December 10, 2024 • 49 mins
What is sound? And what does it mean to listen? In this episode, we take a closer look at sound: what it is, how it works, and how what you hear may not be the same as your neighbor.
Threshold is nonprofit, listener-supported, and independently produced. You can support Threshold by donating today. To stay connected, sign up for our newsletter.
We want to hear from you! Send us your questions about the new season, the content or how it’s made, for an upcoming behind-the-scenes episode. You can submit your questions to outreach@thresholdpodcast.org
Resources:
Check out more from Evelyn Glennie on YouTube and on her website.
Mark as Played
Transcript
Episode Transcript
Available transcripts are automatically generated. Complete accuracy is not guaranteed.
Amy Martin (00:00):
If you stand in front of a classroom full of
(00:01):
kindergarteners and ask themwhat an ear is, chances are good
that they'll think you're kindof silly. Everybody knows what
ears are, those floppy things onthe sides of our heads, the
things we hear with but what ifyou were to pose that same
question to a classroom full ofspiders?
Dr. Natasha Mhatre (00:22):
So this is going into the fun part of my
Amy Martin (00:25):
Dr Natasha Mhatre researches how insects and
research.
spiders process sound at theUniversity of Western Ontario,
and she says that scientistsused to think that spiders
couldn't hear airborne soundbecause they didn't seem to have
any obvious ear like structures.
Dr. Natasha Mhatre (00:43):
That used to be the received wisdom. There's
now different pieces of evidencefrom other labs, including some
evidence we've just collectedthat suggest that they can hear
airborne sound.
Amy Martin (00:53):
Where would their ears be?
Dr. Natasha Mhatre (00:55):
So that's the big question.
Amy Martin (00:58):
Natasha says she and other researchers are now coming
to understand that it's notnecessarily that spiders don't
have ears. They might just lookreally different than ours.
Dr. Natasha Mhatre (01:10):
Okay, so there's some evidence that one
of the ways that they hear iswhen air hits the web of some
spiders, it makes the web move,and they can sense the vibration
of the web, so they're kind ofmaking their own ear drum.
Amy Martin (01:24):
The web is the ear.
Dr. Natasha Mhatre (01:25):
The web is the ear.
Amy Martin (01:27):
How cool is that?
Dr. Natasha Mhatre (01:28):
That is pretty neat, because you can
make whatever ear you want,right? If it gets damaged, you
can just make yourself a newear. Really cool.
Amy Martin (01:40):
Welcome to Threshold, I'm Amy Martin, and
we're going to hear a lot morefrom Natasha in our next
episode. But I wanted to startout with this fun little factoid
about spiders just to shake upour perceptual framework. We
think we know what ears are. Wethink we know what it means to
listen, but those ideas areusually just drawn out of our
(02:02):
own very limited experience. Andspeaking of things we think we
know but maybe don't, what issound? Like, if you had to
define it right now withoutlooking anything up, what would
you say? Even though I work inaudio, I didn't really have a
(02:22):
clear answer to that questionbefore making this season of our
show. Sound is one of thosethings that's so much a part of
my everyday life that it's easyto forget how mysterious it
really is. It's everywhere, butit's invisible. It's flowing
into my brain every wakingmoment and when I'm asleep it
turns out, affecting my mood, myenergy level, my sense of
(02:45):
connection to wherever I am andwhoever I'm with. But what is it
actually? The answer to thatquestion is not as
straightforward as you mightexpect, so in this episode,
we're going to press pause onour timeline of listening to
examine the nature of sounditself, what it is, how it
(03:06):
moves, and how wildly differentour experiences of it can be.
We're going to tap into a secretcommunication network happening
all around us, pay another visitto the dolphins of Shark Bay and
talk to a world famous composerabout how much more there is to
listening than what meets theear.
(03:57):
I'm walking through a Montanaforest. The breeze is rustling
through the trees. There's acreek flowing nearby, and one of
my favorite birds is unleashingits song again and again. It's a
Swainson's thrush, and I loveits song. I think it sounds like
a waterfall flowing up. Chancesare good that you have a bird
(04:21):
song you love too, and even ifyou don't, almost all of us hear
birds singing every day. So in away, this experience I'm having
is completely ordinary. But if Izoom out a bit and think about
what's actually happening here,it's kind of marvelous.
Something that originates insidethe body of a small bird hidden
(04:43):
in the branches above me istraveling across the forest and
landing inside my ears andultimately in my mind, where it
becomes this beautiful, melodicthing with the power to change
my mood and lift my spirits. I'mreceiving something from this
thrush, something is beingtransferred between us, and it's
(05:05):
affecting me. But what is thatsomething exactly? What is
sound?
Dr. Lily Wang (05:11):
So at its heart it is an energy in the form of
vibrational waves in matter.
Amy Martin (05:18):
Dr Lily Wang is an engineer who teaches and studies
acoustics at the University ofNebraska in Lincoln. She fell in
love with sound as a child theway many people do: through
music.
Dr. Lily Wang (05:30):
I love singing. I have loved singing since I was a
little girl, and I've alwaysbeen in choirs, and then I did
also play piano.
Amy Martin (05:39):
I asked Lily to give me a crash course in the
fundamentals of sound, and shestarted with the fact that
there's a wide range of soundwaves, and we can only hear a
portion of them.
Dr. Lily Wang (05:49):
We call it the audible range. The most common
definition of the audible rangeis 20 hertz to 20,000 hertz.
Amy Martin (05:57):
To help make those numbers mean something, here's a
tone moving across that wholerange. It takes about 30
seconds.
(06:29):
But this so called audible rangeshould really be called the
human audible range. Elephants,pigeons and many other animals
can hear well below what we candetect, that's called infrasound
and all sorts of other creaturescan hear way higher than we can
in the ultrasound range. Dogscan pick up frequencies twice as
(06:50):
high as our upper limit. Catscan hear four times higher. And
many dolphins can hear seven oreight times higher than us, up
to 150,000 hertz. That's higherthan almost all other
vertebrates on the planet,except bats. Again, humans top
out at around 20,000 hertz, orfor many of us, significantly
(07:12):
lower.
Dr. Lily Wang (07:13):
I really can't hear above 8,000 hertz anymore.
You know, there are bats in myhouse at certain times of the
year, and I cannot hear them.Like I can see my children go...
woo!..they twist their headslike they can hear that the bats
are back and they're nesting,sadly, in our house, and they're
like, squeaking, but it's atlike, it's probably at like, 10,
(07:36):
12,000, hertz. I do not hear itat all.
Amy Martin (07:39):
Here's what 10,000 hertz sounds like. If you're not
hearing anything, don't worry.You are definitely not alone.
Dr. Lily Wang (07:48):
It's the most common disability among humans
is that we lose hearing and mostoften at that higher frequency.
Amy Martin (07:56):
In fact, some amount of hearing loss is almost
inevitable as we age and ofcourse, some people don't hear
any airborne sound at all. We'regoing to talk to one of those
people later in this episode,but Lily says this measurement
of how we hear sound wavesmoving through the air is really
just one relatively narrowdimension of our lived
experience of sound. All kindsof other factors affect our
(08:19):
listening experience, thetemperature and humidity of the
air, what other sounds arehappening at the same time, the
shape and texture of the spacewe're in, and that includes the
most intimate space of all, ourown individual bodies.
Dr. Lily Wang (08:34):
The shape of your ear, the shape of your head, the
shape of your body, all thesethings are affecting how that
sound wave approaches you.
Amy Martin (08:42):
This is why our voices sound weird in our own
ears. When we hear ourselves onrecordings, we're actually
experiencing the sound verydifferently when it's coming at
us in the air through a speaker,versus hearing it from inside
the place it's produced, theresonating chambers of our own
bodies.
Dr. Lily Wang (09:00):
The fact that we are part of this experience does
actually morph how that wavegets into our head.
Amy Martin (09:07):
So you and I could be walking right next to each
other listening to the sameSwainson's thrush calling in the
forest, and the differences inthe shapes of our bodies means
we'll be hearing slightlydifferent things. But however
the sound waves are ultimatelyreceived, they all start the
same way, with a vibration.
Dr. Lily Wang (09:28):
Something that is moving, something back and
forth.
Amy Martin (09:32):
From there, a whole lot of things happen one after
the other really, reallyquickly. So let's try to follow
the journey of that Swainson'sthrush song step by step, from
creation to reception. In birds,as with humans, song begins with
breath. This thrush pushes airout of its lungs and through a
(09:56):
special organ called the syrinx.It's set up differently from the
human larynx or voice box, butthe basic concept is the same.
The bird squeezes the musclesaround the syrinx, setting air
molecules into motion, and whenit opens its mouth, that
vibration is then passed throughthe air, molecule to molecule
(10:17):
like a baton.
Dr. Lily Wang (10:19):
It's pushing these particles, which push the
next particles, which push thenext particles.
Amy Martin (10:23):
It's an incredibly fast relay race, moving from the
bird across the forest and intomy ears.
Dr. Lily Wang (10:35):
But once it gets into the ear, it's traveling
down and it eventually hits amembrane that is physically
attached to three of thesmallest bones in your body.
Amy Martin (10:47):
That membrane is called the eardrum, and it is a
lot like the tight, bouncy topof the drums we use to make
music, except it's only about acentimeter wide. That's less
than half an inch, the vibratingmolecules of air hit that drum,
making it shake, and that causesthose teeny, tiny bones called
(11:10):
the ossicles to move, one afterthe other, which shakes a second
membrane...
Dr. Lily Wang (11:18):
...that is then connected to fluid inside the
cochlea.
