Science Friday - Smell Science, Reader Come Home, Sonar Smackdown. Nov 16, 2018, Part 2

Episode Date: November 16, 2018

If you had to give up one of your senses, which would you pick? If you think that “smell” might be the obvious answer, consider that your nose plays a crucial role in how you perceive the taste of your food or that it’s a sophisticated sensor capable of synthesizing the hundreds of different molecules into the floral fragrance we know as “roses.”  University of Florida professor Steven Munger explains the nuances of smell. Plus: The digital world is changing how we read. What does that mean for the next generation of readers? As Maryanne Wolf describes in her newest book, Reader, Come Home, we may be at risk of raising a generation of people who don't have those skills simply because of our changing reading habits. She joins Ira to discuss how our reading brain has changed since moving into the digital world and what we can do to fall in love with reading again. Are you team bat? Or team dolphin? Earlier this month at the Acoustical Society of America Conference two groups of scientists argued the finer points of each animal’s echolocation excellence. Things got heated, words were exchanged. But in this battle between the sonar specialists, which creature comes out the winner? To settle the debate, two researchers join Ira for a good, old-fashioned “rumble on the radio.” Laura Kloepper, assistant professor at St. Mary’s College backs up the agile, winged masters of the sky, while Brian Branstetter, research scientist at the National Marine Mammal Foundation in San Diego, vouches for the swift swimmers of the sea. Both are ready for Science Friday’s first ever “Sonar Smackdown.” 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 Ira Flato, broadcasting today from the studios of WUSF at the University of South Florida in Tampa. A bit later in the hour how digital reading is changing the way our brains work. But first, autumn leaves, burning wood smoke, onions sauteed in butter, or mom's rice and beans, hamburgers sizzling on the grill. You hungry yet? Well, we asked our listeners on Twitter for their favorite smells. And these were just a few, along with rose geranium, new car smell, or a new baby. Now, think about life without those smells, without any smells at all. It's a lot dimmer, right? Even isolating.

And my next guest says that there's a good reason. The smells are perhaps one of our more underrated senses, but it's one that rules the social lives and behaviors of many animals. rodents learn what's safe to eat from sniffing each other's saliva. Dogs follow scent trails, and even we humans, we can detect odors better than we think we can. Dr. Stephen Munger is Professor of Pharmacology and Therapeutics and Director of the Center for Smell and Taste at the University of Florida in Gainesville. Welcome to Science Friday. Hi, I, Your Honor. Thanks for having me, and welcome to Florida. Oh, thank you.

You know, I think people think that the sense of smell is very mysterious. how it works. So give us a little bit of an ABCs of what's happening in the nose when they smell and odor. Yeah, I think with smell, it's a little more abstract for people, but really it's smell along with taste and also what we call chemistesis, which is the ability to detect some of the chemicals and things like spices. These are collectively called the chemical senses. And in olfaction, the sense of smell, we're sensing chemicals that are generally volatile and are wafts. through the air and we inhale those when we're sniffing or they come from our mouths up through our pharynx into the back of our nose when we're chewing food or drinking a drink.

And those odor, those chemicals interact with neurons, sensory nerve cells within the nose that then carry that information back to the brain. And in most cases, it's certainly for humans. We get a pattern of neural activity that we relate to something in our experience. and it tells us that we have a tangerine or we have a rotting fish or whatever it might be. But in mice brains, you found something extra going on, a whole different level, right, of processing smells that's socially informed. It's right.

People might be familiar worth the term pheromone, which a lot of animals use, and these are a type of a social odor that one animal will convey to another and that often elicits a very stereotyped or very innate response. What we found was something slightly different than that, and it's a dedicated, olfactory communication between two individuals, but it allows them to learn something about each other and about their environment, and particularly this is something that's been termed the social transmission of food preference. It was when one animal maybe is out in the wild and eat something, and he, and

it's not bad for him, he doesn't die, interacts with one of his compatriots, and they sit there and they sniff each other. The second animal will pick up both the social odor and the smell of the food that their friend ate, and that will be associated in their brain and a preference will be formed. And so the next time that that second animal encounters potentially that food in the environment, they will say, okay, someone else I knew ate that food. It seemed to be okay for them. This might be safe to eat as well. So it's a learned thing. Don't we people have that kind of association, maybe not exactly the same way, but...

