and snug, sometimes a little too snug. But the blanket doesn't catch everything. So if you emit heat at just the right frequencies of infrared, it can blow right past the blanket and into space. So Ashwath and his team designed these films down to their nanostructure so that they were very good at two things. First, they were really good mirrors.

They were really good at reflecting away sunlight. And second, they radiated their heat away at very particular frequencies of infrared radiation, frequencies that could slip right past the greenhouse gases. And it worked. Like, usually, if you put something out in the sun, it gets hotter, right? But Ashwatt's material, it got colder. So it's really counterintuitive. And the first few times I would just touch it, just to check that it was actually working,

which of course ruins the experiment because you have to start it all over. So if you think about this, it solves a major problem that air conditioners have. Instead of dumping the heat outside, making your surroundings hotter, you send it to space, technically cooling down the earth ever so slightly. And Ashwat's not the only one working on this kind of thing. You might have seen recent news about super white paint. So instead of a film, it's actually a paint, and you could paint it on, say, rooftops to cool them down.

All of this gives me these nightmarish sci-fi visions where we install these materials everywhere and accidentally freeze the planet. I mean, people have very slatedly talked about putting mirrors out in space. You know, if you put it far enough away and it's substantially large, it can actually create a bit of a shadow. It's like the Simpsons episode, Mr. Burns does that. But we're obviously nowhere near that.

And right now, Ashwet's company Sky Cool, they're not even trying to replace air conditioning. They're actually using these materials to cool down air conditioners, so they don't have to work quite so hard. Everyone I spoke to was emphatic that we will absolutely need air conditioning, no matter what, especially as the climate warms. But if we're strategic about it, if we combine reflective materials with the basics, like more tree cover, designing buildings that shade themselves and naturally ventilate, then maybe, even though we'll still use air conditioning, we'll need a whole lot less. The old saying, everybody talks about the weather, but nobody does anything about it, is not quite true. Heating and air conditioning engineers have done plenty about the weather. The National Academy of Sciences lists air conditioning as one of the ten greatest engineering achievements of the 20th century.

And it's true. Our world would be unrecognizable without it. It's the big things, the skyscrapers, the movie theaters, the data centers. Think about computers without air conditioning. But it's also that little drip on your head out of nowhere on a clear sunny day, or that ongoing battle with your office mates about whether it's too cold or too hot, and whether anything under 70 Fahrenheit is a sexist temperature. And it's also the humph.

and the rattle of your ancient window unit that's lulling you to sleep on a hot summer night. In August, a period of intense heat gripped the city of St. Louis. Temperatures shot way up all the way to the mid to upper 90s. We were all ants under a magnifying glass, running from our air-conditioned cars to our homes. But then one Wednesday. So I just came outside and I'm standing on my porch. in South St. Louis and it is an absolute downpour out here. I actually have to move because I'm starting to get a little wet. Just constant lightning and thunder and cicadas screaming. This is kind of our

summertime soundtrack here. We'll get these, there you go. We'll just get these kind of incredible downpours in this city when the heat breaks. We'll have really really hot days and then suddenly the sky just opens up, and that's what's happening right now. We had a couple days of relief after that storm. We could come out of hiding, walk around outside again. And then, less than two weeks later, the heat was back, worse than before. Because for all of our tricks and technologies, our refrigerants and pumps and compressors, all we're really doing is buffering ourselves from the outside world, giving ourselves a

little bit of relief until nature decides to give us a break. Air conditioning. It provides comfort. It saved countless people. But at the end of the day, it's weather that rules our lives. This story was a collaboration of Science Friday and St. Louis Public Radio. It was produced by me, Ella Fetter. And me, Shayla Farsan. With production help from me, Johanna Mayer. All of our music and sound design is by... Me, Daniel Petersman. We had research and fact-checking help from me, Lauren Young, and Charles Berquist was the voice of refrigeration engineers from 1904. Special thanks to Andrew Aline for explaining to us how air conditioners work, and to Salman Craig and Komalianity for talking to us about cool building and city design,

and to historian Adam Kloppy, who taught us all about the 1904 World's Fair. If you want to learn more about air conditioners, we had a great time reading Salvatore Basel's book, cool how air conditioning changed everything. We also found Gail Cooper's Air Conditioning America very illuminating. We've got more information and links up at ScienceFriday.com slash AC. After the break, discovering a group of brain cells that seem tuned to recognizing familiar faces. Is there a grandmother neuron? Stay with us. This is Science Friday. I'm Ira Flato. What happens in your brain when you see a familiar face? You know, you hear the door open, your face lights up when in walks grandma, whom you recognize immediately.