Amy Martin (11:23):
The cochlea is a fluid-filled tube coiled up like
a snail shell or the world'stiniest cinnamon roll, and when
the vibration that began withthe breath of the bird is
transferred into the cochlea, itsends ripples through the fluid
inside, almost like wavesrolling across a miniature
(11:43):
ocean. And lining the inside ofthe cochlea, swaying in the
fluid, guess what we find?Cilia. Tiny little hairs like
the ones that grow on the bodiesof baby corals. Under a
microscope, they look like seagrasses, flexing and bending as
(12:05):
the waves of sound roll overthem.
And as they move in response tothe sound energy, the cilia
perform one of the greatestmagic tricks in the human body.
They transform this physicalvibration into a spark of
(12:28):
electricity, which then shootsoff to the brain through the
auditory nerve, where we processit as a sound.
Dr. Lily Wang (12:36):
And all this happens so fast, like, so fast,
like, in an instant!
Amy Martin (12:41):
343 meters per second, give or take, that's
more than three football fieldsin the snap of a finger.
Dr. Lily Wang (12:48):
So quickly. It's just miraculous.
Amy Martin (12:54):
So to recap the process, the vibration starts in
the body of the bird. Thatenergy is passed across the
forest into my ear canals, whereit hits the drum that moves the
bones that hit the other drumthat shakes the fluid, which
bends the cilia that turn thevibration into electricity that
goes to my brain, in less than asecond. And that's the
(13:18):
simplified version, but asquickly as this vibration is
transferred from the bird to meas I walk through the forest,
the movement of sound and air isactually relatively slow. Sound
moves more than four timesfaster in water compared to the
air.
Dr. Stephanie King (13:36):
This, this.
Laura Palmer (13:38):
This is what we do.
Dr. Stephanie King (13:39):
This is it. This is paradise.
Amy Martin (13:42):
We'll have more after this short break.
Welcome back to Threshold, I'mAmy Martin, and I'm in Shark
Bay, Western Australia, scanningthe horizon for dolphins.
(14:06):
I keep seeing something way outthere.
Dr. Stephanie King (14:08):
Yeah, that was another dolphin. Yeah, yeah.
Amy Martin (14:11):
That's Stephanie King, co-director of Shark Bay
Dolphin Research.
Dr. Stephanie King (14:15):
So we're approaching what we call glass.
There's hardly any wind, andthen you really see how many
dolphins there are in Shark Bay,because you just start to see
them everywhere.
Amy Martin (14:23):
So cool.
In our first episode, we metStephanie and her field team and
a few of the two or 3000dolphins that live in these
waters. Now it's the afternoonof that same day. The heat is
upon us, the wind has died down,and we're moving slowly across
the water.
It's the most beautiful, blue,green water, it's just perfect.
(14:49):
Up ahead, a small group ofdolphins is gathered at the
surface. They're not swimming orjumping. They're just kind of
hanging out there in the calm,quiet waters. Stephanie explains
what's going on.
Dr. Stephanie King (15:02):
You'll sometimes see dolphins in Shark
Bay, what we call snagging. Thisis when they're resting at the
surface, so the whole body'sjust flat on the surface. And it
was because in Australia, yousnag sausages on the barbie,
like snagging. They're calledsnaggers on the barbie, and it
looks just like a sausage lyingat the surface.
Amy Martin (15:20):
But these floating sausages are actually much more
active than they appear. Adolphin doesn't lose
consciousness when it rests, orat least not all the way. Half
of its brain remains engaged inthe work of breathing, which it
needs to come to the surface todo, and stays alert to what's
happening around it, and thatmeans listening.
(15:46):
Researcher Laura Palmer flips onthe speaker in the boat
connected to the underwatermicrophones, and we're suddenly
dropped into a conversation.
These are echolocation buzzes,pulses of sound that the
(16:07):
dolphins send out in order togather information about their
world.
Dr. Stephanie King (16:13):
They wait for the returning echo, and so
the closer they get to a fish,the more they are echolocating
so they can use their returningecho to work out distance and
shape.
Amy Martin (16:24):
It's remarkable to be able to listen in as the
dolphins do this, but it wouldbe even more mind blowing to
experience these sounds the waythey do. Dolphins aren't only
detecting a much wider range ofsounds than we do, the whole
nature of their sonic experienceis something we can only sort of
guess at. These echolocationbuzzes are beams of acoustic
(16:50):
attention, and they come back tothe dolphins packed full of
information that their brainshave evolved to process at
lightning speed.
So what sounds to us like acontinuous buzz, to them, it's
like really fast echo locatinghappening?
Dr. Stephanie King (17:07):
Exactly. Really, really fast clicks. So
they're like pulsedvocalizations, and they produce
them so rapidly, so sometimes itsounds like it's almost a
continuous vocalization.
Amy Martin (17:21):
Dolphins can actually use echolocation to
perceive the insides of objects.If I jumped in the water with
this group, they'd be able tosense not just my outer
surfaces, but my bones andlungs. They would perceive me in
a way I could never perceivemyself, and they'd be doing it
using sound.
Dr. Stephanie King (17:43):
Here we go, snaggers.
Amy Martin (17:45):
We've come upon another group of resting
dolphins.
Dr. Stephanie King (17:48):
Snagging, see. Just resting at that
surface, like a...
Amy Martin (17:52):
Sausage on the barbie.
Dr. Stephanie King (17:53):
Sausage on the barbecue. Exactly.
Amy Martin (17:59):
Stephanie says dolphins use echolocation
primarily to help them find foodand for navigation. But even
now, when they appear to bedoing little to nothing, there
is some echolocating going on.It's like they're casually
scanning the environment, justkeeping the ear out, except that
ear isn't where we might expectit to be on their bodies.
Dr. Stephanie King (18:20):
They receive sound through the lower jaw, and
that sound then goes up to themiddle and in the ear. So when
they're snagging like that andresting, you sometimes see them
their lower jaw is still in thewater, and they're kind of
moving their head side to side,as if they're scanning, right?
They're not vocalizing. They'reactually listening for sounds of
other dolphins, if you like. Sowe typically see that when maybe
(18:42):
they're waiting for a dolphin tocatch up, or there's about to be
a join, and they'll turn aroundand they're scanning, and
they've obviously detectedsomething, and then they're
having a good listen to see whomight be close by.
Amy Martin (18:51):
But with dolphins and other animals that live in
the water, the whole idea ofclose by has to be redefined.
Acoustic vibrations don't onlyhappen faster underwater than in
air, they also do a better jobof holding on to their power as
(19:13):
the vibration is transferredfrom molecule to molecule, it
doesn't lose as much energy witheach pass of the baton, and that
means underwater sounds can stayloud for a much longer time. So
what feels very far away inhuman terrestrial life might
feel quite nearby to a fish or aseal or a dolphin.
Laura Palmer (19:36):
And Rockette just surfaced 80 degrees.
Amy Martin (19:41):
There's a little flurry of extra buzzing from the
group as a dolphin namedRockette pops up and joins them,
but there's no visible change inthe dolphins' faces. It's not
like they're opening theirmouths to echolocate. I asked
Stephanie how they are producingthese sounds, and she says, as
with our vocalizations, itbegins with air pushing through
(20:03):
tissues in the dolphins' bodies.
Dr. Stephanie King (20:05):
They basically have these phonic
lips, these two lips they canpush together and then force air
through that then causesvibrations of different tissues
within that chamber. And it'sthe tissue vibration which
creates the sound, essentially.
Amy Martin (20:21):
I love how they're performing, right on cue, as
you're talking about it, theystarted doing it.
Dr. Stephanie King (20:25):
Yeah!
Amy Martin (20:27):
That vibration then passes through a pillow of fatty
tissue in their foreheads calledthe melon. It acts as a sort of
acoustic lens, focusing andamplifying the sound, which is
then project it out throughtheir heads. We think of making
sound as one thing and receivingit as another, but one of the
(20:49):
things I find most intriguingabout echolocation is that it's
both at once. It's a way ofmaking sound in order to listen.
It takes the whole idea ofactive listening to a completely
different level. Dolphins candecide to shoot a beam of
listening toward another dolphinor an approaching fish, kind of
(21:09):
like the way we might flip on aflashlight in order to see into
a dark corner of a room. Andthey can manipulate that
echolocation beam, they can makeit stronger or weaker, wider or
narrower, and if somethingattracts their attention, they
can turn up the dialinstantaneously and send out a
(21:32):
bright, strong pulse of acousticenergy homing in on whatever it
is they want to investigate.That's what seems to have
happened with Rockette, becauseshe suddenly left her group and
zoomed right under our boat.
Dr. Stephanie King (21:47):
There we go, Rockette in the bow. Hi,
Rockette!
Amy Martin (21:51):
Oh, hi. Hey, beauty. Oh, right underneath us. Oh, my
gosh. I mean I can reach out myhand and touch her. Wow.
It's not us she's curious aboutit's a patch of sea grass below
us in the crystal clear water,we can see her twisting and
(22:13):
turning herself through it.
Dr. Stephanie King (22:15):
So we saw Rockette just come up and rub
herself in a sea grass patch.And we see that a lot with the
dolphins, and we'll call itseagrass play. Or they seem to
come up and drape it over theirbody and even rub themselves
against it, I think just becauseit feels nice. But you see that
quite often. And she obviouslypeeled off from the group,
spotted that seagrass patch andwent over there and started
(22:36):
rubbing herself underneath itbefore returning to the group.
Amy Martin (22:38):
It looked a little bit like a dog growing on a mat.
Dr. Stephanie King (22:42):
Yeah, exactly, and you know, they do
that. It's fun. They enjoy. Itfeels good. Same for the
dolphins.
Amy Martin (22:52):
Lots of animals use echolocation, orcas and sperm
whales, some small burrowingland mammals, and, of course,
the most famous echolocators ofall, bats. The common
denominator here is darkness,where vision is diminished, the
clicks, chirps and buzzes ofecholocation can help animals
(23:13):
navigate their worlds, andhumans can learn to echolocate
too. Many people with visualdisabilities become experts in
it, but even the most highlyskilled person can't come close
to what dolphins can do.