We do have that kind of association in a couple ways. One thing we do is that we have substituted for that kind of communication. In some ways, we've substituted language, tone of voice, facial expressions. If you and I were to go to have dinner this evening and each got a couple different dishes and you would say, oh, this is wonderful, you should really try it. Or I say, oh, this is horrible, stay away from it. We're able to convey that type of information. In a nonverbal animal like a mouse, they have allowed, they use odors in part of that way to do.

But certainly we use odors to communicate between ourselves in more subtle ways. You mentioned the smell of a baby. That's a key way for a parent and a child to bond through odors in that way. And we also say that, you know, we're good at recalling odors. didn't remember we knew, right, from 10, 20, 30 years ago? Yeah, and I can't say that we know for sure exactly why that is. There seem to be particularly tight connections between the areas of the brain that process odors and the areas that deal with memories and deal with learning.

And this sort of makes sense. As I mentioned, we aren't born knowing what a pizza smells like or that something that smells like pizza is pizza or that it is cilantro or whatever it might be. Those are associations that we learn over time through our experiences. So having the detection of an odor and the pattern and activity it initiates in the brain be so tightly linked to learning in memory makes a lot of sense. Now, we're always brought up thinking that, you know, a dog's smell or ability to track an odor is so much better than people. I mean, how does the human sense of smell

compared to, say, a dog or a mouse? So a lot of it depends on how you define better or worse. I mentioned before this idea of pharma, and certainly dogs like to sniff different aspects of other dogs and what they've left behind, different body parts and get signals that way. We don't seem to have those types of capabilities as humans. but if we were just to talk about our sensitivity to general odors in the environment,

we are actually remarkably similar. And there was a study done probably about 10, 12 years ago now, where this one laboratory, and allowed on the graduate students to do this, actually had humans following a scent trail on the ground, and they were able to do it fairly well. So we have actually a remarkably good sense of smell, but we maybe don't use it in as many different ways as some other animals like a dog might do. That's it. So we do have a powerful sense. You also work on treating smell disorders. What are those,

and how common are they? They are actually surprisingly common. The estimations can vary depending on the age. If we were to look at the elderly, the majority of people over about the age of 75 have a significant impairment in their sense of smell. If we were to look at a broader population in the U.S., probably about 30 million people have a significant smell impairment. And there are different types. There are what we call anosmia, which is the complete absence of smell. Hypoasmia is lowered smell. Parasmia is distorted smell, where you smell a flower and it smells like burning rubber. And people even have smell phantoms where there's no odor there, but you think that there is. And these, not only affect what we might think immediately the way we perceive our food and drink

and the decisions we make about what we might want to eat, because the smell contributes so much to the flavor perception of our food, but it really connects us to our environment. And the people who have an absence of a sense of smell often report that they feel isolated from each other, and they feel isolated from their environment. and certainly they don't have that same picture of the world. We just had a conference is where I'm flying back from right now. In Philadelphia, where our Center for Smell and Taste, collaborating with two other research centers from around the country,

put together a conference to try to investigate the best new strategies for developing therapies for individuals with smell disorders, and that meeting included patients. So we were able to hear from them, their concerns, and what would be most valuable to them. If you have a smell disorder, is it something that originates in your nose sensors being faulty or something in the brain?

They could be either. So smell disorders, if we just think about the most straightforward one, a nosmia, the absence of a sense of smell, that can result from head trauma that could damage either the brain or the smell nerve, the olfactory nerve, that is going from the nose to the brain. people can lose their sense of smell after inhaling toxins, like in some industrial context.

Some can lose their sense of smell after having really bad cold if those cells are damaged. But there are also congenital smell absence where people are born because of a genetic mutation or something else. So there are a variety of causes and it can be peripheral or in the central nervous system. You know, we always hear that if you have a cold or you can't smell it, it really affects how. you taste food also. How much of the flavor of food comes from my tongue, how much comes from my nose? Yeah, you typically hear the number, 80% of flavor is smell, and that number maybe is a little arbitrary, but certainly a vast majority of what you think of as what most people would

describe is the taste of food really is the smell of food, and it's the smells, the odors that are coming from the food in your mouth going back. up through your pharynx to your nose. If you've, you know, you're drinking, remember as a kid, you're drinking a glass of milk and someone tells a joke and the milk comes out your, comes out your nose. It's because it's all connected. And those odors are, if you don't have that, you're really restricted to sweet, salty, bitter, sour, and amami, the savory taste.