Scientists have wondered for years, how come your brain reacts so immediately to Granny's familiar face? Is there a so-called grandma cell in your brain that is programmed for immediate recognition? Well, maybe not one neuron, but perhaps a whole bunch. Researchers recently reported in the journal Science that there may be a specific, group of neural cells that are tuned to respond to the sight of familiar faces, at least in monkeys. So what does that tell us about how the brain is organized? Joining me now are two of the scientists working on that research, Dr. Sophia Landy, now is Schmidt Science Fellow at the University of Washington. Welcome to Science Friday. Thank you so much for having us here. You're welcome.

And Dr. Vin McFriwall, Professor of Neurosciences and Behavior at Rockefeller University. Welcome to you, too. Thank you so much. You're welcome. So Dr. Landy, can you walk us through this discovery? You looked at how monkeys respond to images of faces, and then what? Yes. So we examined an area in the brain that is the temporal pole, and it's an area that is

poorly understood, so we don't know much about it. And it's an area that is located right below your cheeks, more or less at the bottom of your brain. And we had identified this area before as one of, two areas. that might be involved in familiar face recognition in a study that we published a few years ago. So we used for this study functional magnetic resonance imaging to scan the brains of monkeys while they were looking at images of faces in a screen. And these brain scans served us as a guide so we can, in a way, zoom in and record the activity

of single cells or neurons in the brain. Dr. Frywald, would this area be the same kind of area that humans have? We actually just got data on exactly that. And yes, we believe that there is the same area also in the human brain as the monkey brain. Tell us a bit more about that part of the brain. As Sophia mentioned, it's a mysterious part of the brain that we don't know very much about. And it's largely because it is very difficult to obtain any signals from. And we believe that that is part of the reason why,

the question that you post in your introduction, are there grandmother neurons, what happens in your brain when you see the face of someone you know very well, that this question has remained unanswered for decades. So we now think that this region might be a very critical hub that is linking visual perception, the perception of a face, to memory and knowledge of people, and maybe even more broadly to, you know, other familiar things as well. And within this larger brain region, there is this sub-region that you also mentioned in your introduction that appears to be entirely specialized on faces. So linking the perception of a face to your memory or knowledge of people. But we see so many people that we know in real life that we would recognize immediately.

That means there's got to be a whole bunch of cells in there for all these different people. Does it not, Sophia? Yes. So actually, what we found is that some of these cells are very specific to one individual and other cells, they get activated when you look at pictures of, let's say, all your friends, for example. There is the sense, Ira, when you recognize someone, it's not just in an automatic process or a thought process. It almost has an emotional quality to it. You know, you mentioned, you know, when you recognize someone or even anticipate seeing someone, and, you know, that you might feel happy in anticipation or recognition. And so there's the sense of familiarity that you get. And so we think that these neurons that respond to all familiar individuals might be eliciting this process, this feeling of familiarity.

And could this process be happening not just with facial recognition? What about smells and sounds and things like that? Yes, that's actually also another good question. We looked into voices, for example, if voices could elicit a response in these neurons, and the answer was no. But we believe that nearby regions might be doing the same process with other stimuli that are not visual stimuli, such as voices, that would allow you to recognize someone in the same way. Why would the brain have this type of cell? What would, what's the reasoning? What's the point? Well, you know, we're very social. animals, all primates are, and we depend on others to survive. So our brains evolve in order to

support that very basic social function of identifying who we see, how we react to different individuals. Once you identify who you're seeing, you will not react in the same way if you see your grandmother or if you see a friend, right? So you have to adapt your behavior to who you encounter. It's very important. We began talking about the theory that scientists have had about a grandma cell. And now we're talking about grandma cells, in plural. Do we know how many, approximately how many cells it takes to make this recognition? We would estimate maybe a million.