(23:37):
Echolocation is only one of theways dolphins use sound in
future episodes, we'll be comingback to Shark Bay to listen to
their whistles and pops, soundsthey use to communicate with
each other and even to identifythemselves. But now it's time
for us to return to theterrestrial realm, to meet these
mysterious creatures that areusing sound in yet another
(24:00):
fascinating way. We'll have moreafter this short break.
Matt Hurley (24:18):
Hi, my name is Matt Hurley, and I've been a
Threshold listener and donorsince season one came out in
2017. I was also one of thefirst volunteer board members of
the nonprofit organization thatmakes Threshold. Over the past
seven plus years, I've had thisunique first hand look at just
how much work it takes to makethis kind of show. I mean, the
the time, the dedication, thedetermination that's required to
(24:39):
tell these, in depth storiesreally make people think and
feel, and give people a sense ofwhat it's like to really go to
places where the stories arehappening, to talk to the people
who are part of them. It createsthis rich, immersive listening
experience. And it's like thatkind of reporting, this whole
kind of show, is not easy tomake. It's also not easy to
fund. Talk about slow, in-depth,thorough. These are not often
(25:01):
part of the existing models formaking a podcast. So it's up to
people like us to really makesure Threshold can get made. I
believe what Threshold is doingreally matters, and if you do
too, help them keep doing it.Threshold's year end fundraising
campaign is happening right nowthrough December 31 and each
gift will be doubled throughNewsMatch. So if you give $25
(25:22):
they'll receive 50. You can makeyour one time or monthly
donation online atthresholdpodcast.org. Just click
the donate button and give whatyou can. Thank you.
Amy Martin (25:39):
Hi Threshold listeners. Do you ever find
yourself wondering whatbusinesses are doing and what
more they should do to confrontclimate change? Then you should
check out Climate Rising, theaward winning podcast from
Harvard Business School. ClimateRising gives you a behind the
scenes look at how top businessleaders are taking on the
challenge of climate change. Theshow covers cutting edge
(26:02):
solutions, from leveraging AIand carbon markets to sharing
stories that inspire climateaction. Recent episodes feature
insightful conversations withleaders like Netflix's first
sustainability officer, EmmaStewart, who discusses how the
global entertainment giant usesits platform to promote climate
awareness. You'll also hear fromCNN's chief climate
(26:24):
correspondent, Bill Weir, aboutthe importance of integrating
climate change into newscoverage. Each episode dives
deep into the challenges andopportunities that climate
change presents to entrepreneursand innovators. Listen to
Climate Rising every otherWednesday on Apple podcasts,
Spotify, or wherever you getyour podcasts.
Dallas Taylor (26:49):
I'm Dallas Taylor, host of 20,000 Hertz, a
podcast that reveals the untoldstories behind the sounds of our
world. We've uncovered theincredible intelligence of
talking parrots.
Unknown (27:01):
Basically, bird brain was a pejorative term, and here
I had this bird that was doingthe same types of tasks the
primates.
Dallas Taylor (27:10):
We've investigated the bonding power
of music.
Unknown (27:12):
There's an intimacy there in communicating through
the medium of music that can bereally a powerful force for
bringing people together.
Dallas Taylor (27:22):
We've explored the subtle nuances of the human
voice.
Unknown (27:25):
We have to remember that humans, over many hundreds
of thousands of years ofevolution, have become extremely
attuned to the sounds of eachother's voices.
Dallas Taylor (27:33):
And we've revealed why a famous composer
wrote a piece made entirely ofsilence.
Unknown (27:38):
I think that's a really potentially quite useful and
quite profound experience tohave.
Dallas Taylor (27:43):
Subscribe to 20,000 Hertz right here in your
podcast player. I'll meet youthere.
Dr. Rex Cocroft (27:55):
So now we're hearing their mating signals.
Amy Martin (28:00):
Welcome back to Threshold, I'm Amy Martin, and
we're back in the United Statesnow with Dr Rex Cocroft and a
group of wild animals. I'm notgoing to tell you what they are
right away, just listen andguess.
Dr. Rex Cocroft (28:16):
Two or three different males.
Amy Martin (28:17):
So cool.
Here's a hint. These animals aremuch, much, much smaller than
dolphins. They live all over theworld, and millions of people
walk by them every day as theymake these sounds. But we don't
hear a thing. This sound is madeby a treehopper, a teeny little
(28:43):
insect about the size of asunflower seed without the
shell. It communicates byshaking its abdomen, which sends
waves of vibrations through itslegs and out into the stems and
leaves of plants. Other treehoppers can feel those
vibrations with their legs, andthey often respond with their
own belly shakes.
Dr. Rex Cocroft (29:03):
And it doesn't look like they're doing anything
at all. There's stationary. Ifyou're really close, you can see
their abdomen moving when theysignal. But otherwise it just
looks like like nothing ishappening.
Amy Martin (29:15):
And ordinarily it also doesn't sound like anything
is happening. These treehoppercalls don't get broadcast out
into the open air. It's not justthat these insects are small and
their calls are quiet. Thevibrations they make don't leave
the body of the plant. We'reonly able to hear them now
because Rex has hooked up aspecial microphone to the plants
(29:38):
and connected it to somespeakers.
Dr. Rex Cocroft (29:41):
If I turn the speaker down, you don't hear
anything. And we're standingright next to this plant, and
you could put your ears rightnext to me, you really don't
hear anything.
Amy Martin (29:49):
So these little insects are talking to each
other through a secret world ofsound called the vibroscape.
Instead of air or water, theseacoustic waves are moving
through the bodies of livingplants.
Dr. Rex Cocroft (30:03):
It's like they take a different train, sec
through acoustic space and puttogether sound in ways that we
never thought to do.
Amy Martin (30:12):
So what is going on here? How is it possible that
these sounds are happening allaround us, but we can't hear
them? and how did Rex break thecode? Well, it helps that he had
an early interest in music likeLily Wang, and later he combined
that with a love of biology andanimal communication. He studied
(30:35):
frogs at first, but one day inthe 1990s, Rex decided to find
out if treehoppers had anythingto say.
Dr. Rex Cocroft (30:43):
I just walked out onto a meadow near where I
lived. I was at Cornell, so thiswas upstate New York, very
beautiful place in the summer. Ihad a tape recorder. It was a
cassette tape recorder andheadphones.
Amy Martin (30:57):
He found a goldenrod plant with some tree hoppers on
it, and leaned a microphoneright up against it.
Dr. Rex Cocroft (31:04):
And immediately I heard these wonderful sounds.
I'd never heard it before, thistiny insect, this beautiful
song. And then I was hooked. Inever looked back. It was a
sound that I was completelyunfamiliar with, and I could be
(31:26):
confident that no human had everheard that sound before, and
that's still true with most,most insects that communicate
through plants. You listen tothem, and probably nobody's ever
heard that sound before.
Amy Martin (31:42):
And that's basically just because we haven't been
listening. We couldn't hearanything, so we thought there
was nothing to hear.
It's almost like the treehoppersturn the plants and their own
bodies into musical instruments.That's partly what captivated
(32:04):
Rex about these sounds the firsttime he heard them.
Dr. Rex Cocroft (32:07):
To me, it was totally different when I
expected, because it had, it waslike harmonically structured,
and it was changing in pitch,and it was very exciting.
Amy Martin (32:18):
Before we knew anything about their sonic
lives, treehoppers had attractedattention because of their
appearance.
Dr. Rex Cocroft (32:24):
They look like miniature cicadas, and they have
a kind of roof over their backthat in many cases, is very
elaborate and whose function westill don't really know in many
cases.
Amy Martin (32:37):
The treehoppers that Rex studies the most are called
thorn bugs, and they look likerose thorns that can walk. Other
tree hoppers look like they havesand castles on their heads or
bird droppings.
Dr. Rex Cocroft (32:49):
Others have what looks like a little
Starship Enterprise in theirback, a lot of interesting
forms, and others, it's just asmooth roof.
Amy Martin (32:57):
So treehoppers are kind of the quirky rock stars of
the insect world pushing theboundaries of fashion and sound.
This next one might be myfavorite. Its scientific name is
potnia brevicornis, but I thinkof it as Rage Against the
Machine.
Again, this hidden world ofacoustic signaling is called the
(33:26):
vibroscape, and I love thatterm, but it also made me
wonder, since waves of vibrationare happening anywhere there's
sound, isn't the vibroscape sortof everywhere? I put the
question to Rex.
Is there a sharply defined linebetween a sound and a vibration?
(33:47):
Because my understanding is thatall sounds are vibrations. So
why aren't all vibrationssounds?
Dr. Rex Cocroft (33:53):
They're very closely connected, and it
depends on the sensorystructures that you use to pick
them up and how your nervoussystem then relays that
information to your brain.
Amy Martin (34:04):
We can experiment on ourselves in real time to
understand this. If you'replaying this episode through a
speaker in your house or yourcar right now, and you crank up
the volume, you might be able tofeel the music vibrating the
floor or the steering wheel. Ifyou're a person who hears
airborne sound, you can alsohear those waves as they hit
(34:27):
your eardrums. The waves ofvibration have the same source,
the music, but they can beperceived through two different
sensory systems.
Dr. Rex Cocroft (34:36):
It's all the same thing. It's all mechanical
energy that's propagatingthrough an environment, whether
it's a structure, whether it'sthe air, whether it's the water,
but you have to have a differentkind of sensor to pick it up. So
for us, our vibration sensorsare totally different from our
ears and the information fromthose we feel it different. It
(35:00):
goes to different parts of ourbrain, and so that's what makes
it so different.