Can people lose their smell and regain it later in life? Something happens? It does happen, particularly for people who have lost it due to a viral infection, that the recovery is more common. It's not always the case, and a lot of people never recover. But those who have lost because of a head trauma, it's much rarer. And then certainly those who are born without it, it would be very uncommon. And what would you as a scientist like to know more about smell? What's your burning question?

Oh, there's a lot. I think one of the things that we discussed at this conference that sets smell and taste apart from some of the other senses is just the, our understanding of how to measure the loss. You asked about, does it happen in the nose? Does it happen in the brain? If a patient comes into our clinic and describes the smell loss, we oftentimes, unless you can visibly see damage, with something like an MRI or through an endoscopy exam, you don't know. And if you don't know what has physically gone wrong or genetically gone wrong, it's hard to correct the problem. All right. We've run out of time. I see where you're going with that. Dr. Stephen Munger, Director of the Center for Smell and Taste the University of Florida

in Gainesville. Thank you very much for taking time to be with us today. Fascinating. Thank you. Have good day. You too. We're going to take a break on when we come back of what neuroscience tells us about the reading brain in a digital age is what you read on your tablet different than how you read and what it

does to your brain in a real book. We'll talk about it. It's interesting work after the break. Stay with us. This is Science Friday. I'm Irafito. Has this ever happened to you? You return to a book you used to love reading and suddenly it's, well, it's lost its magic. The writing is complicated. The prose is dense. It just can't get through it. So what's going on here? Have you fallen out of love with Proust? More likely it's your reading brain that's changed. Your reading brain, these days we've experienced more of what we read online, and that has made us excellent skimmers and multitaskers,

and maybe Prost is not really a cup of tea anymore. But according to my next guest, not so good had a kind of reading that requires critical thinking and analysis, even considering other people's point of view. That's what happens when we, you know, reading online. My next guest says we're at risk. of raising a generation of people who don't have those skills simply because of how we read. So I ask you, do you notice a difference in your reading style when you read something online versus in print?

Give us a call. Our number, 844-724-8255-8-4-Sy-Talk or tweet us at SciFry. Marion Wolf is the director of the Center for Dyslexia, Diverse Learners, and Social Justice at UCLA. She is author of the new book Reader Come Home. Welcome to Science Friday. It's my pleasure, I know. You've long been a hero of mine. Have you fallen out of love with Proust?

I mean, you know. Not at all, but I've had to recover it, so I'm a recovering Proust reader. What do you mean you've had to recover? Tell me about that. You write in your book that you've had this experience, happens to you where you return to a book, you've loved many years late and you couldn't read it anymore. Yes, I have written a series of letters in this new book,

and in Letter 4, I acknowledge one of the more humbling experiences in my scientific life in which I made myself the single subject. And what happened was I decided, since I'm telling so many people about how their brain is changing when they read, I thought I would simply look at myself. And that was the beginning of a rather terrible experience. I picked up Herman Hesse's Glass Bead game, which once was one of my most favorite pieces of literature. And Ira, I simply couldn't read it. It truly felt like I was pouring molasses over my cerebrum, and it was so humiliating.

I thrust the book back until I realized Herman Hesse, all these people have been the friends of a lifetime. They have made me who I am. And so I determined to go back and read, but very differently, just read 20 minutes a day. And Ira, it took 10 days for me to return to that mode of reading in which I could immerse myself. and not be distracted by syntactic density or length or even the complexity of the arguments there. But it took a good 10 days to return home, if you will. And you attribute that to the fact that you were doing more reading online versus reading in a book? I mean, that's sort of one of the thesis of your book.

Yes. We are wrecking our reading habits and wrecking a lot of other stuff because we're reading online now instead of reading from a paper. Well, it begins with a statement. And it's very important that your listeners and my readers understand that I'm not making a binary argument. I am saying, however, that because the reading brain is plastic, you know, we never were meant to read. We had to form this beautiful new circuit. But because it's plastic, it reflects things like the writing system. A Chinese reader is different from an English alphabet reader, but it also reflects the medium.

