
Perceptions of musical octaves are learned, not wired in the brain - gpvos
https://www.quantamagazine.org/perceptions-of-musical-octaves-are-learned-not-wired-in-the-brain-20191030/
======
dr_dshiv
I was skeptical of his prior dissonance study. I feel there is a bit of
accommodation by the participants to maximize the surprise of the researcher.
Getting goods for singing funny.

The paradigm I would have liked to see is where two tones are held constant
and the participant moves a third tone to the location that sounds the best or
the worst.

It is remarkable work. But I don't believe it. Octaves are just too basic a
phenomena to be viewed as a cultural invention.

~~~
enriquto
> Octaves are just too basic a phenomena to be viewed as a cultural invention.

Octaves are consonant or dissonant depending on the timbre of the sound. For
sounds produced by harmonic instruments, like a vibrating string or air
vibrating inside a long tube, the sound is a superposition of waves whose
frequencies are integer multiples of a fundamental frequency. Then, playing
two sounds an octave apart will match exactly all these frequencies and it
will sound nice. But there are other instruments (not privileged in the
western music tradition) whose timbre is not composed of integer multiples of
a fundamental frequency; and in these instruments octaves sound very
dissonant.

You can argue that the octave is a "basic phenomenon" inasmuch a vibrating
string is basic. Yet, from the point of view of a person who uses a
synthesizer, the octave has nothing special with respect to other intervals.

~~~
thesz
What are these instruments? I guess their behavior has to be described by some
interesting partial derivatives equations that give rise to non-integer
multiplies harmonics.

So, what are they? I'd like to know.

~~~
TheOtherHobbes
Bells, gongs, drums, and other instruments that can be a modelled with a 2D
surface that vibrates in an assortment of simultaneous modes are semi-
harmonic.

Pipes and strings are better modelled by a 1D resonator, which is more likely
to allow integer overtones - although they can still have inharmonic elements
due to stiffness and - in the case of orchestral strings - rotation caused by
the scraping bow.

None of which changes the fact that octaves are primary in any instrument
which produces a range of pitches with a clear and reasonably sustained
fundamental.

In fact researchers rely on the concept of pitch chroma/pitch class to
distinguish between absolute frequency. Humans reliably hear the octave/not
octave distinction, as do some animals. Obviously the animals aren't musically
trained.

[https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5479468/](https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5479468/)

But it's not enough to say that "octave perceptions are learned." In this
experiment it's more likely that octave _use_ is learned in musical contexts.

There's a huge difference between saying that someone can't hear octave
relationships at all, and that they can hear them perfectly clearly, they just
don't find them culturally relevant - perhaps because their music theory is
built on a grid of absolute pitches, and not on a repeating pattern of
pitches.

~~~
dr_dshiv
Also worthwhile to point out that brainwave coupling is based on "octaves"
(i.e., roughly speaking -- gamma is double frequency of beta, which is double
alpha, which is double theta, which is double delta....)

------
FeepingCreature
This study does not show what the title claims.

Alternate title: Tsimané people do not perceive melodic harmonies.

This is also the case for some non-Tsimané people (google Amusia). There could
just be a genetic basis here.

For comparison, you'd need a Tsimané child raised in Western culture, or
reverse.

~~~
gpvos
They could reproduce the intervals without problem, they just transposed them
by something else than a multiple of octaves. You make an interesting point in
the last sentence though.

~~~
FeepingCreature
My horse in this race is that I know somebody who was raised on western music
and has the same problem. I don't know if it's amusia per se or some related
pathology, but I definitely think it's not just acculturation.

We spent several hours arguing whether music theory was a valid field of study
or complete bunk until we noticed he didn't perceive melodic harmony at all.
It was fun, if exhausting. That person also nailed an amusia test, which makes
me suspect there's a separate condition.

