The Sound Barrier #3: What does silence sound like?

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Speaker 2 Aaron Westgate used to be an optimist.

Speaker 3 When I was in graduate school, we were working on this question of how we could develop well-being interventions to actually make people's lives happier.

Speaker 3 And we had this idea that if we just put people in an empty room by themselves and just gave them a few minutes to be alone with their own thoughts, that they'd really enjoy it.

Speaker 3 You know, people always say, oh my goodness, I'm so busy. I wish I just had a few minutes to sit down and think.

Speaker 2 So Erin recruited a whole bunch of people and she had them each spend 15 minutes in an empty room in total silence.

Speaker 3 And most people didn't enjoy it very much. They said things like brushing their teeth was better.

Speaker 2 They hated it.

Speaker 2 So she decided to flip the whole study on its head.

Speaker 2 Instead of trying to help people feel better, she was going to try and see how bad she could make them feel by giving them the option to listen to horrible sounds instead.

Speaker 3 So like someone throwing up, nails on a chalkboard, glass breaking.

Speaker 3 And sure enough, yeah, people would rather listen to sounds of people vomiting, nails on a chalkboard, et cetera, rather than simply sit in silence.

Speaker 2 At this point, Erin was just morbidly curious. Did people hate silence so much that they'd actually prefer pain?

Speaker 2 Like, what if she put people in an ankle cuff and gave them the option to shock themselves?

Speaker 3 It is not pleasant. It hurts a little bit.
I always liken it to the feeling feeling of like a cat sort of jumping out and scratching you.

Speaker 3 It's sort of like, ah, you know, shocking, but it's not actually harmful. And so we set this all up and we just sort of waited.

Speaker 3 And the first few participants, we just sort of were like, are they going to do it? Are they actually going to shock themselves? But we saw very early on that people were indeed shocking themselves.

Speaker 3 Yeah, I know. So it's like, why, why would you do that?

Speaker 2 Almost half the participants gave themselves an electric shock. They couldn't even make it 15 minutes.

Speaker 3 People actually do something that's painful rather than simply sit in silence.

Speaker 2 The more you think about it, silence is a really strange thing.

Speaker 2 On the one hand, it's so uncomfortable that people would rather shock themselves than sit through it.

Speaker 2 At the same time, silence and other forms of sensory deprivation, they've been shown to reduce anxiety and PTSD.

Speaker 2 There's this one experiment I love where mice were exposed to silence and their brains actually got new neurons, like more neurons than when they were exposed to any other sounds, just from listening to silence.

Speaker 2 I'm Noam Hasenfeld, and this is episode three of the sound barrier, a series from Unexplainable about the limits of hearing and the ways we can break through.

Speaker 2 Today on the show, how can something that's nothing

Speaker 2 do so much?

Speaker 4 So, one of the most striking experiences of silence I've felt is like when I was at a symphony, and the symphony was working up to a kind of crescendo, and like right when it hit the crescendo,

Speaker 4 it ended.

Speaker 4 And the moment before the applause, you're just kind of like hit by this experience.

Speaker 4 And I definitely felt silence like

Speaker 4 hit me across the face.

Speaker 2 Rachel Goh is a PhD student at Johns Hopkins. He studies psychology and philosophy.
And that experience that he had at the symphony, it left him with some pretty basic questions.

Speaker 2 He'd figured silence was just nothing, like the absence of sound.

Speaker 2 But he'd felt it. So the question was, what was he feeling?

Speaker 4 So actually, There's a philosophical literature around this. Some people argue that there is a genuine experience of silence, right? So there's something it's like to experience silence.

Speaker 4 Whereas other people argue that silence is just the absence of experience.

Speaker 2 It sounds like one of those classic von Rip dorm room questions. Like, what is silence?

Speaker 2 But Rejo wanted an actual answer, which would mean he'd have to do an experiment.

Speaker 4 So at that point when I was thinking of the experiment, I was actually kind of fascinated by this illusion.