So the dominant medium is going to be reflected in the style of reading, even when you're not reading on the screen. It will affect you as you read print. And there are good reasons for that. Quite literally, our circuit is, it's like a mirror held to the processes needed by any medium. So if a print medium is giving us precious, though imperceptible time to allocate milliseconds to inference, the scientific method processes, critical analysis, immersion, that's the advantage of print that's the advantage of print that. we think will be just continuous no matter how we read elsewhere, but it's not the case. The advantages of the screen, which are hastening us along, multitasking, being ready for the next novel experience, that ends up making us skimmers. And skimmers literally skimms what I call the deep reading

processes that involve critical analysis and empathy and even insight. And you say all those, that whole idea about skimming and because we're not doing critical analysis and insight, you say that's actually a threat to democracy. It was the last thing in the world that as a cognitive neuroscientist, I would be thinking I'm actually confronting implications for democracy. But the reality is that, that one of the most precious aspects of deep reading is that we give time to inference, we give time to critically analyze and evaluate

the truth of what we're reading. And also, and this is often neglected in understanding reading, reading gives us an opportunity to engage our feelings of empathy and also our engagement with alternative viewpoints. And one of the things that I will never forget was an interview between former president Barack Obama and the beautiful novelist Marilyn Robinson about the power of reading to give empathy. And Obama said, the novel is what has taught me moral and ethical development. It taught me about other, to which Marilyn Robinson said, the trend towards seeing others.

as sinister others is one of the greatest threats to our democracy. And I'll end this little part of our discussion, Ira, with a quote from Jane Smiley or a paraphrase in which she was asked about the novel and empathy, and she said the novel's not going to die, but it may be sidelined. And if it is sidelined, we will be led by people who do not read,

who do not understand fully the feelings and the minds of others leading us to a potential new era of barbarism. So when you say reading online, you are making a distinction between reading websites, things, places like that, and reading a book that might be a Kindle or an e-book or something like that, correct? You know, this is a really important distinction, Ira. there are different modes of reading, and we need to understand that even the Kindle, which is far better than reading in a distracted Internet-type computer environment or screen environment, even though that's far better,

you still have three problems. You have a set towards the screen, which is the set or anticipation of evanescence, of transitory images. So you end up still having, this set towards speed, hastening along. And in addition, the second and third parts are you don't have that concrete kinesthetic element that actually is activated in your brain and slows you down to allocate more time to these other processes.

And you do not ever have what is called recursion. You can't return to monitor what might not have made sense. a few minutes ago. In a screen, even in a Kindle, even though it is possible to return, you do not. Therefore, your comprehension monitoring on a screen, while far better than a computer,

actually has some of that transitory, imagistic element that makes you speed faster than you would in a print form. A lot of folks want to comment on this. Let me see if I can get a call or two in. Let's go to Andrew in Cleveland. Hi, Andrew. Hi.

Wow, it's one of those moments where I'm listening in the radio, and I now have more questions that I came in with. But I work in a variety of schools all over Northeast Ohio as a substitute teacher, and I'm often seeing students who, the one thing they lament, is, especially at the high school level, is reading their literature assignments. And admittedly, some of those books are harder to get through. I'm a big advocate with them for using audio books. books as a means of, you know, getting their material covered.

And I'm curious as to your guests, see that as another step down the slippery slope, or if having a human voice reading to you is a step in the positive direction. And while I was listening, I was curious, do we know if, is there any data on students that are taking tests by a computer as opposed to tests on paper? and they're reading and retention of those questions, and is there any indication that the one is better than the other or more harmful? Right, Andrew, thanks for that. What about being read, too, like, in those?

Right. This is a beautiful question that I'm often asked, and I liken in many of our young as not necessarily deep readers, but deep listeners. And I think it's a wonderful aspect, because we're getting so much information that they might not read. And so I consider it a good but still insufficient alternative for the same reasons that involve comprehension monitoring on any screen. And that is, with the audio, again,

though you can go back to check yourself, to monitor your comprehension, to remember the details, you don't do it as easily, or it's very unlikely that you do it. So even though I consider this as a positive, I don't consider it a replacement. And indeed, your listen to the teacher couldn't be more correct.