------
dahauns
>The researchers acknowledged in the study that the results might reflect
differences in how people sing, and not in how people perceive pitch. But they
argued that the totality of collected data, including some more direct
measures of octave perception, put the weight of evidence on the side of a
perceptual explanation. [..] Moreover, if the Tsimané’s performance in the
tests has more to do with singing ability than their perceptual experience,
then it would mean that all people have absolute pitch

Since I only have access to the abstract: How did they argue this in detail?
Because that is something that immediately sprung at me. In the process of
learning to sing, reproduction of relative intervals is far easier (and much
earlier) learned than correct absolute positioning °) which actually takes
some effort to train.

And the reasoning in the second paragraph eludes me completely. If I haven't
completely misunderstood something, this has nothing to do with absolute
pitch, and everything with tonal memory, which - again - won't work if it
isn't trained:
[https://en.wikipedia.org/wiki/Tonal_memory](https://en.wikipedia.org/wiki/Tonal_memory)

°) EDIT: Apology, the choice of words is actually incorrect. It's still
relative, but with reference to the notes heard before, in contrast to the
reproduction of intervals where you have your own previous sung note as
(control) reference. Simply put: it's _much_ harder to learn to hit the first
note (and thus the general pitch) of the sequence correctly than the intervals
_in_ the sequence.

------
frodetb
Quite a bold title. My understanding (while limited) is that the human ear
senses sound by means of tiny hairs in the inner ear that vibrate in resonance
with incoming sound waves. I've always believed that the reason certain
intervals are more harmonious to us than others was because there would be
some overlap in hairs that resonated for the different harmonious pitches. The
same way guitar strings will resonate with other strings that are tuned an
octave, or perfect fifth, or fourth higher, these ear-hairs ought to behave by
the same physical laws and principles.

As such, I'm a bit skeptical of the method and conclusion of this research. It
seems like physics to me, not psychology. Ability to reproduce pitches and
intervals does not strike me as entirely related to what they were trying to
find out.

How about instead playing different soundbites, of consonant and dissonant
pitches, and asking for their opinion in some way? Maybe even allowing the
participant to find a relationship by some sliding instrument themself? That
would seem more aimed at studying the Tsimané's ability at "perceiving
octaves."

Maybe my interpretation of the header and conclusion is wrong. Perhaps the
idea is that _some training_ is needed in order to perceive octaves, the same
way _some training_ is needed in order to learn how to walk. That I might be
able to wrap my head around.

------
im3w1l-alt
Music is definitely an acquired taste. My family was not very good at nor into
music. I didn't understand the point of instrumental music until my mid teens.
Before that I only listened for the lyrics.

On a different note, people often think of the octave as the most fundamental
interval, but the most fundamental is the very same tone twice. Even here
people like a little dissonance. Two tones at nearly but not exactly the same
pitch will produce a pleasantly shimmering chorus effect.

Anyway music is subjective and there's is no sound that is better than
everything else in all respects and contexts.

~~~
schwartzworld
I have never heard "out of tune unison" described as an interval, except in a
joke about viola players. Sure, there's a difference between 440 and 442 but
that's not considered an interval in western music theory.

~~~
agency
> Sure, there's a difference between 440 and 442 but that's not considered an
> interval in western music theory.

Well that's just your 2 cents... I mean, 7.85 cents.

------
tunesmith
I wonder if this is more a problem with the article than the study. I haven't
read the study. It feels oddly described. Like, are they saying that when a
Tsimané sings a song (solo, without instruments) on Tuesday, and then later
sings the song on Friday, it's guaranteed to always start on the same pitch,
without hearing some sort of reference note from an instrument? If so, that's
basically perfect pitch.

We all have comfortable vocal ranges, and I know generally where to start the
Star Spangled Banner to hit both the high notes and the low notes, but since I
have relative pitch and not perfect pitch, my starting point is still always
going to vary within a minor third or so.

Incidentally, I noticed in my college ear training courses that I (I have
excellent relative pitch) would routinely score higher than the folks with
perfect pitch. There's something about perfect pitch that can be really
distracting to musicians for certain exercises, as it's not quite as flexible
as relative pitch. So maybe that's related to the Tsimané.