Amy Martin (35:04):
For us.
Dr. Rex Cocroft (35:05):
For us, right. For us.
Amy Martin (35:11):
Our experience of these two waves of vibration is
bifurcated into two differentsensory systems, hearing and
touch, but that's just areflection of the way our bodies
happen to be put together.
Dr. Rex Cocroft (35:24):
For other animals, they may be just two
sides of the same coin, like theones that I study, these insects
with their six legs, and theyhave vibration sensors in their
legs, but some of thosevibration sensors also act as
pickups for airborne sound. AndI don't honestly know how they
tell the difference sometimes.How do they know if it's a sound
(35:46):
or a vibration, if they'repicking it up through their
legs? And I'm not really surethe answer to that.
Amy Martin (35:55):
Or maybe the whole question of what defines sound
versus vibration only makessense from within our own
perceptual framework. Maybe ifyour senses of touch and hearing
are more unified, there is nodifferentiation, really.
Dame Evelyn Glennie (36:10):
We're actually incredibly gifted
listeners. You know that isinherent to being a human being.
We have the capacity to listen.I think it's a categorization of
the word "listen" that getsreally confused.
Amy Martin (36:25):
Dame Evelyn Glennie is a world renowned
percussionist and composer.She's also deaf. She doesn't
hear airborne sound waves, butshe says listening is available
to everyone.
Dame Evelyn Glennie (36:39):
You know, we think about hearing, and
Amy Martin (36:39):
Evelyn grew up in rural northern Scotland, helping
that's something that can bemeasured. That's something that,
out on her family's farm, andshe says the patience that
you know, medically, we can seewhether that person can hear a
certain frequency at a certainvolume. However, listening is
farming requires gave her someof her first formative lessons
not something that can bemeasured medically. Someone can
be born deaf, but they can beamazing listeners.
(37:10):
in listening.
Dame Evelyn Glennie (37:11):
Because listening is all about patience
that I have learned over time.So you can't force a field to
grow corn any quicker than itwill grow the corn according to
the season and the weather. Youknow, you can't dictate when a
sheep will give birth to a lamb.It will just naturally give
birth to a lamb as and when thattime is right. You know, there
(37:33):
are certain things that justneed to happen naturally. And so
I think that is very much to dowith listening. You know, is
that we can control a certainamount, but ultimately, we also
have to work in partnership withthe existence that we're in,
with the environment that we'rein.
Amy Martin (37:53):
Evelyn had already exhibited a strong interest in
and talent for music when shebegan to lose her hearing around
the age of eight.
Dame Evelyn Glennie (38:02):
I realized that one aspect of the body was
no longer working as it used towork.
Amy Martin (38:09):
But this change did not stop her development as a
musician. In fact, it seems tohave enhanced it. When she began
studying percussion at age 12,her teacher suggested she take
out her hearing aids and tuneinto other ways of sensing the
music. That's when she startedto learn how to listen with her
whole body, to pay attention tothe vibe escape.
Dame Evelyn Glennie (38:33):
It's simply the knowledge that sound is
vibration, that is what soundis, and therefore our bodies are
a resonating chamber. So if I'mplaying a glockenspiel or cymbal
or triangle or anything withhigh frequencies, it's more than
likely going to touch the faceand the upper part of the body.
(38:54):
However, with low, low sounds,such as playing bass drum or
timpani, or anything with areally low, resonant sound.
Obviously the vibration is quitewider and bigger, and that will
reach a larger part of yourlower part of the body. So you
know, your tummy, your chest,down your legs, your feet,
through the stage and so on.
Amy Martin (39:16):
Evelyn has developed her ability to feel differences
in pitch, tone and musical colorat a much subtler level than
most people, and used thoseskills to become one of the most
celebrated percussionists of alltime. She composes for the
concert hall, for films and fortelevision, and she performs all
(39:36):
over the world. She's wonmultiple Grammy Awards, the
Polar Prize, and a long list ofother honors. Clearly, she has a
musical force in her that wasnot going to be denied no matter
what. But even though we're notall going to become musicians of
Evelyn's caliber, she insistsanyone can learn to sense sound
(39:57):
as a whole body experience.
Dame Evelyn Glennie (39:59):
You know, the brain is an extraordinary
thing, and it will re kind ofjig itself in so many different
ways. But it does need time. Itreally needs time.
Amy Martin (40:11):
It also needs courage and freedom to explore,
and Evelyn has cultivated thosequalities in herself, along with
a beautiful sense of play.Despite all of her success and
expertise, she positions herselfas a learner. She greets an
instrument or a piece of musiclike she's greeting a friend.
She doesn't assume anything. Sheasks questions, starts a
(40:34):
conversation.
Dame Evelyn Glennie (40:36):
I'm very thankful just to have a curious
take on things, and I thinkthat's really what it boils down
to. If I'm picking up a, let'ssay, a waterphone or something,
you know, the first thing I'lldo is look at the object. What
is it made of? Is it metal? Isit wood? Is it skin? Is it
ceramic? Is it glass? Is itporcelain? What is it?
Amy Martin (40:56):
A waterphone looks like the mutant offspring of a
pie pan and a hedgehog. It has around base with spiky rods
attached to it, which can bestruck or bowed. The music
you're hearing is from a videoon Evelyn's YouTube channel
called "Waterphoneimprovisation."
Dame Evelyn Glennie (41:15):
I look at the size of it. Is it hand held?
Is it something that you have tosit to play? Is it something
that you stand to play? Is itsomething that you use mallets
to play or sticks to play and soon. So immediately, before I've
even struck something, the wholebody is involved. And how you
can allow the body to be anextension of this object, so
(41:38):
that there's no longer theplayer, the instrument, the
audience, their music, the this,the that. So how is this body,
sort of merging into thisinstrument? And then I'm like a
kid, so I don't go on theinternet and find out how to
(42:02):
play the instrument. I just say,Evelyn, what are you going to do
with this instrument?
(42:24):
So there's no boundaries, noexpectations, nothing.
So we as sound creators aresound artists. You know, we're
painting sound into a space.
(42:54):
So you just sort of begin tothink, oh, yeah, that's a fat
sound, because it's felt throughyour tummy or your lower part.
Oh, that's a much thinner sound,or that's a weak sound, or, oh,
this is as far as I can godynamically without maybe
causing harm to the instrument.These are the different objects
I can use. And bit by bit, youbuild up your kind of color
(43:14):
palette. And so when you'relooking at an instrument and
engaging with that instrument,you're basically finding out all
of the sign colors you possiblycan in the environment that
(43:37):
you're in that that particularinstrument can produce through
the imagination that you haveand that you're willing to
engage with.
(45:12):
And that is that.
Amy Martin (45:16):
Evelyn has become famous as a maker of sounds, but
she says her primary purpose isto teach the world to listen. In
fact, she created a foundationto advance that mission.
Dame Evelyn Glennie (45:29):
Listening is about being in the here and
now. It's about living each dayand taking the time to
experience what is right infront of you. So it's kind of
stripping down all of thecomplications, releasing all of
the baggage that's on ourshoulders, all of the
expectations. It is just simplybeing and that's very
(45:51):
liberating.
Amy Martin (45:56):
I wanted to expand the boundaries of my own
listening abilities and see if Icould tap into the secret
treehopper communication channelthat Rex had told me about. So I
bought a small contactmicrophone and attached it to
some plants, a lot of plants,and mostly I heard wind and
plant stems bumping into eachother. But I got better with
(46:20):
practice, and one day in a parkin Iowa City, the magic
happened.
I couldn't see who was makingthis noise or where it was, but
somebody was talking and kind ofhumming. I sent this recording
(46:48):
to Rex Cocroft, and he said itwas definitely something in the
cicada group, probably aleafhopper, but he couldn't say
for sure which one. He said itwasn't a sound he had recorded,
and chances were no one else hadheard or recorded it either,
which felt pretty extraordinary.It's not very often that I can
say I might have recorded asound that no other human has
(47:11):
ever heard, and now you've heardit too.
We don't know what it's like tobe a treehopper hearing or hear
feeling the call of anothertreehopper through a plant. Just
(47:32):
like with the dolphins, we can'tget inside their experience. We
can get closer to guessing whatour fellow humans are
experiencing, but even then, wecan't really know. Some people
feel vibrations verysensitively. Other people hear a
huge range of airborne sound, ornone at all, and whatever we're
(47:57):
hearing and feeling right now,that experience is bound to
change over time, often in wayswe can't control. Sound is
ephemeral and ever changing, andso is our experience of it. So
you know that Christmas carolthat asks, do you hear what I
hear? Well, now I know that theanswer is probably, no, I don't.
(48:22):
Or maybe kind of sometimes? butthat difference is actually what
connects us. No one person oreven one species can hear
everything, but together, we area planetary ensemble of
listeners, each of us making ourown entirely unique
contributions, the treehoppersand the spiders, the dolphins
(48:45):
and the percussionists, thecorals and the fishes and you
and me.
This episode of Threshold waswritten, reported and produced
(49:06):
by me, Amy Martin, with helpfrom Erika Janik and Sam Moore.
Music by Todd Sickafoose, postproduction by Alan Douches. Fact
checking by Sam Moore. Specialthanks to Stephanie King for
some of the dolphin sounds youheard in this episode, to Rex
Cocroft for the use of histreehopper recordings, and to
(49:26):
Evelyn Glennie for the use ofher music. I highly recommend
that you check out Evelyn'sYouTube channel and watch her do
the waterphone improvisation weplayed or any of her other
videos there. Just search forDame Evelyn Glennie on YouTube,
or you can find a link on ourwebsite or in the show notes.