Speaker 2 Something called the one is more illusion.

Speaker 4 And you'll see in a moment why it's called the one is more illusion. Okay.
Suppose I play you two sounds, right? I play you boop, boop,

Speaker 4 and then I play you a single sound.

Speaker 2 Boo.

Speaker 4 The two sounds and the single sound take up the exact same amount of time, but you will hear the single sound is longer.

Speaker 2 That's why it's called the one is more illusion. One sound seems longer than two.

Speaker 4 Yeah, and one of the great things about auditory illusions is that you can experience it for yourself.

Speaker 2 Is there a website I can go to now to check out?

Speaker 4 Sure.

Speaker 4 Let me just send it to you.

Speaker 2 Okay. Okay.

Speaker 2 One.

Speaker 2 Oh, that sounded way longer.

Speaker 4 Right, right. It's exactly the same length.

Speaker 2 That didn't even sound close.

Speaker 4 Exactly.

Speaker 2 Audio illusions like this one are great ways to learn about how our brain processes sound. They seem like glitches, but they really just show us how our brain is constantly editing the world we hear.

Speaker 2 Like when we're in a room and our voice is bouncing off all the walls and hitting our ears at slightly different times,

Speaker 2 the brain cancels out the echoes so that we only hear a single voice. When there are sounds that are muffled or distorted, the brain can fill them in without us noticing.

Speaker 2 For some people with a cochlear implant, the brain can recreate almost the entire world they hear.

Speaker 2 And scientists think this particular glitch, the one is more illusion, it tells us something pretty fundamental about how our hearing works.

Speaker 4 If you look at the sound waves that enter our ears and you visualize it on the screen, it's going to be a bit of a mess.

Speaker 2 Think about what a waveform looks like. It's just a blobby thing.

Speaker 2 But the world doesn't sound like a blobby thing.

Speaker 2 We hear different individual sounds.

Speaker 4 If you're at a park park and you're talking to a friend and you hear a dog barking in the background, you don't hear a continuous jumble of noise. You hear discrete words.

Speaker 2 This is the big insight from the one is more illusion. Our brain is always on the lookout for discrete sounds.
It's why we're able to pull out individual sounds from a noisy background.

Speaker 2 And it's why the one boop sounds longer than the two boops.

Speaker 2 But Reijo wanted to see if our brain would do the same thing to silence.

Speaker 4 My idea was to try to create a silence version of this auditory illusion.

Speaker 2 Rejo replaced the boop boop with silence silence. His idea was that if these silences cause the same glitch, it would show that our brain is processing silences just like it processes sounds.

Speaker 2 That in a pretty literal sense, we're hearing silence.

Speaker 4 So what we did was in our experiment, our subjects had wet headphones and we immersed our subjects in the ambient noise of a restaurant.

Speaker 4 There would be people talking, plates clinking, people walking around. And then when the trial starts, they would hear a sequence of two silences and then a one-silence sequence.

Speaker 4 And subjects are just asked which one was longer. Was the one silence longer or was the two silence longer?

Speaker 2 And you have an example of this too, right?

Speaker 4 Yep. I think if you play that, you should be able to hear it.

Speaker 2 So I'm in the restaurant.

Speaker 2 Yeah, that's nuts. Okay, that's

Speaker 2 that again that just felt

Speaker 2 it's the same exact feeling. Like the single silence feels way longer than the other two,

Speaker 2 which is basically the same thing as those notes. Yeah, yeah,

Speaker 4 it does definitely feel like it's exactly the same thing happening.

Speaker 2 This one might be a little bit harder to hear the first time through, so I just want to play it one more time.

Speaker 2 Notice how much longer the uninterrupted silence feels compared to the two short ones, even though they're the same amount of time.

Speaker 4 And when we ran this experiment with subjects, we actually found the exact same proportion of subjects felt that one silence sequences are longer than the two silences sequence.

Speaker 4 So it definitely does seem like exactly the same mechanism as I play.