Also, there are _aspects_ of different notes that very much are noticeable in
physical reality and don't need to be culturally learned. In an old singing
group of mine, we would have fun with a game where we would stand really close
to each other, face to face, and sing unison, and then one of us would start
to go slightly sharp or flat while the other would try to stay steady. There's
an ugly "beating" sensation when this happens that goes away when you come
back to unison. It's not just theory, you hear/feel it. That's present to a
lesser extent with octaves, and then fifths, through the harmonic sequence.

Those subtleties are of course covered up when you're using separate
instruments or timbres, but using different timbres doesn't disprove the
underlying presence.

~~~
codezero
Sounds like you were generating a beat frequency, pretty neat :)

[https://en.wikipedia.org/wiki/Beat_(acoustics)](https://en.wikipedia.org/wiki/Beat_\(acoustics\))

------
klysm
I find this hard to believe from a mathematical point of view - octaves are as
far as you can get from arbitrary which is I guess what gives the headline
it’s shock value.

~~~
chrisseaton
What is the reason for there being eight notes (or seven? I don't really
understand it) in an octave?

~~~
smilespray
That's far more arbitrary, and there are plenty of other scales that don't
conform to this.

~~~
chrisseaton
I don't understand - so they are arbitrary? And so arbitrary that people don't
even agree on it?

~~~
sideshowb
The harmonic series (of which the first three intervals are octaves, fifths,
fourths in pythagorean tuning) is not arbitrary.

How you construct a more useful set of notes from the harmonic series is
arbitrary. The 1.5^12 ~= 2^7 coincidence I note above allows you to construct
a scale using octaves and fifths. You can just as easily do it with other
similar coincidences, use fifths and fourths instead, etc etc.

Check the smoothness/roughness functions in my blog link - the reason you
think e.g. a 3rd sounds as 'right' as a 7th is likely purely cultural. Other
cultures have other scales. One of the Indian ragas has over 100 notes.

(I'm aware OP claims it's ALL learned, including the octave, but even if true
I don't think that means it's all cultural).

~~~
divbzero
To elaborate, intervals in the harmonic series are not arbitrary because the
frequencies of the two notes forms a ratio:

    
    
      2:1 octave [1]
      3:2 perfect fifth [2]
      4:3 perfect fourth [3]
    

[1]:
[https://en.wikipedia.org/wiki/Octave](https://en.wikipedia.org/wiki/Octave)

[2]:
[https://en.wikipedia.org/wiki/Perfect_fifth](https://en.wikipedia.org/wiki/Perfect_fifth)

[3]:
[https://en.wikipedia.org/wiki/Perfect_fourth](https://en.wikipedia.org/wiki/Perfect_fourth)

------
andrewla
> The acoustic structure of octaves is always the same: The frequency of a
> note in one octave is half the frequency of the same note in the octave
> above

This is not a great definition; our understanding of frequencies came well
after we were using the concept. The idea of a "string of half the length with
the same tension" is much more natural, and is the easiest mechanical analogy.
The discovery of this is very natural because you get sympathetic vibrations
-- you can feel the other string moving when you get consonance across
octaves. It shows up (along with fifths) in most other instruments -- blowing
twice as hard in a flute or halving the tube size, or compressing the
embouchure in brass instruments.

While I don't think it's intrinsic in the human brain, it is intrinsic in most
musical instruments, and it's kind of intrinsic in the way sound works, so it
would be very surprising if it didn't feature in the music made by a culture,
and thus work its way into the appreciation of music in general. The tests
described here are interesting but might just point to the fact that there is
less instrumental music (produced or listened to) in this culture than in
others.

------
seph-reed
I made a website that describes natural harmonic (just) tuning systems:

[http://just-tunings.info/learn](http://just-tunings.info/learn)

I do need to add a section on cultural consonance/dissonance but..

Octaves are _not_ cultural. Resonance is not just an aspect of music or even
animals, but literally everything in nature that makes sound. Dropping a rock
in water will create sound, and frequencies that resonate with each-other will
stick around longer than those that fight, teaching us that these sounds
_belong together_.