So many of our professors of high school and college are lamenting that their students are no longer willing or have the cognitive patience to read long-form text. And there's this common little, Aforism, T-L-D-R, too long, didn't read. And the reality is that our professors are so worried that our students are really neglecting some of the 19th century Melville or 20th century James. There are people who are writing me often in saying they are no longer having people coming to their seminars because of the density and lengths of books are often. are off-putting and their students don't have what I'm calling the cognitive patients to invest

in retraining themselves to be able to read that. And there are implications not just for literature, but for referenda, for contracts, for dealing with the complexity of worlds that can't be reduced to Twitter or Twitter brains. You know, we don't want that for our young. Can you offer any remedy for this trend? Well, I certainly have been thinking a great deal about what would it take to develop deep reading skills across every medium? Because that's really what we're talking about. It's cognitive choice to preserve what we know we want our next generation to have.

At the same time, not just allowing but propelling them to expand their 24. first century skills, their visual intelligence that goes so much beyond ours. So we want both. And here's where I tell your listeners, and it's the perfect show in the world to say this. It is a hinge moment in which knowledge from science needs to be yoked with the designs from technology to be able to redress this and to create children who are really capable of by, and by digital brains that have equal skills. Now, you may know this in Ira and your readers wouldn't, your listeners wouldn't, but I have proposed a way in which our children move from zero to ten on print

and carefully use that kind of sensory motor, concrete kind of cognitive skills of children to learn deep reading over time with print. And then have our teachers, explicitly trained to teach deep reading skills on the screen so that it's not this willy-nilly assumption that you read the same on each mode, but rather students are trained to ask what is the purpose? What am I better at? Students don't know what they're better at.

I better get a break in here. This is Science Friday from WNYC Studios. I'm sorry we have to I know Ira this is so funny but but it's an interesting point so you're saying that we could have it you know a dual bilateral brain is as you call it you could teach them how to read in print and then morph them over move them over and to take the same skills with them when they read online absolutely and that's what you're saying yes yeah but simultaneously I want them developing of at least least from five years on, the coding and programming skills, these are essential. And they give some of the same deep reading cognitive skills that comes from print reading. I want those to come together. It's not either or. But you would have to retrain teachers to know how to do this, correct? Yes, yes. And there's really wonderful work in Europe and Israel and the beginnings here

that we must have our teachers literally learn how to use the best of technology and the best of print. And we really need a whole generation of fresh professional development on this. Can parents do anything while they wait for the teachers? Oh, yes. Oh, yes. And parents have to actually be a good part of the story because it begins at zero and zero to two when a lot of parents. are believing that the bells and whistles are good for their kids when they're, in fact, not as good as they are in enriching language development. So before two, I want very little screen time for the kids and never use it as a pacifier, the iPad as pacifier or as a caretaker, but to use it mindfully. Catherine Steiner-Dare is a clinical psychologist who talks a lot about how we need to think.

think about guidelines. Oh, also the American Academy of Pediatricians, Barry Zuckerman, all of these people are really telling us how important it is to read and talk to our children in zero to five with only a gradual use of digital technology during that time. You can read more about this in Marianne Wills' really interesting book. Reader Come Home. You can check out an excerpt of her book on our website, Science Friday.com slash Reader. Thank you, Marianne, for taking time. It's fascinating conversation.

Good luck to you. Absolutely for me. Thank you, Ira. We're going to take a break when we come back. It's Team Bat versus Team Dolphin in a battle for Sonar superiority. Which one do you like better? Bat or Dolphin. We'll have a Smackdown after the break.

Stay with us. This is Science Friday. I'm Ira Plato. So are you Team Bat or Team Dolphin? Of course, you don't know what I'm talking about. yet? Here's the deal. One mammal uses sonar to navigate complex spatial environments through the air, right, like a bat, while the other uses underwater sonar to find fish hidden beneath the sand, like the dolphin. But whose sonar is superior? That or dolphin? Well, earlier this month at the

Acoustical Society of America conference, two groups of scientists argued the finer points of each one's echolocation excellence, one-sided with Team Dolphin, one-sided with Team Bat. Things got pretty heated. Words were exchanged. And so we thought we know how to settle this with a good old-fashioned rumble on the radio. And so I bring you Science Friday's Sonar Smackdown. In this corner representing Team Dolphin, we have Brian Branstetter. He's a research scientist with the National Marine Mammal Foundation in San Diego. Welcome to Science Friday. Hi, thanks.