Speaker 2 Wow. And did you try this illusion on yourself? Did it work for you?

Speaker 4 It definitely did work for me. When I created this illusion and played it to myself for the first time, I was like, wow, it works.

Speaker 2 Our brain isn't just editing sounds. It's editing silence.

Speaker 4 Silence is not something out there in the world, and yet we can have an experience of it.

Speaker 2 I mean, your results seem to say that we are hearing the silence. We're not just not hearing anything.

Speaker 4 Yeah, it tells us that like the auditory system treats silences the same way as it treats sounds.

Speaker 2 So if silence is a real thing we can hear, what does it sound like?

Speaker 2 To find out, I decided to go to one of the quietest places on earth. Loud noises.

Speaker 2 That's in a minute.

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Speaker 1 Consider what you're about to do, Paula Treyadis.

Speaker 2 A couple months ago, I hopped on the subway

Speaker 2 and I headed to Cooper Union, this tiny private college in Manhattan.

Speaker 2 To talk with a wonderfully named expert on sound. Hello.
Hi. Melody Baglione.

Speaker 8 Professor of Mechanical Engineering at Cooper Union.

Speaker 2 Can you just tell me a little bit about where we are right now?

Speaker 8 So we're in the Vibration and Acoustics Laboratory, and we also have the only anechoic chamber in New York City.

Speaker 2 An anechoic chamber is designed to be absurdly quiet. It's got double doors.
It's got padding all over the walls.

Speaker 2 It's this place where you're supposed to be able to get as close to complete silence as possible. And anachoic chambers, they're pretty weird.

Speaker 2 There are all these stories about what they'll do to you if you spend too much time in there.

Speaker 2 Stories of people feeling nauseous or starting to hallucinate, or this one violinist who apparently started pounding on the door immediately to get out.

Speaker 2 It's not exactly clear how much these are urban legends and how much of them are actual, real events.

Speaker 2 But it isn't hard to find all kinds of people who've heard these stories and then wrote articles or made videos being like, I survived the quietest room on earth.

Speaker 2 It's a whole thing.

Speaker 8 You know, I've never done really studies to show you can spend this much time here before you go crazy because I'm always so busy that I don't have time to sit there.

Speaker 8 But there are many people that are interested in that question, and I'm asked that a lot, but

Speaker 8 I haven't done it myself.

Speaker 2 Can we go inside? Sure, yeah.

Speaker 2 All right.

Speaker 2 As soon as I walk into the chamber, my ears feel

Speaker 2 different.

Speaker 2 Okay, that feels really, really weird. The only word I can think of to describe the silence is

Speaker 2 thick, like I'm wading into jello or something.

Speaker 2 And the whole place is covered with these wedges.

Speaker 8 So you don't want to touch these wedges because they're fiberglass.

Speaker 2 They're on the walls, they're covering the door, they're on the ceiling, they're even on the floor.

Speaker 2 I'm actually standing on a catwalk suspended from the wall so we don't touch the fiberglass floor wedges. And those wedges are what make the room sound so weird.

Speaker 2 When you're in a normal room, your voice is bouncing off all the walls and the ceiling and the floor.

Speaker 2 You're hearing your voice come out of your mouth, but you're also hearing it reflected off all the other walls and then hitting your ear.

Speaker 2 That's how we're used to hearing sounds. But in an anechoic chamber, the wedges absorb so much of the sound that there aren't echoes.
That's why it's called anechoic, as in without echo.

Speaker 2 And it sounds really strange. Hello! I'm screaming in a room, and it's really quiet.
That's really weird. That's so weird.
To be honest, it's hard to describe how surreal this all felt.

Speaker 2 It was almost like yelling into a black hole, like the sound was being sucked into nothingness.

Speaker 2 The weirdness doesn't exactly translate on a mic, but here's what it sounded like outside the chamber.

Speaker 2 And here's what it sounded like inside. Whoop! Whoop! Hey! Hey! Ho! Ha!