An octave is the simplest possible relationship between two frequencies, and
it can be heard in almost every natural sound imaginable. We learn they belong
together from almost every sound we hear.

As an aside, western tonality uses the twelfth root of 2 because if you just
start hammering randomly on those tones, they'll get along extremely well
regardless of whatever the biggest bassist vibration is. The big bassy
frequency being the one that every other frequency needs to get along with
(harder than it sounds). It's sort of a fudgy form of relativity that allows
things to vibe together mostly, but not perfectly.

------
byteface
I feel looking for musical scores in peoples brains is a great place to start
decoding. We clearly load data into a conscious signal somehow like CAN-bus
but it must also be stored maybe on actin filaments in the dendritic spines as
loops we load in? Also mentally we can change the music and add any number of
instruments over the top change the tune and deviate the course of the melody,
add vocal harmonies from crowds of people and violins etc. so where does that
part happen?, in the signal?. can it be 'heard'? . and is the music 'composer'
happening in the same part of the brain as the language generating part or is
it just similar capabilities in a different part of the brain?. Decoding must
be possible. I feel if they had like millions of brains all wired up to
computers that were using AI to find match patterns . i.e. audio patterns from
songs in brains data. they could brute force it? Is getting people to sing
stuff and making assumptions weak science?

------
raverbashing
I'm a bit skeptical of this

The concept of Octaves (as a lot of concepts in music) comes from physics.
Because one of the most basic instruments you can have is a string under
tension.

Pluck the string: note

Pluck the same string pinched in the middle: same note one octave higher

Not to mention Note + Note(octave higher) will have the harmonics overlapping,
so it will sound better since there won't be any beating.

~~~
bambax
Yeah, but the idea of half == same is very specific to music. In no other
domain do we do this.

~~~
smilespray
Half != same, and harmonics exist in plenty of other domains.

------
marci
It reminds me of how tuning can depend on the era. Sometimes even on the
composer. When you're used to hearing something in a particular way, the
slightest change can be jarring.

[https://www.youtube.com/watch?v=kyQaSFgnVI8](https://www.youtube.com/watch?v=kyQaSFgnVI8)

------
tathougies
Musical octaves are wired into physics. If a note is at frequency X Hz, then
the note one octave above it is 2X Hz. Of course due to the harmonics of the
string, a string vibrating at X is also vibrating at 2X, so when you play a
note at X Hz, then you are also hearing the note one octave above at the same
time.

So... it doesn't need to be learned... When you hear a middle A, you're also
hearing the A above for sure. And when you hear the A above by itself, you're
hearing one part of the A below.

Of course, understanding that what you're hearing is a called an octave is
almost certainly learned. But in my experience, any one who is not tone deaf
will naturally lower or raise their voice by an octave if you ask them to sing
a song 'lower'.

------
Asooka
I never understood octaves. Two sounds of different pitch that are supposed to
sound "the same" somehow? Obviously if you shift a melody by multiplying every
note by 2 will keep it sounding the same melodically, even though it's
immediately obvious it's higher pitched. Beyond that, I have never been able
to perceive the "sameness" between equivalent notes on different octaves. When
I was younger and played adventure games, sometimes there would be a puzzle
involving listening to a short melody and playing it back on some instrument.
Literally the only way I could solve those was by analysing the original
melody with a spectrometer, then analysing the instrument, and figuring what
sequence of keys to press that way.

~~~
tylerrobinson
I read this yesterday and it really stayed with me, enough to find this
comment again. Do two notes an octave apart not sound harmonious in a
particular identifiable way to you?

From another view, it may help to think about it like this: Tones have a
certain relationship with each other, and we split that into octaves in
Western music to keep track of them. Just like the number 9 precedes 10, and
19 precedes 20, 10 and 20 are "the same number" in base 10 since that's where
the pattern repeates. We could count in another number system, but the
underlying physical truth of the numbers would be the same.

------
hootbootscoot
mmmm I'm skeptical of a singular study in which a certain tribe of people are
asked to modulate a sound to an octave within their singing range disproving
octave equivalence being hardwired.

Wanna know why? Our aural circuits have frequency binning, much like an FFT,
and they "ring" at certain frequencies, and an octave is either 1/2 or 2x a
given frequency/"note". Closer examination of this system under stimulus is
what I would consider a gold standard in this field of research. The form of
research undertaken in this study suggests many things, and the researchers
have chosen a particular conclusion and it's not necessarily indicated by even
their own data.

[https://www.britannica.com/science/ear/Analysis-of-sound-
by-...](https://www.britannica.com/science/ear/Analysis-of-sound-by-the-
auditory-nervous-system)

Given the current propensity for thinking that frequency detection is pre-
cortex (lower level than speech decoding) and available rather early on in the
evolutionary chain, I'm going to be interested in physical studies, not social
science.

------
epx
Perhaps it depends on the environmental noise you are exposed. In nature, most
noise is percussion-like, non-rational harmonics, so octaves don't make much
sens. OTOH listening to electric motors and combustion engines since the day
you are born, makes you 'like' octaves, fifths and thirds, since these
rotational machines generate these intervals while doing noise.

