35 ms·

Objects that have sharp edges generate higher frequency harmonics when agitated, because lower-size features resonate on higher frequencies (like shorter string

Objects that have sharp edges generate higher frequency harmonics when agitated, because lower-size features resonate on higher frequencies (like shorter strings ring on higher pitch). Objects that are round resonate on low frequencies only. The "kiki" sound has more high frequency content than the "bouba" sound, and it's no mystery why the brain associates one with the other.

mnbs 8mo ago
That's what I was thinking. But then I was wondering: if it was that obvoius, would there be such research about it?
- ACCount37 8mo ago
  You do need to research "obvious" things every once in a while. They have this annoying tendency of being proven wrong occasionally.
- rcxdude 8mo ago
  It's a hypothesis. How would you prove or disprove that it's because of that? (and I would say, a priori, it's not utterly obvious that the brain would relate spacial and temporal frequencies like this)
- PaulDavisThe1st 8mo ago
  Some of the research, including this paper, is trying to get at the question of whether a species' sensitivity to the bouba-kiki effect might be at the root of language or not. Since it seems accepted that chickens do not have language in any meaningful sense of that term, finding that they still show this effect decouples it from "the origins of language".
  - bondarchuk 8mo ago
    It shows that bouba-kiki is not sufficient, but it doesn't show that it is not necessary.
    - PaulDavisThe1st 8mo ago
      bouba-kiki has been previously shown not to exist for some set of other primates. given the general sense that they are closer to some form of language than baby chickens, its presence in the latter and absence in the former would suggested that it is not necessary. all this research could be deeply flawed, however.
      - bondarchuk 8mo ago
        Yes, see my other comment about primates https://news.ycombinator.com/item?id=47135674 https://news.ycombinator.com/item?id=47135674
IsTom 8mo ago
In nature there's few things laying around that resonate particularly well.
- maybewhenthesun 8mo ago
  Scratch a thin pointy branch across e rock -> sharp high noise. Thump a round club/log against a rock -> dull bump noise
  - IsTom 8mo ago
    Thump two round rocks together -> sharp noise Thump pointy branch against a tree -> dull noise And chickens aren't using tools.
    - blurbleblurble 8mo ago
      They're scratching for gizzard stones and food though, with their built-in beak, fwiw
    - sixsevenrot 8mo ago
      I challenge you to find two objects of a similar size and cut them into shapes that would produce a sharper sound for the rounder object. In your example it's obviously the round tree trunk that produces the dull sound.
- magneticnorth 8mo ago
  Hollow things are common, and of interest to many animals. If I thump a log and it makes a noise like it has a hollow space (low tones), then it may contain an animal nest or a beehive & honey, or it may be something I could use as a box or basket or shelter.
- ASalazarMX 8mo ago
  Maybe animal sounds count? Warning sounds tend to be loud, sharp, and high-pitched; and when ignored, they might end with more material sharp things in your skin. I can't recall any animal with a soft warning sound.
aaptel 8mo ago
I thought the same but they used chicks that just hatched with zero world experience.
- amelius 8mo ago
  World experience can be encoded through evolution. E.g. a spider does not learn if/how to weave a web from its parents.
deleted 8mo ago
[deleted]
GuB-42 8mo ago
That's one theory. Another one I can think of is that sharp edges are scary, and most distress calls are high pitched. Also, the thing about high frequencies and sharp edges lead to a contradiction: babies are more round than adults and produce higher pitched sounds, this is almost universal across all species. There are other tentative explanations, such as how the vocal tract acts when producing these sounds, with "bouba" sounds being the result of smoother movement more reminiscent of a round shape. "kiki" is not just higher pitched, it is also "shaped" differently if you look at the sound envelope, with, as expected, sharper transitions. So to me, the mystery is still there. Is is the kind of thing that sounds obvious, in the same way that kiki sounds obviously sharper than bouba, but is not.
- scrumper 8mo ago
  > Also, the thing about high frequencies and sharp edges lead to a contradiction: babies are more round than adults and produce higher pitched sounds, this is almost universal across all species. It's more in terms of harmonic content than the pitch fundamental. There are more harmonics from a thing with sharp transitions than there are in a thing with rounded transitions regardless of the fundamental pitch. Compare harmonic content of a pure sine wave (it's just the fundamental) with that of a square wave, which has an infinite series of higher harmonics. Babies are also smaller, which means higher fundamental pitch. > "kiki" is not just higher pitched, it is also "shaped" differently if you look at the sound envelope, with, as expected, sharper transitions. Exactly! EDIT I think this is interesting: it also applies to images as well, not just sound. You can "low pass filter" a photograph and it'll reduce some of the detail, smoothing out transitions (typically used for noise reduction). Detail is high frequency information (or high frequency noise depending on whether you want it or not.)
  - saalweachter 8mo ago
    So you know the "bock bock" sound? Hens make it occasionally when laying eggs, but it's also the rooster alarm sound. The "cock-a-doodle-doo"/crowing sound is more the all-clear/I'm-a-rooster-here-I-am/flock-assemble cry. When there's a threat, the rooster switches to a loud, BAWK BAWK BAWK alarm.
PaulDavisThe1st 8mo ago
So then the mystery would be why other primates do not appear to show the bouba-kiki effect ...
littlestymaar 8mo ago
> The "kiki" sound has more high frequency content than the "bouba" sound And where did you get that from? In non-tonal languages the pitch conveys almost no information and people speak at very different ones (and for instance a male saying "kiki" will say it at lower frequencies than a woman saying "bouba" most of the time) so I find your affirmation very dubious. > and it's no mystery why the brain associates one with the other. Specialists of the field find that mysterious but some smartass on HN disagrees.
- IAmBroom 8mo ago
  > > The "kiki" sound has more high frequency content than the "bouba" sound > And where did you get that from? In non-tonal languages the pitch conveys almost no information and people speak at very different ones (and for instance a male saying "kiki" will say it at lower frequencies than a woman saying "bouba" most of the time) so I find your affirmation very dubious. You misunderstand the post. It has nothing to do with the voice of the speaker. Long drawn-out sounds have lower frequency components than short-lasting sounds. A pin drop is REALLY high-pitched; a moan has at least some low-pitch components (but may still be high-pitched, too - more often called a "keening" than a moan). It's not about intonation; it's a mathematical consequence of the relationship between frequency and time-domain incidents, typically measured with Fourier transforms.
  - littlestymaar 8mo ago
    Sigh.