Glad to be here. This corner representing team bat, we have Laura Klepper, assistant professor at St. Mary's College in South Bend. Welcome back to Science Friday, Dr. Clepper. Oh, thank you very much for having me, Ira. You're welcome. And we want to, if you're listening, we want you to let us know on Twitter if you're our team bat or team dolphin, tweet us at Cy Fri.

And we'll try to keep score. So before we begin, I want to give everybody a sample of the kinds of team sounds that we're talking about. I'm going to start off with Team Bat. We're going to play a little segment of what a bat sounds like. The kind of sounds, a bat sounds like this. Very, very interesting. Okay. Now for you folks, contemplating Team Dolphin, this is this sound made by a dolphin.

So which one do you prefer, Team Bat or Team Dolphin? Let's, before we start pulling any punches, let's hear each side's best case for why your animal has the best sonar in the animal kingdom. Laura, you're first up for Team Bat. Give us your case. Okay. Well, first of all, I think the listeners hopefully will clearly agree that just by listening to those two sound files, the bat sounds pretty dramatically different than the dolphins. And that's because the bat signals are about 20 times longer in duration than the dolphin signals are. And by using our ears just from that sound clip, which, by the way, was slowed down about to 10% its original speed,

you can hear the differences in the sounds. And the bat calls have this really beautiful way that the pitch or the frequency of the calls change over time. And we call this, in the science world, we call this frequency modulated. So they have this ability to change how their frequency moves over time. And dolphins really don't have that ability. There sounds, it's pretty boring. It sounds just like a click, right? It sounds like you're snapping your fingers together.

So first of all, bats have the advantage with flexibility in terms of their signal design. And we have lots of scientific evidence that bats modify their echolocation signals depending on their behavioral tasks. So they have a lot of control over how they can change their echolocation calls, both in the frequency and in the time. But I think it's also really important to point out that bats are the clear winner because they evolved echolocation well, before dolphins did. Bats evolved echo. Oh, absolutely. They're the original echolocators.

So they evolved. It depends on the methodology you're looking at, but it's estimated that they evolved echolocation about 65 to 85 million years ago versus dolphins evolved echolocation only a mere 32 million years ago. And then when we start looking at the number of species, bats far surpass the echolocating toothed whales

in that bats, we know, we know. There's still many species we haven't identified. But there's over 1,200 species. of echolocating bats that are found on every continent except for Antarctica. With dolphins, we only have 73. I could go on, but I think maybe we should let team dolphin make their chance. Brian, she called you, you're boring, is the word that she used, dolphin.

Well, we'll see about that. First of all, I think we need to take bats and maybe send them back in time and let them evolve an extra 100 million years, and maybe then they might catch up to what a dolphin can actually do. We're going to start off with something very, very basic. How far away can you detect a target? Now, bats, they can detect targets around three to five meters. That's their maximum range, and that's not very impressive.

A dolphin, on the other hand, it can detect a golf ball-sized sphere out to about 73 meters. They can detect a baseball-sized sphere to about 113 meters, and that's just a bottlenose dolphin. If you were to throw another toothed whale into the group, say a sperm whale, a paper just came out yesterday that suggests that they can actually detect targets out to almost a kilometer. So if you want to do a quick comparison there, a bat three to five meters, a bottlenose dolphin longer than a football field, and a sperm whale almost a kilometer. I think everyone's going to agree that hashtag dolphin biosonar rules. And you guys can put that on your Twitter feed if you want to. Dr. Klepper, what do you say to that? Well, I think, you know, Brian does have some very valid points, but I think it's also really important to point out that sound moves much differently in water than it does in air.

And so dolphins will always have the advantage with target detection range because of the physics of sound in that sound moves faster in water. And the way that sound moves between how the dolphins make their sound and into the water is a little bit more efficient than bats. So we'll give dolphins the win on that. But you really are comparing apples to oranges with the comparison that he used with the ability to teletar at a greater distance. So the other thing to point out is that bats most often use their sonar in very complex environments versus dolphins are usually doing it in the open ocean. So dolphins have a pretty simple task. They just need to figure out where a fish is versus bats are trying to detect a small insect from within a very complex, often forested environment. They just have to do that.