It's maybe more in humans. The initial idea actually was that there was going to be 18,000 cells. It was a made-up story by an MIT professor at the end. end of the 60 Jerry Latvin, but it soon became, was transformed into this idea that there's one cell and one cell only for every individual that you know very well. So there will be one cell for one of your grandmothers, a different cell for a different grandmother of yours. What Sophia discovered is that there's a whole population for each individual that you know. and that the different populations, that the populations that are active for different people can

actually overlap. That's really interesting because I'm wondering, do these cells store the memory of the face itself or, as you say, interact with other parts of the brain, somehow check in with the memory part of the brain to accomplish that recognition task? So we believe this is happening. We have not demonstrated this. We would love to demonstrate that. what we were surprised by is that these cells are so specific to phases only. It is very clear that

they form a link between the perception of a face and your knowledge of people in general, but this link is formed by these neurons only for the perception of the face, not the body, not the voice, nothing else that we tested. And to us, it was really surprising, you know, why this mechanism would exist and would have this specificity. Sophia, do we know what it is about the face that they're keying in on that makes it specific to just recognizing the face? So we know that these neurons like the inner part of the face, so they don't care as much about the hair line, for example. And we also know that if you attach the face to like the whole body of the individual, these cells respond even in a stronger way.

That's all we know now. Like this is, this. studies really like the starting point to answer a lot of the questions that you have, actually. I would imagine there's a lot of questions you'd like to answer for this. I mean, one that comes to mind for me as well. Does it matter if the face is smiling or not? Sophia actually tested this. We think that these cells are largely independent of expressions, of emotions, and that they're capable of responding to faces as seen from different viewpoints, is seen different distances and with different facial expressions. Now, I understand from your research that the monkey neurons only responded to other monkeys that they had seen in real life.

And when you show them pictures of those monkeys on the screen, only those monkeys they had seen in real life they responded to. Would that be correct? Yes, that is correct. But, you know, I'm asking because for we humans, we've got famous people all over the place that we probably want to recognize even though we haven't met them personally. But we've seen them on TV or movies. Might we perhaps respond a little bit differently because we've never met these people? Yes, I think that that's a very interesting question. And it also ties with a lot of studies that are done in patients when some conditions need to be diagnosed, a lot of face name recognition tests

that are widely used in, for example, Alzheimer's research. They tend to use famous faces, as proxies for familiar ones. So if what we see in monkeys is also true with humans, we might be missing some dysfunction of this area if we don't use personally familiar faces in these tests. So something that we still need to study is how many times we must see a phase and in what context before these fast-responding temporal-pore neurons

are able to encode it. So this is one of the many questions that we yet have to answer. In other words, how familiar do you have to become with that face over and over again? Exactly, yes. It's very interesting to think about what it is that happens when we acquire familiarity with a person. Isn't it that when we see the picture of a famous person that we have a bit of a sense of familiarity? So for us humans, it might be that indeed the face of a famous person might appear at least partially like that of a familiar person. Obviously, we're not personally familiar with them, but it appears to us over exposure, reading about this person and so on and so forth.

So one of the things we would like to figure out going forward is, you know, what actually is it exactly? that is generating the sense in us and in our brain that we are familiar with another person. Could it be that it's evoking a memory of our interaction with that person, you know, either a nice, warm one or one that's not so nice, but we feel it in other parts of our brain? That's exactly what we think. But the interesting thing about famous people that we've never met is, you know, how would that happen if we never had a personal encounter with them?

yet to some extent they appear to be very similar to familiar people. Now, how do you apply this to people? I mean, is it possible to directly measure this in people? I know in monkeys you had to put electrodes in their heads. You really can't do that with people, can you, Vinrik? We cannot. That is the reason why we are working with monkeys, the fact that they are similar to us,

and the fact that we can record activity in the brain. With fMRI with brain imaging, we can answer the question, where is something happening in the brain? And we talked about the importance of that before, because we had no idea what was happening in the brain because we didn't know where to look. But after the brain imaging, we know where to look, and that is allowing us to figure out how things work,

like what is really happening, what are the computations that are going on, that is not possible to do with brain imaging. So we like to do both studies. We like to know what is happening in the human brain. we would like to illuminate the human condition, but these mechanistic studies require the monkey model. You know, smells, odors evoke such strong emotions.