~~~
Jarwain
This wouldn't explain the prevalence of the usage of these musical patterns
before electric motors and combustion engines were created

------
irrational
I hope that’s true because I still don’t have a clue what an octave is (or a
melody or harmony or any other music related word).

~~~
parenthesis
Notes separated by octaves are like higher and lower versions of the same
note.

If a deep-voiced person and a high-voiced person sing the same tune together
(without either straining), then they are singing one (or more) octaves apart.

Assuming they are singing in tune with each other, otherwise it will sound
more like Chick Corea demonstrates here:
[https://youtu.be/yfoxdFHG7Cw?t=371](https://youtu.be/yfoxdFHG7Cw?t=371)

~~~
taejo
> Notes separated by octaves are like higher and lower versions of the same
> note.

I don't know if this is an in-born ability or a cultural one, but I can say
that I (for one) don't have any perceptual sense of "sameness" in an octave.
To me, two keys with the same letter-name on a piano make two different notes,
just like any other interval (though I'm not saying that the different
intervals don't sound different). This may be a form of amusia, but I enjoy
music, sing to myself, recognize melodies, and find the dissonant Happy
Birthday in your link unpleasant (all of which contrasts strongly with the
forms of amusia I've read about); on the other hand a lot of the things that
people _say_ about music don't mean much to me, except that in some cases I
have a mathematical understanding which I can't really connect to a
perception.

------
dzdt
It was a surprise to me to learn that octaves have a physical. mathematical
basis. I discovered this as a teen reading about how to make music on a
computer, where the relationship of notes to frequency was explained. To my
ear moving up an octave had always sounded like an arbitrary increase in
pitch.

------
Grue3
Did they try to sing along to the original notes? Perfect pitch needs to be
practiced, but it should be immediately apparent when you sing out of tune if
you're even slightly musically inclined.

------
lukeschlather
I'm a little frustrated with the lack of discussion of frequencies in this
article, which seems like a key bit of background to understanding this work.
An "octave" is two sounds where one of them has exactly double the frequency
of the other. I think it makes sense that octaves aren't hardwired, however it
is fundamentally a mathematical property of frequencies.

I'm not sure how I feel about the thesis; can children tell if something is
twice the size of another or do you need the concept of "two?" I think like
other people I initially found this a little unlikely because octaves are
innate physical and mathematical properties, but there are tons of
physical/mathematical properties that require a lot of study to understand
intuitively.

------
jcims
Seems like most of the disagreement in the comments here are due to people
having different notions of the word octave. This should be no surprise as
there are numerous interpretations of the word according to Merriam-Webster:

1: an 8-day period of observances beginning with a festival day

2a: a stanza of eight lines : OTTAVA RIMA

b: the first eight lines of an Italian sonnet

3a: a musical interval embracing eight diatonic degrees

b: a tone or note at this interval

c: the harmonic combination of two tones an octave apart

d: the whole series of notes, tones, or digitals comprised within this
interval and forming the unit of the modern scale

e: an organ stop giving tones an octave above those corresponding to the keys

4: the interval between two frequencies (as in an electromagnetic spectrum)
having a ratio of 2 to 1

5: a group of eight

So maybe everyone's right.