How do you like that, Brian? They just have to do that. Yeah, maybe that's all they have to do, but if that was it, they wouldn't have this crazy capability to do a bunch of things that bats just can't do. One of the main ones is when a bat's echolocating on a target, it's only going to get surface features of it. The echolocation signal cannot penetrate the target. For dolphins, on the other hand, because they are in water,

their echolocation signal can actually penetrate the target. So they can get a lot of information that bats can't get, such as how thick an object is, whether or not objects have different fluids inside of it. For example, a really cool experiment that was done was we have three cylinders. They're geometrically identical, except one has glycerin in it, one has alcohol, and one has water. Dolphins can tell the difference between these no problem.

Bats cannot do that. Another really cool experiment is dolphins can allocate on cylinders that, again, are geometrically identical, except the cylinder wall thickness varies by as small as zero point. That's about twice the width of a hair. It's visually difficult to see the difference, but bats can echlocate on it until the difference. Excuse me, dolphins can echolocated on that until the difference, but bats cannot because their biosonauter cannot penetrate targets. Our number, if you want to phone in on this, and besides, you can tweet us, which do you prefer?

Which radar sonar do you prefer? You can tweet us at SciFRI, or you can give us a call 844724-8-255. is our number. Let's move on to, so far it seems like a tight matchup. Let's move on to prey detection. How are each of these animals able to use this sonar to catch a meal? Laura, you go first. Okay, sure. So with the bats that I'm primarily talking about, I'm speaking about bats that collect insects, so they hunt for insects using their sonar. And so what these bats have is they have some pretty remarkable abilities with detecting their prey using their sonar.

So Brian did mention that dolphins may have the upper hand with determining what an object is made of. But bats can even tell, they can tell the fluttering of a very, very, very small prey object. So they have the ability to detect really small details of their prey so that they can determine whether it's a moth that they want to eat versus some other insect species. The other thing to point out, too, is that bats often fly at really fast speeds. And when you start thinking about sound and speed, you might be your, you're, you're, you're, your brain might take you back to high school physics where you might have learned about the Doppler effect, which is that when you're a moving object and you're making sound, the pitch of the sound that you're making is artificially increased in frequency due to the speed at which you're traveling.

It's why ambulances, they change pitch to a stationary listener as the ambulance moves past. Well, bats have this incredible ability. I like to say that they're doing physics in their head, and they will actually adjust their echolocation signals, depending on their flight speed to compensate for that. And at last I checked, dolphins don't have that ability. Brian? That is true.

That is true. Dolphins do not have Doppler, but it's because dolphins don't need it. Because dolphins don't need to maximum range detection. Since bats are so horrible at detecting targets at range, by the time they actually detect a insect, with Doppler. Dolphins don't need that because they can detect a fish, you know, a football field away. They have plenty of time to swim over there, even produce some whistles and call their buddies over, you know, hey, let's herd these fish into a nice, tight ball, and take our time, you know, maximizing our caloric intake. Bats don't, bats can't do that.

And I don't see Doppler as an extra cool thing that they can do. It's just a compensatory mechanism because they have really horrible maximum range detection. You want to answer that or if I go on to the next question? Well, speaking of buddies, let's talk about buddies, right? So what bats are really good at is using their sonar in large groups. And when you start thinking about any sort of, whether it's an animal or whether it's some sort of synthetic technological device that's using sonar in a group where there's other individuals making sounds and trying to hear echoes, you have this problem of sonar interference. And bats form some of the most dramatic aggregations on the planet. They can live in caves with millions of individuals that all leave the cave often at once,

that are using their sonar. And so they have this ability to overcome what we think is an impossible task by using their sonar in a way that's avoiding what should be interference from other individuals. And so far, we don't really see that dolphins have the extreme ability to do what bats can do. And it really comes down to my first point, which is the flexibility in the signal design. Bats have the upper hand because of how flexible their signal design is, which allows them to adapt to a lot of different scenarios. Brian, what about all that interference underwater from the sounds we keep here? That really hasn't been studied in dolphins.

I will give Laura a victory in one point. A lot of times the bat science is ahead of the dolphin science. And the reason for that is because you can just go up to your attic and grab a couple bats. You know, their accessibility, it's really easy. No one's really going to care. And if you actually read these papers, that's exactly what they do. They go up to an attic, grab a couple bats. Well, you can't go in the backyard and grab a couple dolphins.

