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Why Did Music Evolve? - 4 Hypotheses | Stefan Milo | YouTubeToText
YouTube Transcript: Why Did Music Evolve? - 4 Hypotheses
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[Stefan] "It seems, it just seems like a very special thing that we do,
I don't know if you agree or disagree with that but... "
[Ed] "Yeah I agree completely. uh Music really stands out as a big mystery.
Everybody loves it, as you say, from infancy through old age, we almost everyone around
the world in all different cultures, we love music. It's a really big part of our lives
and yet how it might contribute to survival and reproduction
is completely mysterious, it doesn't make any sense, it doesn't have any obvious utility".
Music is a human universal, it is absolutely everywhere. You literally
cannot find a single human society that doesn't love it,
doesn't produce it. Its character and origins have long intrigued scholars from ancient times through
to now. The more archaeologists excavate, the further back in time we find evidence of music.
Our archaic stone age cousins might also have rocked out to a funky beat or two but
despite all this there remains one huge unanswered question, why do we do it?
I sat down with professor Ed Hagen to discuss four hypotheses on the origins of our love of rhythm.
This video is sponsored by Curiositystream. Get access to my streaming video service
nebula when you sign up for curiosity stream using the link in the description.
I think where we need to start is that not everything has to
have evolved to have some function and that is
the hypothesis that's commonly known as the auditory cheesecake hypothesis of Steve Pinker.
Humans by and large love cheesecake, love desserts, not because our ancestors evolved
and developed in a cheesecake rich environment but because we love a high calorie diet with
lots of fats and sugars and cheesecake happens to tickle those same senses. Pinker wondered if
the same was true for music. In particular he argued these six senses were tickled by music.
First language, which is of course intimately connected to music in
many, many ways that you're all aware of.
Second, auditory scene analysis. So our ears receive an absolute cacophony of sounds that
the brain has to interpret and analyze to make sense of the chaos around us.
Perhaps music with its string of related harmonies really
satisfies the part of our brain that likes to make sense of a complex sound world.
Third, emotional calls. Perhaps music evokes a strong emotional response in us
because it resembles in some way our instinctual emotional reactions laughter cheering screaming.
Four, habitat selection. Obviously when selecting a home we pay attention to visual
clues of safety like nice light, open views etc but also auditory signals of safety. You
wouldn't like being near howling wind or the roar of a flash flood. Perhaps music signals
the opposite that this is a safe environment? Maybe the rising and falling of musical tones
mimics in some way the rising and falling of natural sounds that we're compelled to listen for.
Five, motor control. Our bodies love rhythm whether it's in running, jumping, playing we love
to move, we love the rhythm of movement. Perhaps music and dance are a concentrated dose of that.
Six, something else, something else that makes music greater than the sum of its parts, some
je ne sais quoi, some special extra ingredient.
[Stefan] Well it does seem like, um as i was saying with my kid, we seem to love it so much for
it to be a byproduct of just other other factors. But saying that we do love cheesecake a lot.
[Ed] Right, right and that's the mystery. um It is a really strong hypothesis
and that's the one we have to beat. I think where Steve, the weakness in in in Steve pinker's idea
is that he really doesn't grapple with what we call comparative evidence which is looking at
similar behaviors in other species that aren't human music but aren't that different either.
So if we just look at vocal communication we see that many, many, many species uh communicate
with very rich complex auditory signals and as we all know a lot
of them kind of do sound like music. Bird song sounds a lot like music.
[Stefan] Do we consider what a bird does music? Is it different to what we do?
[Ed] Yeah, so Steve would say yes, so he would want to define music in a way that excludes
birdsong and of course folks like me would want to define birdsong in a way and music
in a way that includes birdsong. Neither i nor nor anybody else who's kind of working on
sort of adaptive functions for music would claim that bird song is exactly the same
as human music but we'd say there's enough similarities that we can't dismiss the overlap.
Birds don't just produce song for sexual selection, they like to mark their territory and
ward off predators, things like that, but sexual selection is a massive part of birdsong. Could the
same be true for humans? Did we develop music to suggest some sort of sexual fitness on our part?
So this was Darwin's original idea for the evolution. In fact Darwin proposed the first
evolutionary hypothesis for the evolution of human music and it was with an explicit analogy
to birdsong which he and many others biologists even today feel in many species is what we call
sexually selected signal. So all species face the problem of attracting mates. There's often a
process of mate selection that your fitness, your ability to produce viable offspring,
depends on the quality of your mate so there's going to be mate selection that you want to pick
the best mate, and that can apply to females, it can apply to males. can apply to both sexes,
often does. But the question is, how do how does the opposite sex assess
mate quality? And one of the ways, one of the hypotheses for birdsong,
is as exactly as you said, is that it's a sexually selected signal. That producing song
takes a very sophisticated cognitive abilities. It involves precise generation of notes, precise
sequencing. Unfortunately mutations are happening all the time that can interfere with that.