(49:46):
Threshold is made by AuricleProductions, a non profit
organization powered by listenerdonations. Deneen Weiske is our
Executive Director. Learn moreat thresholdpodcast.org.
If you stand in front of a classroom full of
(00:01):
kindergarteners and ask themwhat an ear is, chances are good
that they'll think you're kindof silly. Everybody knows what
ears are, those floppy things onthe sides of our heads, the
things we hear with but what ifyou were to pose that same
question to a classroom full ofspiders?
Dr. Natasha Mhatre (00:22):
So this is going into the fun part of my
Amy Martin (00:25):
Dr Natasha Mhatre researches how insects and
research.
spiders process sound at theUniversity of Western Ontario,
and she says that scientistsused to think that spiders
couldn't hear airborne soundbecause they didn't seem to have
any obvious ear like structures.
Dr. Natasha Mhatre (00:43):
That used to be the received wisdom. There's
now different pieces of evidencefrom other labs, including some
evidence we've just collectedthat suggest that they can hear
airborne sound.
Amy Martin (00:53):
Where would their ears be?
Dr. Natasha Mhatre (00:55):
So that's the big question.
Amy Martin (00:58):
Natasha says she and other researchers are now coming
to understand that it's notnecessarily that spiders don't
have ears. They might just lookreally different than ours.
Dr. Natasha Mhatre (01:10):
Okay, so there's some evidence that one
of the ways that they hear iswhen air hits the web of some
spiders, it makes the web move,and they can sense the vibration
of the web, so they're kind ofmaking their own ear drum.
Amy Martin (01:24):
The web is the ear.
Dr. Natasha Mhatre (01:25):
The web is the ear.
Amy Martin (01:27):
How cool is that?
Dr. Natasha Mhatre (01:28):
That is pretty neat, because you can
make whatever ear you want,right? If it gets damaged, you
can just make yourself a newear. Really cool.
Amy Martin (01:40):
Welcome to Threshold, I'm Amy Martin, and
we're going to hear a lot morefrom Natasha in our next
episode. But I wanted to startout with this fun little factoid
about spiders just to shake upour perceptual framework. We
think we know what ears are. Wethink we know what it means to
listen, but those ideas areusually just drawn out of our
(02:02):
own very limited experience. Andspeaking of things we think we
know but maybe don't, what issound? Like, if you had to
define it right now withoutlooking anything up, what would
you say? Even though I work inaudio, I didn't really have a
(02:22):
clear answer to that questionbefore making this season of our
show. Sound is one of thosethings that's so much a part of
my everyday life that it's easyto forget how mysterious it
really is. It's everywhere, butit's invisible. It's flowing
into my brain every wakingmoment and when I'm asleep it
turns out, affecting my mood, myenergy level, my sense of
(02:45):
connection to wherever I am andwhoever I'm with. But what is it
actually? The answer to thatquestion is not as
straightforward as you mightexpect, so in this episode,
we're going to press pause onour timeline of listening to
examine the nature of sounditself, what it is, how it
(03:06):
moves, and how wildly differentour experiences of it can be.
We're going to tap into a secretcommunication network happening
all around us, pay another visitto the dolphins of Shark Bay and
talk to a world famous composerabout how much more there is to
listening than what meets theear.
(03:57):
I'm walking through a Montanaforest. The breeze is rustling
through the trees. There's acreek flowing nearby, and one of
my favorite birds is unleashingits song again and again. It's a
Swainson's thrush, and I loveits song. I think it sounds like
a waterfall flowing up. Chancesare good that you have a bird
(04:21):
song you love too, and even ifyou don't, almost all of us hear
birds singing every day. So in away, this experience I'm having
is completely ordinary. But if Izoom out a bit and think about
what's actually happening here,it's kind of marvelous.
Something that originates insidethe body of a small bird hidden
(04:43):
in the branches above me istraveling across the forest and
landing inside my ears andultimately in my mind, where it
becomes this beautiful, melodicthing with the power to change
my mood and lift my spirits. I'mreceiving something from this
thrush, something is beingtransferred between us, and it's
(05:05):
affecting me. But what is thatsomething exactly? What is
sound?
Dr. Lily Wang (05:11):
So at its heart it is an energy in the form of
vibrational waves in matter.
Amy Martin (05:18):
Dr Lily Wang is an engineer who teaches and studies
acoustics at the University ofNebraska in Lincoln. She fell in
love with sound as a child theway many people do: through
music.
Dr. Lily Wang (05:30):
I love singing. I have loved singing since I was a
little girl, and I've alwaysbeen in choirs, and then I did
also play piano.
Amy Martin (05:39):
I asked Lily to give me a crash course in the
fundamentals of sound, and shestarted with the fact that
there's a wide range of soundwaves, and we can only hear a
portion of them.
Dr. Lily Wang (05:49):
We call it the audible range. The most common
definition of the audible rangeis 20 hertz to 20,000 hertz.
Amy Martin (05:57):
To help make those numbers mean something, here's a
tone moving across that wholerange. It takes about 30
seconds.
(06:29):
But this so called audible rangeshould really be called the
human audible range. Elephants,pigeons and many other animals
can hear well below what we candetect, that's called infrasound
and all sorts of other creaturescan hear way higher than we can
in the ultrasound range. Dogscan pick up frequencies twice as
(06:50):
high as our upper limit. Catscan hear four times higher. And
many dolphins can hear seven oreight times higher than us, up
to 150,000 hertz. That's higherthan almost all other
vertebrates on the planet,except bats. Again, humans top
out at around 20,000 hertz, orfor many of us, significantly
(07:12):
lower.
Dr. Lily Wang (07:13):
I really can't hear above 8,000 hertz anymore.
You know, there are bats in myhouse at certain times of the
year, and I cannot hear them.Like I can see my children go...
woo!..they twist their headslike they can hear that the bats
are back and they're nesting,sadly, in our house, and they're
like, squeaking, but it's atlike, it's probably at like, 10,
(07:36):
12,000, hertz. I do not hear itat all.
Amy Martin (07:39):
Here's what 10,000 hertz sounds like. If you're not
hearing anything, don't worry.You are definitely not alone.
Dr. Lily Wang (07:48):
It's the most common disability among humans
is that we lose hearing and mostoften at that higher frequency.
Amy Martin (07:56):
In fact, some amount of hearing loss is almost
inevitable as we age and ofcourse, some people don't hear
any airborne sound at all. We'regoing to talk to one of those
people later in this episode,but Lily says this measurement
of how we hear sound wavesmoving through the air is really
just one relatively narrowdimension of our lived
experience of sound. All kindsof other factors affect our
(08:19):
listening experience, thetemperature and humidity of the
air, what other sounds arehappening at the same time, the
shape and texture of the spacewe're in, and that includes the
most intimate space of all, ourown individual bodies.
Dr. Lily Wang (08:34):
The shape of your ear, the shape of your head, the
shape of your body, all thesethings are affecting how that
sound wave approaches you.
Amy Martin (08:42):
This is why our voices sound weird in our own
ears. When we hear ourselves onrecordings, we're actually
experiencing the sound verydifferently when it's coming at
us in the air through a speaker,versus hearing it from inside
the place it's produced, theresonating chambers of our own
bodies.
Dr. Lily Wang (09:00):
The fact that we are part of this experience does
actually morph how that wavegets into our head.
Amy Martin (09:07):
So you and I could be walking right next to each
other listening to the sameSwainson's thrush calling in the
forest, and the differences inthe shapes of our bodies means
we'll be hearing slightlydifferent things. But however
the sound waves are ultimatelyreceived, they all start the
same way, with a vibration.
Dr. Lily Wang (09:28):
Something that is moving, something back and
forth.
Amy Martin (09:32):
From there, a whole lot of things happen one after
the other really, reallyquickly. So let's try to follow
the journey of that Swainson'sthrush song step by step, from
creation to reception. In birds,as with humans, song begins with
breath. This thrush pushes airout of its lungs and through a
(09:56):
special organ called the syrinx.It's set up differently from the
human larynx or voice box, butthe basic concept is the same.
The bird squeezes the musclesaround the syrinx, setting air
molecules into motion, and whenit opens its mouth, that
vibration is then passed throughthe air, molecule to molecule
(10:17):
like a baton.
Dr. Lily Wang (10:19):
It's pushing these particles, which push the
next particles, which push thenext particles.
Amy Martin (10:23):
It's an incredibly fast relay race, moving from the
bird across the forest and intomy ears.
Dr. Lily Wang (10:35):
But once it gets into the ear, it's traveling
down and it eventually hits amembrane that is physically
attached to three of thesmallest bones in your body.
Amy Martin (10:47):
That membrane is called the eardrum, and it is a
lot like the tight, bouncy topof the drums we use to make
music, except it's only about acentimeter wide. That's less
than half an inch, the vibratingmolecules of air hit that drum,
making it shake, and that causesthose teeny, tiny bones called
(11:10):
the ossicles to move, one afterthe other, which shakes a second
membrane...
Dr. Lily Wang (11:18):
...that is then connected to fluid inside the
cochlea.
Amy Martin (11:23):
The cochlea is a fluid-filled tube coiled up like
a snail shell or the world'stiniest cinnamon roll, and when
the vibration that began withthe breath of the bird is
transferred into the cochlea, itsends ripples through the fluid
inside, almost like wavesrolling across a miniature
(11:43):
ocean. And lining the inside ofthe cochlea, swaying in the
fluid, guess what we find?Cilia. Tiny little hairs like
the ones that grow on the bodiesof baby corals. Under a
microscope, they look like seagrasses, flexing and bending as
(12:05):
the waves of sound roll overthem.
And as they move in response tothe sound energy, the cilia
perform one of the greatestmagic tricks in the human body.
They transform this physicalvibration into a spark of
(12:28):
electricity, which then shootsoff to the brain through the
auditory nerve, where we processit as a sound.