So it's a lot harder to do dolphin research. So jamming has not really been studied. Actually, Laura and I are the first people to actually study it in dolphins. But it's a brand new research. There's a lot we don't know about it. But, yeah, bats probably are better at jamming than dolphins are because dolphins pretty much don't need it. They're not living in a cave with seven million.

million other bats that are out in the ocean, usually in smaller groups, but sometimes they do form these super, you know, large groups. And, you know, it's a topic of future research. I'm Ira Flato. This is Science Friday from WNYC Studios. Here with our sonar echolocation Smackdown with Laura Klepper and Brian Steader talking about who are better at doing what they do with their echolocation bats or dolphins. Brian, you want to take it a step further? Have you got something else you'd like to throw in? You know, let's talk about how does each animal actually produce the sonar? And who does it better, Brian?

Well, dolphins produce clicks in their forehead just right underneath their blowhole, right underneath their nasal plug. And if you look at the dolphin skull, it's actually concave shaped, kind of like a radar dish. So it's going to reflect all that acoustic energy in the forward direction. Right in front of that, there's a little. and structure called the melon. This actually acts like an acoustic lens, which further helps focus all that acoustic energy in the forward direction. If you can imagine going out into a

football field and yelling, it might not be that loud, but if you use a bullhorn and focus all that energy forward, you're actually going to increase the amplitude significantly. And if you look at bat echolocation signals, they're only about 100 dB loud. It's not that very loud. If you look at dolphins, on the other hand, bottled nose dolphins, their echolocation signals are above 200 decibels. If you want to talk about really, really, you're really loud, look at sperm whales. Their echolocation signals are around 230 decibels. I think it's the loudest animal sound on the planet. I think if it goes any louder, it starts converting water into vapor, but don't quote me on that one. I'm not exactly sure about that. It's really, really loud.

Now, Laura, how do bats make their sound? Well, Ira, bats make their sounds just like how we make our sounds. So they generate their sounds inside their larynx. And then depending on the species of bat, they either emit the sound through their mouth or through a special nasal structure, so basically through their nose. But they're generating the sounds the same way that we do. And then what's really interesting about the sound generation of bats is that they have pretty remarkable control. Again, coming back to this flexibility, the point I keep making over and over again, they

have a lot of control over the size or the shape of their emitted sonar beam based on the size of the opening of the mouth or the size of the structure in their nose. nose that's generating it. So, yeah, maybe they don't make this the loud, as loud of sounds as the dolphins do, but they have much finer control over the shape of the sonar beam with the structures, with the soft tissue structures that they have on their head. Garrett in Greenville, Georgia, quickly get your question in before we have to go. Hi, welcome to Science Friday. Hello, thank you. I was just wondering, how much of the brain capacity is dedicated to

echolocation in the bat and the person the dolphin. All right, super quick answer. How much? Brian? I have no clue. That's the topic for future research. I mean, I think they've done more of that research with the bat, but it's hard to, you know, it's hard to do that with dolphins. So that's a really good question, but that's a topic of future research.

But I will tell you, a dolphin brain is about 1,500 grams, and a bat, the entire bat weighs about 20 grams. So we're talking about a massive brain with a dolphin, and not much going on with the bat. Okay. Oh, whoa. Sheep shot. Laura. Well, you know, Brian, size doesn't always matter.

Size doesn't always matter, Iron, Brian. Okay, we're going to have to leave it there. Brian Brantzetter is research scientists with the National Marine Mammal Foundation in San Diego, Laura Klepper, Assistant Professor of St. Mary's College in South Bend. Thank you both of being such good sports today on Science Friday. Oh, thank you, Ira. We want to know what our listeners think. Let us know who you think won the match.

We have a poll going on at Twitter right now at SciFri. You can participate in the poll. B.J. Liderman composed our theme music, and a very special thanks to all the great folks here at WUSF, who made us feel so welcome in the studios today, including Greg George, who was working the board for us. And if you missed any part of this program, you'd like to hear it again. Subscribe to our podcast. If you're a smart speaker, ask it to play Science Friday whenever you want. So, you know, every day now is Science Friday.

And, of course, we're active on all social media, Facebook, Twitter, Instagram, you name it. We're there. Have a great weekend. We have our special show next week, our special, you know, Thanksgiving show. The Ig Nobels will be coming up next Friday. A lot of people waiting around to hear that. You'll hear that next Friday. I'm Ira Flato in Tampa.