Speaker 2 But the longer I stayed there, the more my ears started to adapt to the silence, just like your eyes might adapt slowly in a dark room. It's extremely, extremely quiet in here.

Speaker 2 And after a couple minutes, I started hearing things. Every noise felt like the volume was just jacked up.
My own breathing started to feel loud. I heard my own heartbeat.

Speaker 2 I feel like I can hear noises from my own head.

Speaker 2 And I can't tell if I'm making them up or not.

Speaker 2 Like, there's this high pitch.

Speaker 2 There's this kind of swirling.

Speaker 2 Almost like I'm putting like a seashell. up to my ear, but like reversed.
Does that make any sense? Like reverse seashell?

Speaker 2 That was just 20 minutes in.

Speaker 2 As my head was swirling in the chamber, I was thinking about this story of one of my favorite composers, John Cage, who also once visited an anechoic chamber on his own quest for complete silence.

Speaker 7 I heard in that room two sounds.

Speaker 7 One was high and one was low. And I thought there was something wrong with the room.

Speaker 2 Cage went outside and he described the sounds to the engineer, who told him that the higher sound was his nervous system, and the lower sound was his circulatory system.

Speaker 7 There's no way to stop the reception of sound. If you stop the sounds from the outside, then what you hear are the sounds that are coming from the inside.

Speaker 5 And now, a performance of John Cage's 433.

Speaker 2 If you've ever heard of John Cage,

Speaker 2 it's probably because of this piece, 433.

Speaker 5 Please welcome our soloist, William Marks.

Speaker 2 In one recording I found, an older man walks out onto the stage wearing a tux with tails and a white bow tie.

Speaker 2 He sits down at the piano, puts on his reading glasses, And then he closes the part of the piano that covers the keys.

Speaker 2 He picks up a stopwatch and holds it up with this kind of conductor-style flourish, presses go,

Speaker 2 and just sits there for four minutes and 33 seconds.

Speaker 2 Cage wrote 433 433 back in the 50s, but it still goes viral all the time. Like, this particular performance has almost 10 million views on YouTube.

Speaker 2 And yeah,

Speaker 2 it might be because people think it's some kind of stunt.

Speaker 2 And the comments are kind of hilarious. Like, I once didn't speak for five minutes and this guy sued me for copyright.
Or, I said this song as my ringtone and nobody called me.

Speaker 2 And I felt the same way when I first heard it. I was in a music class in college, and my professor told us we were going to perform it in class.

Speaker 2 So we pulled up the sheet music. It's basically a whole bunch of nothing divided into three movements of nothing.

Speaker 2 And my professor signaled us to start.

Speaker 2 For a moment, it was silent.

Speaker 2 And then I started to notice little things, like a cough, a chair creaking when someone adjusted their position, this low murmur of voices coming from the hallway outside, my own breath.

Speaker 2 And because I had the sheet music in front of me, I started hearing all these noises almost like they were intentional.

Speaker 2 I heard them interacting. I heard them layering on top of each other.
I heard them getting louder and softer.

Speaker 2 And I started imagining them as if someone had composed them, you know, written them like notes into the sheet music.

Speaker 2 Notes that would be different wherever 433 gets performed.

Speaker 7 The first performance, you could hear the breeze in the trees. And then miraculously, when the second movement began, there were drops of rain that you could hear coming on the roof.

Speaker 7 And you know what happened in the third movement? People began talking because they realized that David Tudor wasn't going to make any sounds. So the sound of people talking was in the third movement.

Speaker 2 Cage was okay with people laughing sometimes. He had a sense of humor.
But 433 wasn't a joke.

Speaker 2 And I do hope that at least some of the people behind those 10 million views on YouTube understood what Cage was doing here.

Speaker 2 He was reframing what silence is and what it can be.

Speaker 7 It doesn't

Speaker 2 She says when she told people not to pay attention to anything around them and just focus on their own thoughts, they spun out pretty quickly.

Speaker 3 People, People's, I don't think their goal is to fill it with anxiety, but it's actually a giant stress induction.