------
hbarka
The Tsimane man could probably identify the distinction between octaves of
bird calls in his habitat. The experimenter would be in the opposite chair
hearing only a handful of notes.

------
fidla
As a music teacher and music therapist, I have observed this behavior for
three decades. It's especially true with people that have zero musical
background.

~~~
Asooka
If you don't mind me asking, what is a "music therapist"? You help people to
play music, or you help people using music?

------
kqr
I'm not too surprised by this. I've had awful relative pitch all my life, and
just recently started ear training. I've also for fun read a bit about how
absolute pitch develops in young children.[1]

Bit by bit, I'm realising how much of what's taken for granted by
practitioners of Western music is in fact learned.

As a concrete example: ever since I was a child, I've heard people speak of
major and minor triads as sounding happy or sad. That seems like something
that's just obvious to a lot of people. It's never been obvious to me, and it
lead me to think I was (at least partially) tone deaf; if I can't even hear
something that is (evidently) that obvious to so many people, how can I ever
get better at truly listening to music?

Now that I've started ear training, I'm beginning to mentally associate
particular sounds with these chord qualities[2] to the point of actually being
able to identify them better than a flipped coin would. (Which is a huge
milestone for me!)

But it's taken a lot of practise. And I still don't hear them as "happy" and
"sad". If I try to listen for "happy" and "sad" chords, I go back to
mischaracterising these chord qualities just as much as before. I've simply
never learned that association, for whatever reason.

\----

It goes on and on: I played a lot of piano (from sheet music) when I was
young, and practised the C major scale up and down and up and down, resulting
in the interval from the tonic to the major second being etched into my brain
very strongly. And I suspect this is what has made it surprisingly hard for me
to internally hear a half-step from the tonic. To my brain (before I started
ear training), the minimal possible step from the tonic was to the major
second. There just weren't any sounds my brain could produce in between.

Learned. With plenty of ear training, I'm now in addition learning to be able
to reproduce a minor second too.

Even more speculatively, I've noticed there are some specific half-step
intervals I hear as whole steps. These are from E to F, and from B to C. These
are half steps, but they are outliers in how often I attempt to classify them
as whole steps. I suspect this is because of said C major scale practise:
somewhere in the back of my mind, I might associate these tones (in the
absolute pitch sense) with steps of the C major scale and therefore think of
them as whole steps. I don't have absolute pitch in any useful sense, but it
wouldn't surprise me if my brain, somewhere in a back compartment somewhere,
has retained the sound of these tones and associated them with adjacent steps
in the scale I practised so much.

\----

Circling back to octaves: Yes, there are physical bases for considering
octaves as a special case of some sort, namely that if you strip out the base
resonance frequency of one tone on a string or wind instrument, what you're
left with are its overtones, which also makes up its octave's frequencies.

But the fact that this relationship is something that makes these tones sound
"the same" might very well be learned. The fact that this level of consonance
is even desirable might very well be learned. I can picture cultures in which
that level of consonance is considered uninteresting, hollow, and weak. Why
would one deliberately care to seek something like that?

\----

[1]: By listening a lot to music that extensively and unpredictably uses the
12 tones of Western music in A440 equal temperament tuning, children can learn
to recognise these specific 12 tones in that tuning – but it won't help with
any other frequencies!

[2]: I now hear major triads as a combination of hollow and triumphant, and
minor triads as fuller and more epic. Some parts of it make sense, others do
not.

~~~
marci
I wonder if the "humour" in switching the scale of well know songs will make
sense to you :
[https://www.youtube.com/watch?v=lYVzAFzmjW8](https://www.youtube.com/watch?v=lYVzAFzmjW8)

~~~
kqr
Well, there's a lot more to those performances than just switching the scale,
so I'm not sure it's a fair comparison. But no, without being told they were
switched from major to minor, I'm not sure I would have picked that out.