mnbs 8mo ago

That's what I was thinking. But then I was wondering: if it was that obvoius, would there be such research about it?

ACCount37 8mo ago
You do need to research "obvious" things every once in a while. They have this annoying tendency of being proven wrong occasionally.
rcxdude 8mo ago
It's a hypothesis. How would you prove or disprove that it's because of that? (and I would say, a priori, it's not utterly obvious that the brain would relate spacial and temporal frequencies like this)
PaulDavisThe1st 8mo ago
Some of the research, including this paper, is trying to get at the question of whether a species' sensitivity to the bouba-kiki effect might be at the root of language or not. Since it seems accepted that chickens do not have language in any meaningful sense of that term, finding that they still show this effect decouples it from "the origins of language".
- bondarchuk 8mo ago
  It shows that bouba-kiki is not sufficient, but it doesn't show that it is not necessary.
  - PaulDavisThe1st 8mo ago
    bouba-kiki has been previously shown not to exist for some set of other primates. given the general sense that they are closer to some form of language than baby chickens, its presence in the latter and absence in the former would suggested that it is not necessary. all this research could be deeply flawed, however.
    - bondarchuk 8mo ago
      Yes, see my other comment about primates https://news.ycombinator.com/item?id=47135674 https://news.ycombinator.com/item?id=47135674

IsTom 8mo ago

In nature there's few things laying around that resonate particularly well.