Dr. Lily Wang (12:36):
And all this happens so fast, like, so fast,
like, in an instant!
Amy Martin (12:41):
343 meters per second, give or take, that's
more than three football fieldsin the snap of a finger.
Dr. Lily Wang (12:48):
So quickly. It's just miraculous.
Amy Martin (12:54):
So to recap the process, the vibration starts in
the body of the bird. Thatenergy is passed across the
forest into my ear canals, whereit hits the drum that moves the
bones that hit the other drumthat shakes the fluid, which
bends the cilia that turn thevibration into electricity that
goes to my brain, in less than asecond. And that's the
(13:18):
simplified version, but asquickly as this vibration is
transferred from the bird to meas I walk through the forest,
the movement of sound and air isactually relatively slow. Sound
moves more than four timesfaster in water compared to the
air.
Dr. Stephanie King (13:36):
This, this.
Laura Palmer (13:38):
This is what we do.
Dr. Stephanie King (13:39):
This is it. This is paradise.
Amy Martin (13:42):
We'll have more after this short break.
Welcome back to Threshold, I'mAmy Martin, and I'm in Shark
Bay, Western Australia, scanningthe horizon for dolphins.
(14:06):
I keep seeing something way outthere.
Dr. Stephanie King (14:08):
Yeah, that was another dolphin. Yeah, yeah.
Amy Martin (14:11):
That's Stephanie King, co-director of Shark Bay
Dolphin Research.
Dr. Stephanie King (14:15):
So we're approaching what we call glass.
There's hardly any wind, andthen you really see how many
dolphins there are in Shark Bay,because you just start to see
them everywhere.
Amy Martin (14:23):
So cool.
In our first episode, we metStephanie and her field team and
a few of the two or 3000dolphins that live in these
waters. Now it's the afternoonof that same day. The heat is
upon us, the wind has died down,and we're moving slowly across
the water.
It's the most beautiful, blue,green water, it's just perfect.
(14:49):
Up ahead, a small group ofdolphins is gathered at the
surface. They're not swimming orjumping. They're just kind of
hanging out there in the calm,quiet waters. Stephanie explains
what's going on.
Dr. Stephanie King (15:02):
You'll sometimes see dolphins in Shark
Bay, what we call snagging. Thisis when they're resting at the
surface, so the whole body'sjust flat on the surface. And it
was because in Australia, yousnag sausages on the barbie,
like snagging. They're calledsnaggers on the barbie, and it
looks just like a sausage lyingat the surface.
Amy Martin (15:20):
But these floating sausages are actually much more
active than they appear. Adolphin doesn't lose
consciousness when it rests, orat least not all the way. Half
of its brain remains engaged inthe work of breathing, which it
needs to come to the surface todo, and stays alert to what's
happening around it, and thatmeans listening.
(15:46):
Researcher Laura Palmer flips onthe speaker in the boat
connected to the underwatermicrophones, and we're suddenly
dropped into a conversation.
These are echolocation buzzes,pulses of sound that the
(16:07):
dolphins send out in order togather information about their
world.
Dr. Stephanie King (16:13):
They wait for the returning echo, and so
the closer they get to a fish,the more they are echolocating
so they can use their returningecho to work out distance and
shape.
Amy Martin (16:24):
It's remarkable to be able to listen in as the
dolphins do this, but it wouldbe even more mind blowing to
experience these sounds the waythey do. Dolphins aren't only
detecting a much wider range ofsounds than we do, the whole
nature of their sonic experienceis something we can only sort of
guess at. These echolocationbuzzes are beams of acoustic
(16:50):
attention, and they come back tothe dolphins packed full of
information that their brainshave evolved to process at
lightning speed.
So what sounds to us like acontinuous buzz, to them, it's
like really fast echo locatinghappening?
Dr. Stephanie King (17:07):
Exactly. Really, really fast clicks. So
they're like pulsedvocalizations, and they produce
them so rapidly, so sometimes itsounds like it's almost a
continuous vocalization.
Amy Martin (17:21):
Dolphins can actually use echolocation to
perceive the insides of objects.If I jumped in the water with
this group, they'd be able tosense not just my outer
surfaces, but my bones andlungs. They would perceive me in
a way I could never perceivemyself, and they'd be doing it
using sound.
Dr. Stephanie King (17:43):
Here we go, snaggers.
Amy Martin (17:45):
We've come upon another group of resting
dolphins.
Dr. Stephanie King (17:48):
Snagging, see. Just resting at that
surface, like a...
Amy Martin (17:52):
Sausage on the barbie.
Dr. Stephanie King (17:53):
Sausage on the barbecue. Exactly.
Amy Martin (17:59):
Stephanie says dolphins use echolocation
primarily to help them find foodand for navigation. But even
now, when they appear to bedoing little to nothing, there
is some echolocating going on.It's like they're casually
scanning the environment, justkeeping the ear out, except that
ear isn't where we might expectit to be on their bodies.
Dr. Stephanie King (18:20):
They receive sound through the lower jaw, and
that sound then goes up to themiddle and in the ear. So when
they're snagging like that andresting, you sometimes see them
their lower jaw is still in thewater, and they're kind of
moving their head side to side,as if they're scanning, right?
They're not vocalizing. They'reactually listening for sounds of
other dolphins, if you like. Sowe typically see that when maybe
(18:42):
they're waiting for a dolphin tocatch up, or there's about to be
a join, and they'll turn aroundand they're scanning, and
they've obviously detectedsomething, and then they're
having a good listen to see whomight be close by.
Amy Martin (18:51):
But with dolphins and other animals that live in
the water, the whole idea ofclose by has to be redefined.
Acoustic vibrations don't onlyhappen faster underwater than in
air, they also do a better jobof holding on to their power as
(19:13):
the vibration is transferredfrom molecule to molecule, it
doesn't lose as much energy witheach pass of the baton, and that
means underwater sounds can stayloud for a much longer time. So
what feels very far away inhuman terrestrial life might
feel quite nearby to a fish or aseal or a dolphin.
Laura Palmer (19:36):
And Rockette just surfaced 80 degrees.
Amy Martin (19:41):
There's a little flurry of extra buzzing from the
group as a dolphin namedRockette pops up and joins them,
but there's no visible change inthe dolphins' faces. It's not
like they're opening theirmouths to echolocate. I asked
Stephanie how they are producingthese sounds, and she says, as
with our vocalizations, itbegins with air pushing through
(20:03):
tissues in the dolphins' bodies.
Dr. Stephanie King (20:05):
They basically have these phonic
lips, these two lips they canpush together and then force air
through that then causesvibrations of different tissues
within that chamber. And it'sthe tissue vibration which
creates the sound, essentially.
Amy Martin (20:21):
I love how they're performing, right on cue, as
you're talking about it, theystarted doing it.
Dr. Stephanie King (20:25):
Yeah!
Amy Martin (20:27):
That vibration then passes through a pillow of fatty
tissue in their foreheads calledthe melon. It acts as a sort of
acoustic lens, focusing andamplifying the sound, which is
then project it out throughtheir heads. We think of making
sound as one thing and receivingit as another, but one of the
(20:49):
things I find most intriguingabout echolocation is that it's
both at once. It's a way ofmaking sound in order to listen.
It takes the whole idea ofactive listening to a completely
different level. Dolphins candecide to shoot a beam of
listening toward another dolphinor an approaching fish, kind of
(21:09):
like the way we might flip on aflashlight in order to see into
a dark corner of a room. Andthey can manipulate that
echolocation beam, they can makeit stronger or weaker, wider or
narrower, and if somethingattracts their attention, they
can turn up the dialinstantaneously and send out a
(21:32):
bright, strong pulse of acousticenergy homing in on whatever it
is they want to investigate.That's what seems to have
happened with Rockette, becauseshe suddenly left her group and
zoomed right under our boat.
Dr. Stephanie King (21:47):
There we go, Rockette in the bow. Hi,
Rockette!
Amy Martin (21:51):
Oh, hi. Hey, beauty. Oh, right underneath us. Oh, my
gosh. I mean I can reach out myhand and touch her. Wow.
It's not us she's curious aboutit's a patch of sea grass below
us in the crystal clear water,we can see her twisting and
(22:13):
turning herself through it.
Dr. Stephanie King (22:15):
So we saw Rockette just come up and rub
herself in a sea grass patch.And we see that a lot with the
dolphins, and we'll call itseagrass play. Or they seem to
come up and drape it over theirbody and even rub themselves
against it, I think just becauseit feels nice. But you see that
quite often. And she obviouslypeeled off from the group,
spotted that seagrass patch andwent over there and started
(22:36):
rubbing herself underneath itbefore returning to the group.
Amy Martin (22:38):
It looked a little bit like a dog growing on a mat.
Dr. Stephanie King (22:42):
Yeah, exactly, and you know, they do
that. It's fun. They enjoy. Itfeels good. Same for the
dolphins.
Amy Martin (22:52):
Lots of animals use echolocation, orcas and sperm
whales, some small burrowingland mammals, and, of course,
the most famous echolocators ofall, bats. The common
denominator here is darkness,where vision is diminished, the
clicks, chirps and buzzes ofecholocation can help animals
(23:13):
navigate their worlds, andhumans can learn to echolocate
too. Many people with visualdisabilities become experts in
it, but even the most highlyskilled person can't come close
to what dolphins can do.
(23:37):
Echolocation is only one of theways dolphins use sound in
future episodes, we'll be comingback to Shark Bay to listen to
their whistles and pops, soundsthey use to communicate with
each other and even to identifythemselves. But now it's time
for us to return to theterrestrial realm, to meet these
mysterious creatures that areusing sound in yet another
(24:00):
fascinating way. We'll have moreafter this short break.