Might you find also a separate area in the brain that might be devoted to odors and familiar smells? Odors and familiar smells are probably a different process. They evoke such strong memories, you know, of your childhood and early experiences, and they're very strong links in all kinds of mammals, mice and humans alike, that mediate these processes. They likely use very different routes and very different mechanisms.

This very specific familiarity with individuals is something that requires a very high degree of sociality and of social intelligence, really being able to differentiate between individuals and a social group. This is Science Friday from WNYC Studio. Sophia, I know that you've moved on from this project, but are you still studying memory? Yes, I'm trying to. Yes. I'm trying to study a different structure in the brain that is called the hippocampus that has been hypothesized to be involved in episodic memories.

So, for example, what you were describing about, like, having an odor that elicits a very rich experience from your childhood. how does the brain enable a process like this? Dr. Freibald, does this finding teach us anything about memory in general? We think so. There is a very specific organization here, and we discovered this organization by focusing on phases, but we believe that it's recapitulated for other socially important stimuli. We have an amazingly rich, an amazingly sophisticated,

structure of social knowledge. We don't just know individuals. We also know their relationships. And these are very sophisticated data structures, if you will, and we believe that they reside in the same brain region. The second answer to your question would also be an answer to you earlier question about the organization of brain systems. We believe that this finding shows that there may be two different pathways of memories that we've not appreciated before, that there's one pathway to form the memories and another pathway to retrieve them. The reason we believe that is that these cells are responding with astonishing speed. We had imagined that it would take them longer to respond, longer to respond than cells we discovered before that respond to all kinds

of faces, familiar and unfamiliar ones alike. But it turns out that these cells that respond specifically to familiar individuals are responding just as fast as the other cells. So there must be activated by a separate pathway that we don't know yet. Sure, because when somebody walks into a room as a surprise and you'll immediately recognize them, don't you? Exactly. So maybe we should have expected this, but we did not. Doesn't all this sort of tell us that we really don't know

how much about the brain as we think we do? I mean, it just seems so fascinating. Something as common as this is just being discovered. I think if you're in neuroscience, I don't know, Sophia, if this is your sense as well. I've been around now for, you know, some 30 years. And in our line of work, I think we do appreciate how much we don't know yet. On the one side, we know a lot.

You know, there's a gazillion facts. There's so much published all the time that it's impossible for anyone to keep track of everything that's discovered. And there's probably no other organ in the body that we have a similar amount of knowledge amassed over time as we have for the brain. yet to explain, especially cognitive phenomena, you know, the question to answer, like, what makes us intelligent, I think we do appreciate that, you know, there's a lot that we still don't know. Fascinating. Thank you both. We've run out of time. Dr. Sophia Landy, Schmidt Science Fellow at the University of Washington, and Dr. Vinrich Fryvald, professor of Neurosciences and Behavior at Rockefeller University. Thanks again for talking with us today.

Thank you for having us. Thank you so much. One last thing before we go. Our fall book club is reading about sea level rise, coastal wetlands and people living on the front lines of climate change. In Elizabeth Rush's book, Rising, Dispatches from the New American Shore. We'd love to hear from you if you're reading along. Tell us your thoughts on the sci-fi vox pop app. Any questions, feelings, observations, something from your own life that comes up as you're reading.

Tell us about it. That's on the SciFri Voxpop app wherever you get your apps. And of course, if you missed any part of this program, you'd like to hear it again. Subscribe to our podcasts or ask your smart speakers to play Science Friday. And of course, we're active all week on social media, Facebook, Twitter, Instagram. Or you can email us, the address, SciFri at ScienceFriaday.com. Have a great weekend. We'll see you next week.

I'm Ira Flato.