maybewhenthesun 8mo ago
Scratch a thin pointy branch across e rock -> sharp high noise. Thump a round club/log against a rock -> dull bump noise
- IsTom 8mo ago
  Thump two round rocks together -> sharp noise Thump pointy branch against a tree -> dull noise And chickens aren't using tools.
  - blurbleblurble 8mo ago
    They're scratching for gizzard stones and food though, with their built-in beak, fwiw
  - sixsevenrot 8mo ago
    I challenge you to find two objects of a similar size and cut them into shapes that would produce a sharper sound for the rounder object. In your example it's obviously the round tree trunk that produces the dull sound.
magneticnorth 8mo ago
Hollow things are common, and of interest to many animals. If I thump a log and it makes a noise like it has a hollow space (low tones), then it may contain an animal nest or a beehive & honey, or it may be something I could use as a box or basket or shelter.
ASalazarMX 8mo ago
Maybe animal sounds count? Warning sounds tend to be loud, sharp, and high-pitched; and when ignored, they might end with more material sharp things in your skin. I can't recall any animal with a soft warning sound.

aaptel 8mo ago

I thought the same but they used chicks that just hatched with zero world experience.

amelius 8mo ago
World experience can be encoded through evolution. E.g. a spider does not learn if/how to weave a web from its parents.

deleted 8mo ago

[deleted]

GuB-42 8mo ago

That's one theory. Another one I can think of is that sharp edges are scary, and most distress calls are high pitched. Also, the thing about high frequencies and sharp edges lead to a contradiction: babies are more round than adults and produce higher pitched sounds, this is almost universal across all species. There are other tentative explanations, such as how the vocal tract acts when producing these sounds, with "bouba" sounds being the result of smoother movement more reminiscent of a round shape. "kiki" is not just higher pitched, it is also "shaped" differently if you look at the sound envelope, with, as expected, sharper transitions. So to me, the mystery is still there. Is is the kind of thing that sounds obvious, in the same way that kiki sounds obviously sharper than bouba, but is not.

scrumper 8mo ago
> Also, the thing about high frequencies and sharp edges lead to a contradiction: babies are more round than adults and produce higher pitched sounds, this is almost universal across all species. It's more in terms of harmonic content than the pitch fundamental. There are more harmonics from a thing with sharp transitions than there are in a thing with rounded transitions regardless of the fundamental pitch. Compare harmonic content of a pure sine wave (it's just the fundamental) with that of a square wave, which has an infinite series of higher harmonics. Babies are also smaller, which means higher fundamental pitch. > "kiki" is not just higher pitched, it is also "shaped" differently if you look at the sound envelope, with, as expected, sharper transitions. Exactly! EDIT I think this is interesting: it also applies to images as well, not just sound. You can "low pass filter" a photograph and it'll reduce some of the detail, smoothing out transitions (typically used for noise reduction). Detail is high frequency information (or high frequency noise depending on whether you want it or not.)
- saalweachter 8mo ago
  So you know the "bock bock" sound? Hens make it occasionally when laying eggs, but it's also the rooster alarm sound. The "cock-a-doodle-doo"/crowing sound is more the all-clear/I'm-a-rooster-here-I-am/flock-assemble cry. When there's a threat, the rooster switches to a loud, BAWK BAWK BAWK alarm.

PaulDavisThe1st 8mo ago

So then the mystery would be why other primates do not appear to show the bouba-kiki effect ...

littlestymaar 8mo ago

> The "kiki" sound has more high frequency content than the "bouba" sound And where did you get that from? In non-tonal languages the pitch conveys almost no information and people speak at very different ones (and for instance a male saying "kiki" will say it at lower frequencies than a woman saying "bouba" most of the time) so I find your affirmation very dubious. > and it's no mystery why the brain associates one with the other. Specialists of the field find that mysterious but some smartass on HN disagrees.

IAmBroom 8mo ago
> > The "kiki" sound has more high frequency content than the "bouba" sound > And where did you get that from? In non-tonal languages the pitch conveys almost no information and people speak at very different ones (and for instance a male saying "kiki" will say it at lower frequencies than a woman saying "bouba" most of the time) so I find your affirmation very dubious. You misunderstand the post. It has nothing to do with the voice of the speaker. Long drawn-out sounds have lower frequency components than short-lasting sounds. A pin drop is REALLY high-pitched; a moan has at least some low-pitch components (but may still be high-pitched, too - more often called a "keening" than a moan). It's not about intonation; it's a mathematical consequence of the relationship between frequency and time-domain incidents, typically measured with Fourier transforms.
- littlestymaar 8mo ago
  Sigh.