Speaker 2 When people thought of silence as just this empty box, they filled it with their own anxieties. But silence isn't empty.

Speaker 2 Rage's experiment tells us silence is something we can hear, and Cage's piece shows us what it sounds like. It's not nothingness, it's full of noise.

Speaker 2 There's a texture, almost like the particles of air in a room that seems empty.

Speaker 4 There can be beautiful silences. There can be awkward silences.
There can be really powerful silences. Like, I think often an infective speaker makes powerful uses of silence, right? When they pause,

Speaker 4 you kind of feel the weight of their words.

Speaker 2 Silence is something worth paying attention to on its own terms.

Speaker 3 Silence itself is a state of experiencing the world, you know, in the same way that what is the value in the Grand Canyon or what is the value in Mount Everest? Like the value

Speaker 3 is that they're there.

Speaker 3 And so I think that when we think about things like the value of silence or the value of boredom or the value of grief, they're beautiful in their own right.

Speaker 3 And part of the wonder of being human is being able to experience them and appreciate them.

Speaker 2 And sometimes you get a clock chiming right through. Yes.

Speaker 3 This is what happens when you inherit your grandparents' grandfather clock after they die and then actually hang it up and let it do its thing.

Speaker 2 In the last couple of weeks, I've started thinking about silence as turning up the volume knob on my perception. Like right now, I'm speaking in a soundproof room.
It's pretty quiet.

Speaker 2 It's pretty still.

Speaker 2 But wherever you're listening, it sounds different. You're hearing my voice, but you're also hearing the ambient sound of wherever you are.

Speaker 2 Maybe it's a light echo in your room, or the idling traffic as you cross the street, or the tiny buzz from a fluorescent light.

Speaker 2 So,

Speaker 2 I don't know. Maybe this is weird.
But what if we just spend a little time in that silence?

Speaker 2 You're going to have your own particular kind of silence with its own particular small noises. I'm gonna have mine.

Speaker 2 But yeah,

Speaker 2 let's uh

Speaker 2 let's listen to the silence and see what we can hear.

Speaker 2 That was four minutes and 33 seconds of silence. And this was the third episode of our series, The Sound Barrier.

Speaker 2 We'd love to know what you thought of when you were listening to your own silence. What did it sound like? What did you hear?

Speaker 2 Or if you want to record a voice memo of silence wherever you are and email it to us at unexplainable at vox.com, we'd love to hear it too.

Speaker 2 On the next episode of The Sound Barrier, How a Blind Astronomer Learned to Listen to Space.

Speaker 3 I thought those sounds were bothersome and ugly. And at that moment, everything transformed into beauty.

Speaker 2 That's next time.

Speaker 2 As for this episode, it was reported and produced by me, Noam Hasenfeld. I also wrote the music.
It was edited by Joanna Salatarov with help from Jorge Just.

Speaker 2 Mixing and sound design from Christian Ayala. Fact-checking from Melissa Hirsch, and silent support from Sally Helm.

Speaker 2 Meredith Hodnott runs the show. Julia Longoria is our editorial director.
And Bird Pinkerton ran towards the wooden carriage as the octopus army stampeded onto the runway.

Speaker 2 She hoisted the octopus onto her shoulders, and she turned to face the chaos.

Speaker 2 Thanks to Vartika Sharma and Paige Vickers for the beautiful artwork for the Sound Barrier series. Thanks to Robert Liu.

Speaker 2 Thanks as always to Brian Resnick for co-creating the show along with me and Bird. And if any of you out there have thoughts about the show, send us an email.
We're at unexplainable at Vox.com.

Speaker 2 You can also leave us a review or a rating wherever you listen. Really helps us out.
And if you're really into supporting the show and all of Vox in general, join our membership program.

Speaker 2 You can go to Vox.com slash members to sign up. Unexplainable is part of the Vox Media Podcast Network, and we'll be back with the final episode of the Sound Barrier on Wednesday.

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