Matt Hurley (24:18):
Hi, my name is Matt Hurley, and I've been a
Threshold listener and donorsince season one came out in
2017. I was also one of thefirst volunteer board members of
the nonprofit organization thatmakes Threshold. Over the past
seven plus years, I've had thisunique first hand look at just
how much work it takes to makethis kind of show. I mean, the
the time, the dedication, thedetermination that's required to
(24:39):
tell these, in depth storiesreally make people think and
feel, and give people a sense ofwhat it's like to really go to
places where the stories arehappening, to talk to the people
who are part of them. It createsthis rich, immersive listening
experience. And it's like thatkind of reporting, this whole
kind of show, is not easy tomake. It's also not easy to
fund. Talk about slow, in-depth,thorough. These are not often
(25:01):
part of the existing models formaking a podcast. So it's up to
people like us to really makesure Threshold can get made. I
believe what Threshold is doingreally matters, and if you do
too, help them keep doing it.Threshold's year end fundraising
campaign is happening right nowthrough December 31 and each
gift will be doubled throughNewsMatch. So if you give $25
(25:22):
they'll receive 50. You can makeyour one time or monthly
donation online atthresholdpodcast.org. Just click
the donate button and give whatyou can. Thank you.
Amy Martin (25:39):
Hi Threshold listeners. Do you ever find
yourself wondering whatbusinesses are doing and what
more they should do to confrontclimate change? Then you should
check out Climate Rising, theaward winning podcast from
Harvard Business School. ClimateRising gives you a behind the
scenes look at how top businessleaders are taking on the
challenge of climate change. Theshow covers cutting edge
(26:02):
solutions, from leveraging AIand carbon markets to sharing
stories that inspire climateaction. Recent episodes feature
insightful conversations withleaders like Netflix's first
sustainability officer, EmmaStewart, who discusses how the
global entertainment giant usesits platform to promote climate
awareness. You'll also hear fromCNN's chief climate
(26:24):
correspondent, Bill Weir, aboutthe importance of integrating
climate change into newscoverage. Each episode dives
deep into the challenges andopportunities that climate
change presents to entrepreneursand innovators. Listen to
Climate Rising every otherWednesday on Apple podcasts,
Spotify, or wherever you getyour podcasts.
Dallas Taylor (26:49):
I'm Dallas Taylor, host of 20,000 Hertz, a
podcast that reveals the untoldstories behind the sounds of our
world. We've uncovered theincredible intelligence of
talking parrots.
Unknown (27:01):
Basically, bird brain was a pejorative term, and here
I had this bird that was doingthe same types of tasks the
primates.
Dallas Taylor (27:10):
We've investigated the bonding power
of music.
Unknown (27:12):
There's an intimacy there in communicating through
the medium of music that can bereally a powerful force for
bringing people together.
Dallas Taylor (27:22):
We've explored the subtle nuances of the human
voice.
Unknown (27:25):
We have to remember that humans, over many hundreds
of thousands of years ofevolution, have become extremely
attuned to the sounds of eachother's voices.
Dallas Taylor (27:33):
And we've revealed why a famous composer
wrote a piece made entirely ofsilence.
Unknown (27:38):
I think that's a really potentially quite useful and
quite profound experience tohave.
Dallas Taylor (27:43):
Subscribe to 20,000 Hertz right here in your
podcast player. I'll meet youthere.
Dr. Rex Cocroft (27:55):
So now we're hearing their mating signals.
Amy Martin (28:00):
Welcome back to Threshold, I'm Amy Martin, and
we're back in the United Statesnow with Dr Rex Cocroft and a
group of wild animals. I'm notgoing to tell you what they are
right away, just listen andguess.
Dr. Rex Cocroft (28:16):
Two or three different males.
Amy Martin (28:17):
So cool.
Here's a hint. These animals aremuch, much, much smaller than
dolphins. They live all over theworld, and millions of people
walk by them every day as theymake these sounds. But we don't
hear a thing. This sound is madeby a treehopper, a teeny little
(28:43):
insect about the size of asunflower seed without the
shell. It communicates byshaking its abdomen, which sends
waves of vibrations through itslegs and out into the stems and
leaves of plants. Other treehoppers can feel those
vibrations with their legs, andthey often respond with their
own belly shakes.
Dr. Rex Cocroft (29:03):
And it doesn't look like they're doing anything
at all. There's stationary. Ifyou're really close, you can see
their abdomen moving when theysignal. But otherwise it just
looks like like nothing ishappening.
Amy Martin (29:15):
And ordinarily it also doesn't sound like anything
is happening. These treehoppercalls don't get broadcast out
into the open air. It's not justthat these insects are small and
their calls are quiet. Thevibrations they make don't leave
the body of the plant. We'reonly able to hear them now
because Rex has hooked up aspecial microphone to the plants
(29:38):
and connected it to somespeakers.
Dr. Rex Cocroft (29:41):
If I turn the speaker down, you don't hear
anything. And we're standingright next to this plant, and
you could put your ears rightnext to me, you really don't
hear anything.
Amy Martin (29:49):
So these little insects are talking to each
other through a secret world ofsound called the vibroscape.
Instead of air or water, theseacoustic waves are moving
through the bodies of livingplants.
Dr. Rex Cocroft (30:03):
It's like they take a different train, sec
through acoustic space and puttogether sound in ways that we
never thought to do.
Amy Martin (30:12):
So what is going on here? How is it possible that
these sounds are happening allaround us, but we can't hear
them? and how did Rex break thecode? Well, it helps that he had
an early interest in music likeLily Wang, and later he combined
that with a love of biology andanimal communication. He studied
(30:35):
frogs at first, but one day inthe 1990s, Rex decided to find
out if treehoppers had anythingto say.
Dr. Rex Cocroft (30:43):
I just walked out onto a meadow near where I
lived. I was at Cornell, so thiswas upstate New York, very
beautiful place in the summer. Ihad a tape recorder. It was a
cassette tape recorder andheadphones.
Amy Martin (30:57):
He found a goldenrod plant with some tree hoppers on
it, and leaned a microphoneright up against it.
Dr. Rex Cocroft (31:04):
And immediately I heard these wonderful sounds.
I'd never heard it before, thistiny insect, this beautiful
song. And then I was hooked. Inever looked back. It was a
sound that I was completelyunfamiliar with, and I could be
(31:26):
confident that no human had everheard that sound before, and
that's still true with most,most insects that communicate
through plants. You listen tothem, and probably nobody's ever
heard that sound before.
Amy Martin (31:42):
And that's basically just because we haven't been
listening. We couldn't hearanything, so we thought there
was nothing to hear.
It's almost like the treehoppersturn the plants and their own
bodies into musical instruments.That's partly what captivated
(32:04):
Rex about these sounds the firsttime he heard them.
Dr. Rex Cocroft (32:07):
To me, it was totally different when I
expected, because it had, it waslike harmonically structured,
and it was changing in pitch,and it was very exciting.
Amy Martin (32:18):
Before we knew anything about their sonic
lives, treehoppers had attractedattention because of their
appearance.
Dr. Rex Cocroft (32:24):
They look like miniature cicadas, and they have
a kind of roof over their backthat in many cases, is very
elaborate and whose function westill don't really know in many
cases.
Amy Martin (32:37):
The treehoppers that Rex studies the most are called
thorn bugs, and they look likerose thorns that can walk. Other
tree hoppers look like they havesand castles on their heads or
bird droppings.
Dr. Rex Cocroft (32:49):
Others have what looks like a little
Starship Enterprise in theirback, a lot of interesting
forms, and others, it's just asmooth roof.
Amy Martin (32:57):
So treehoppers are kind of the quirky rock stars of
the insect world pushing theboundaries of fashion and sound.
This next one might be myfavorite. Its scientific name is
potnia brevicornis, but I thinkof it as Rage Against the
Machine.
Again, this hidden world ofacoustic signaling is called the
(33:26):
vibroscape, and I love thatterm, but it also made me
wonder, since waves of vibrationare happening anywhere there's
sound, isn't the vibroscape sortof everywhere? I put the
question to Rex.
Is there a sharply defined linebetween a sound and a vibration?
(33:47):
Because my understanding is thatall sounds are vibrations. So
why aren't all vibrationssounds?
Dr. Rex Cocroft (33:53):
They're very closely connected, and it
depends on the sensorystructures that you use to pick
them up and how your nervoussystem then relays that
information to your brain.
Amy Martin (34:04):
We can experiment on ourselves in real time to
understand this. If you'replaying this episode through a
speaker in your house or yourcar right now, and you crank up
the volume, you might be able tofeel the music vibrating the
floor or the steering wheel. Ifyou're a person who hears
airborne sound, you can alsohear those waves as they hit
(34:27):
your eardrums. The waves ofvibration have the same source,
the music, but they can beperceived through two different
sensory systems.
Dr. Rex Cocroft (34:36):
It's all the same thing. It's all mechanical
energy that's propagatingthrough an environment, whether
it's a structure, whether it'sthe air, whether it's the water,
but you have to have a differentkind of sensor to pick it up. So
for us, our vibration sensorsare totally different from our
ears and the information fromthose we feel it different. It
(35:00):
goes to different parts of ourbrain, and so that's what makes
it so different.
Amy Martin (35:04):
For us.
Dr. Rex Cocroft (35:05):
For us, right. For us.
Amy Martin (35:11):
Our experience of these two waves of vibration is
bifurcated into two differentsensory systems, hearing and
touch, but that's just areflection of the way our bodies
happen to be put together.
Dr. Rex Cocroft (35:24):
For other animals, they may be just two
sides of the same coin, like theones that I study, these insects
with their six legs, and theyhave vibration sensors in their
legs, but some of thosevibration sensors also act as
pickups for airborne sound. AndI don't honestly know how they
tell the difference sometimes.How do they know if it's a sound
(35:46):
or a vibration, if they'repicking it up through their
legs? And I'm not really surethe answer to that.