Males, let's say, that are producing high quality songs may be more attractive to females.
Now your question, and so what Darwin proposed is could that be the same that same thing that's
true in humans? It has a lot of face validity, uh we all know that rock stars get the babes.
[Stefan] Yeah it's funny when you mentioned, uh
started talking about sexual selection my mind did immediately jump to Motley Crue.
[Ed] right?
[Stefan] they are like the archetypal like a
definition of that. I'm sure Charles Darwin would have a lot to say about that.
[Ed] Right? I always think of Aerosmith.
[Aerosmith] what did we get ourselves into?
[Ed] We know that, you know, it seems like at least half the songs out there are love
songs and have lots of sexual themes. So I think the sexual selection hypothesis,
at least initially, seems like a really strong one.
But what we see in other species where the case for a sexually selected song is is really strong,
it's males giving the songs to attract females. There's a real sex difference in song production
and in sexually selected signals in general you'll often see the males are the ones giving
off these signals to attract females. So if that were the explanation in humans,
we should really see a lot of sex differences in music abilities, music production and we really
don't. So women are just as accomplished musicians as males, they enjoy music just as much as males
do, they're just as good at it. So there's none of the sex differences that we would expect.
There are other things that suggest our love of music isn't
purely sexual in nature. People of all sorts of different sexualities can enjoy music
by different sexes, there's no correlation there. You'd expect children to make more
music as they went through puberty but that's not true. Children of any age love making music,
parents love singing to their children. So even though sexual selection might have
played some part in the development of music, it's definitely not the only thing going on.
As i'm making this video I'm trying to think about the times I've absolutely loved music,
participating in it, making it all that stuff, and it's got to be when I'm with my mates at
something, especially if we've been drinking. Like probably the time I've most enjoyed music
is drunk at a pub singing, I don't know, 'Fairy Tale of New York' or something.
That's, that's probably sincerely the time I've most enjoyed music. And this idea, that music
sort of bonds us together, it's actually a really popular hypothesis for its origins.
So the social bonding hypothesis is is the most popular hypothesis right now for the evolution of
human music. There isn't one single social bonding hypothesis of music it's an idea that's been
thought about a lot but here is a summary of a popular idea recently expressed in this paper. The
idea works like this, living together in a group has a cost. you're more likely to get diseases,
there's a lot more competition for food, and a lot more competition for mates, but there are
some advantages such as increased protection from predators and cooperative food gathering. In order
to balance the costs and benefits of group living, primates developed mechanisms to encourage bonding
in particular grooming. There's nothing like picking fleas off your uncle to
get rid of some group tension. However, at some point in our evolution this became untenable
because group size kept increasing. Once a group gets larger than say 20 individuals
there just isn't enough time in the day to groom everyone, you'd be doing it forever. So humans
and our ancestors needed another mechanism to encourage bonding hence the evolution of music.
Rhythm harmony and predictability are hypothesized to be the driving force
behind this. As we sing and play music in a group and successfully harmonize
this creates feelings of fulfilled expectations, successful predictions, and mutual accomplishment.
These feelings are of course accompanied by a dopamine hit, importantly this dopamine
hit lasts much longer than the performance of the music and fosters a sense of bonding
between everyone who took part and there is definitely evidence to support this idea.
[Ed] If you just do experiments with people, you take strangers
and you have one group of strangers um do some kind of arbitrary task and you have a second
group you kind of randomize people into different groups, and one group does you know i'm not quite
sure, you know writes an essay or does something, and the other group sings and dances together,
and then you do some psychological measures of how close do you feel to these people.
Indeed the group in the singing group or the dancing group will
kind of have higher ratings on feeling close or friendly or altruistic towards these strangers
so there is some evidence for the social bonding hypothesis.
If you look at this mural behind me, no doubt everyone on it felt close to their fellow
musicians felt close to their band mates, loved performing together really felt like it bonded
them to their fellow musician and I think we all feel that there's something to the social
bonding hypothesis. Music bringing us together, it really is like a universal human experience,
I think that's true. Critics of the hypothesis argue though, firstly
do we actually need to groom each other to be social? Maybe not being eaten by
a lion is enough motivation to hang out with your friends, and secondly,
just because music has this effect on us is that necessarily the initial reason why it evolved
or is that just a happy byproduct? Almost like the auditory cheesecake hypothesis again.
[Ed] and that's exactly, so there's there's there are studies that show
that um petting animals reduces anxiety, that doesn't mean that petting animals evolved
that we evolved to pet animals to reduce our anxiety. So there's all of these you
know causality there's all kinds of complex causal relations in the world,
and almost none of them evolved to have that effect. So we all enjoy petting animals,
it may reduce our anxiety, but that's a very bad explanation for why we like petting animals that
it evolved that we evolved to pet our dogs to reduce our own anxiety. So we probably did not
evolve to sing and dance to feel close to people, even though it does have that effect exactly yeah.