Amy Martin (35:55):
Or maybe the whole question of what defines sound
versus vibration only makessense from within our own
perceptual framework. Maybe ifyour senses of touch and hearing
are more unified, there is nodifferentiation, really.
Dame Evelyn Glennie (36:10):
We're actually incredibly gifted
listeners. You know that isinherent to being a human being.
We have the capacity to listen.I think it's a categorization of
the word "listen" that getsreally confused.
Amy Martin (36:25):
Dame Evelyn Glennie is a world renowned
percussionist and composer.She's also deaf. She doesn't
hear airborne sound waves, butshe says listening is available
to everyone.
Dame Evelyn Glennie (36:39):
You know, we think about hearing, and
Amy Martin (36:39):
Evelyn grew up in rural northern Scotland, helping
that's something that can bemeasured. That's something that,
out on her family's farm, andshe says the patience that
you know, medically, we can seewhether that person can hear a
certain frequency at a certainvolume. However, listening is
farming requires gave her someof her first formative lessons
not something that can bemeasured medically. Someone can
be born deaf, but they can beamazing listeners.
(37:10):
in listening.
Dame Evelyn Glennie (37:11):
Because listening is all about patience
that I have learned over time.So you can't force a field to
grow corn any quicker than itwill grow the corn according to
the season and the weather. Youknow, you can't dictate when a
sheep will give birth to a lamb.It will just naturally give
birth to a lamb as and when thattime is right. You know, there
(37:33):
are certain things that justneed to happen naturally. And so
I think that is very much to dowith listening. You know, is
that we can control a certainamount, but ultimately, we also
have to work in partnership withthe existence that we're in,
with the environment that we'rein.
Amy Martin (37:53):
Evelyn had already exhibited a strong interest in
and talent for music when shebegan to lose her hearing around
the age of eight.
Dame Evelyn Glennie (38:02):
I realized that one aspect of the body was
no longer working as it used towork.
Amy Martin (38:09):
But this change did not stop her development as a
musician. In fact, it seems tohave enhanced it. When she began
studying percussion at age 12,her teacher suggested she take
out her hearing aids and tuneinto other ways of sensing the
music. That's when she startedto learn how to listen with her
whole body, to pay attention tothe vibe escape.
Dame Evelyn Glennie (38:33):
It's simply the knowledge that sound is
vibration, that is what soundis, and therefore our bodies are
a resonating chamber. So if I'mplaying a glockenspiel or cymbal
or triangle or anything withhigh frequencies, it's more than
likely going to touch the faceand the upper part of the body.
(38:54):
However, with low, low sounds,such as playing bass drum or
timpani, or anything with areally low, resonant sound.
Obviously the vibration is quitewider and bigger, and that will
reach a larger part of yourlower part of the body. So you
know, your tummy, your chest,down your legs, your feet,
through the stage and so on.
Amy Martin (39:16):
Evelyn has developed her ability to feel differences
in pitch, tone and musical colorat a much subtler level than
most people, and used thoseskills to become one of the most
celebrated percussionists of alltime. She composes for the
concert hall, for films and fortelevision, and she performs all
(39:36):
over the world. She's wonmultiple Grammy Awards, the
Polar Prize, and a long list ofother honors. Clearly, she has a
musical force in her that wasnot going to be denied no matter
what. But even though we're notall going to become musicians of
Evelyn's caliber, she insistsanyone can learn to sense sound
(39:57):
as a whole body experience.
Dame Evelyn Glennie (39:59):
You know, the brain is an extraordinary
thing, and it will re kind ofjig itself in so many different
ways. But it does need time. Itreally needs time.
Amy Martin (40:11):
It also needs courage and freedom to explore,
and Evelyn has cultivated thosequalities in herself, along with
a beautiful sense of play.Despite all of her success and
expertise, she positions herselfas a learner. She greets an
instrument or a piece of musiclike she's greeting a friend.
She doesn't assume anything. Sheasks questions, starts a
(40:34):
conversation.
Dame Evelyn Glennie (40:36):
I'm very thankful just to have a curious
take on things, and I thinkthat's really what it boils down
to. If I'm picking up a, let'ssay, a waterphone or something,
you know, the first thing I'lldo is look at the object. What
is it made of? Is it metal? Isit wood? Is it skin? Is it
ceramic? Is it glass? Is itporcelain? What is it?
Amy Martin (40:56):
A waterphone looks like the mutant offspring of a
pie pan and a hedgehog. It has around base with spiky rods
attached to it, which can bestruck or bowed. The music
you're hearing is from a videoon Evelyn's YouTube channel
called "Waterphoneimprovisation."
Dame Evelyn Glennie (41:15):
I look at the size of it. Is it hand held?
Is it something that you have tosit to play? Is it something
that you stand to play? Is itsomething that you use mallets
to play or sticks to play and soon. So immediately, before I've
even struck something, the wholebody is involved. And how you
can allow the body to be anextension of this object, so
(41:38):
that there's no longer theplayer, the instrument, the
audience, their music, the this,the that. So how is this body,
sort of merging into thisinstrument? And then I'm like a
kid, so I don't go on theinternet and find out how to
(42:02):
play the instrument. I just say,Evelyn, what are you going to do
with this instrument?
(42:24):
So there's no boundaries, noexpectations, nothing.
So we as sound creators aresound artists. You know, we're
painting sound into a space.
(42:54):
So you just sort of begin tothink, oh, yeah, that's a fat
sound, because it's felt throughyour tummy or your lower part.
Oh, that's a much thinner sound,or that's a weak sound, or, oh,
this is as far as I can godynamically without maybe
causing harm to the instrument.These are the different objects
I can use. And bit by bit, youbuild up your kind of color
(43:14):
palette. And so when you'relooking at an instrument and
engaging with that instrument,you're basically finding out all
of the sign colors you possiblycan in the environment that
(43:37):
you're in that that particularinstrument can produce through
the imagination that you haveand that you're willing to
engage with.
(45:12):
And that is that.
Amy Martin (45:16):
Evelyn has become famous as a maker of sounds, but
she says her primary purpose isto teach the world to listen. In
fact, she created a foundationto advance that mission.
Dame Evelyn Glennie (45:29):
Listening is about being in the here and
now. It's about living each dayand taking the time to
experience what is right infront of you. So it's kind of
stripping down all of thecomplications, releasing all of
the baggage that's on ourshoulders, all of the
expectations. It is just simplybeing and that's very
(45:51):
liberating.
Amy Martin (45:56):
I wanted to expand the boundaries of my own
listening abilities and see if Icould tap into the secret
treehopper communication channelthat Rex had told me about. So I
bought a small contactmicrophone and attached it to
some plants, a lot of plants,and mostly I heard wind and
plant stems bumping into eachother. But I got better with
(46:20):
practice, and one day in a parkin Iowa City, the magic
happened.
I couldn't see who was makingthis noise or where it was, but
somebody was talking and kind ofhumming. I sent this recording
(46:48):
to Rex Cocroft, and he said itwas definitely something in the
cicada group, probably aleafhopper, but he couldn't say
for sure which one. He said itwasn't a sound he had recorded,
and chances were no one else hadheard or recorded it either,
which felt pretty extraordinary.It's not very often that I can
say I might have recorded asound that no other human has
(47:11):
ever heard, and now you've heardit too.
We don't know what it's like tobe a treehopper hearing or hear
feeling the call of anothertreehopper through a plant. Just
(47:32):
like with the dolphins, we can'tget inside their experience. We
can get closer to guessing whatour fellow humans are
experiencing, but even then, wecan't really know. Some people
feel vibrations verysensitively. Other people hear a
huge range of airborne sound, ornone at all, and whatever we're
(47:57):
hearing and feeling right now,that experience is bound to
change over time, often in wayswe can't control. Sound is
ephemeral and ever changing, andso is our experience of it. So
you know that Christmas carolthat asks, do you hear what I
hear? Well, now I know that theanswer is probably, no, I don't.
(48:22):
Or maybe kind of sometimes? butthat difference is actually what
connects us. No one person oreven one species can hear
everything, but together, we area planetary ensemble of
listeners, each of us making ourown entirely unique
contributions, the treehoppersand the spiders, the dolphins
(48:45):
and the percussionists, thecorals and the fishes and you
and me.
This episode of Threshold waswritten, reported and produced
(49:06):
by me, Amy Martin, with helpfrom Erika Janik and Sam Moore.
Music by Todd Sickafoose, postproduction by Alan Douches. Fact
checking by Sam Moore. Specialthanks to Stephanie King for
some of the dolphin sounds youheard in this episode, to Rex
Cocroft for the use of histreehopper recordings, and to
(49:26):
Evelyn Glennie for the use ofher music. I highly recommend
that you check out Evelyn'sYouTube channel and watch her do
the waterphone improvisation weplayed or any of her other
videos there. Just search forDame Evelyn Glennie on YouTube,
or you can find a link on ourwebsite or in the show notes.
(49:46):
Threshold is made by AuricleProductions, a non profit
organization powered by listenerdonations. Deneen Weiske is our
Executive Director. Learn moreat thresholdpodcast.org.
Popular Podcasts
24/7 News: The Latest
The latest news in 4 minutes updated every hour, every day.
Therapy Gecko
An unlicensed lizard psychologist travels the universe talking to strangers about absolutely nothing. TO CALL THE GECKO: follow me on https://www.twitch.tv/lyleforever to get a notification for when I am taking calls. I am usually live Mondays, Wednesdays, and Fridays but lately a lot of other times too. I am a gecko.
The Joe Rogan Experience
The official podcast of comedian Joe Rogan.