It would be hard to name a musical performance more or inspiring, more spine tingling than the
Maori hakka. Sometimes performed to intimidate enemies, other times to celebrate big occasions,
honored guests, other times a celebration of life, there's no one reason to perform it,
but whatever the occasion one thing's for certain it's a clear display of the prestige,
power and unity of the group performing it. Does the origin of human music, all human music,
lay in a similar desire to display, to signal to those around you whether friend or foe?
So if we look at other species including songbirds and other species, whales, that give off these
complex vocalizations, almost all the theories that evolutionary biologists have proposed are
what we call signaling theories. So there's something, some information
about individual A, or that individual A has, that they benefit by communicating to
the audience, might be one other individual, multiple individuals and that the audience
members also benefit by getting that information. So that's signaling. But the problem that comes up
in any signaling system is the problem of lying or cheating. So males want to mate with females,
so there'd be an incentive to give a false signal of genetic quality. Let's say a male
with a lot of mutations was able to falsely kind of indicate that he was mutation free,
he would get mating benefits but the females would not benefit because their offspring would have
birth defects. So females would evolve to ignore the signal, unless they can trust it,
and that's what we mean by credible signaling,
that's what evolutionary biologists mean by credible, signals that you can't fake.
Auditory signals are almost inherently credible,
you either make a noise, make the correct noise or you don't. One of the most common things animals
want to signal is territorial defense. I'm here i'm willing to defend this spot of land.
The chirps of this squirrel might not intimidate us but they're letting everyone know, "hey
stay off my fence". Another excellent example would be wolf holws. A pack of wolves howling is
inherently a credible signal, it is impossible to fake. If the wolf literally isn't there,
then no howl can be heard. If there's only one lone wolf, it can't pretend to be five or six.
[Ed] ..and we, and there's actually good loudspeaker studies that show this
in both lions and actually chimpanzees have these loud pant hoops that they do together as well,
that show that other potential intruders are listening and they can count. So if you
play one individual or two individuals, they might still approach the speaker,
but if you play three, they don't, they won't do it. So our hypothesis um is that human music
may have evolved from something like wolf howls because we were beginning to move from a more
plant-based diet into a more meat-based diet, we'd be becoming predators ourselves, and so we
may have evolved very much something like a wolf howl to advertise this is our hunting territory.
Although our music now may be extremely different to the signaling calls of wild animals, no one
could deny that signaling, or to phrase it another way performance is an integral part of music.
One implication of this idea is that the origins of human music are really,
really old as old as homo erectus, as old as the australopithecines.
[Stefan] is that how far you would project it back into time?
[Ed] Easily because we see that gibbons, who are also ape,s and we are relatively
close relatives of, gibbons give these very complex music-like vocalizations and they do
it in duets. So highly coordinated note-like sequence of note-like vocalizations yeah.
um so if we're seeing it in gibbons it could potentially even be in the last common ancestor
of humans and chimps or if not then potentially sometime in the evolution of hominins,
in the australopithecines, or early homo absolutely, absolutely. So very deep um
time frame. Now it may have initially been more like you know the chimpanzee pant hoot, not such a
complex vocalization, yeah maybe more like wolf howling and and coyote howling. Um.. so when
it acquired this more complex structure, could have been early, because we see it in gibbons,
could have been a little later, we don't really know.
The credible signaling hypothesis also attempts to explain another very common form of music,
parents singing to children. The idea is that singing a lullaby to a child is a credible
signal because it's impossible to have a conversation really with someone else at
the same time. So if a crying child hears their mother or father singing to them,
they know they have their full attention, more or less, they might be watching tv
but they won't be chatting to someone else. Like sheep really,
like how sheep communicate to their children, like how many animals communicate to their children.
What i really love about the credible signaling hypothesis is that it doesn't put human music on
this pedestal above the vocalizations of all the other animals out there.
It doesn't attempt to explain our behavior separately from theirs, and I always like that,
I always love that approach. Not that we're not unique in many ways but there's so much we can
learn about our behavior and our history through studying our fellow earthlings. So that approach,
it just always resonates with me. Saying that there are elements of truth in all
four of these hypotheses. Music does tickle our senses, we do find it attractive , it certainly
bonds us together and we definitely use it to intimidate our enemies. So I can't, I can't really
uh wrap this video up neatly for you, it's uh just something you're going to have to ponder as you're
singing in the shower, credibly credibly signal to everyone in the shower about what you're doing.
Thanks for watching the video, I hope you enjoyed it, I put a lot of work into it. Finding
the footage of gibbons singing in Laos uh was not easy, but i'm happy to do it, I love to
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So head on over to curiositystream.com/stefanmilo
or click on the link in the description go check it out. I'm thrilled to be a part of it,
hopefully i'll produce some banging exclusives myself in the near future. I certainly hope so.
Huge thanks to professor Ed Hagan for generously sharing his time and his expertise
and huge thanks as always to my patreons for just keeping this whole show taking along. See ya!
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