This is just one micro-instance of a much larger thing. Brain encodes structural similarity across modalities. Corollary: language is far from arbitrary labels for things.
I think it’s natural to think of this in terms of frequencies so the kiki shape has a higher visual frequency. As does the word have a higher audio frequencies within in than bouba so that is naturally associated with the lower frequency undulating line of that shape.
I'm not entirely sold by this discovery. For example when you learn to train dogs, you learn about the 3 voices. Encouraging voice, atta boy, negative voice, more stern, and the big "NO!".
To some degree these words type sounding language are doing the same thing. Some sounds will irk, some will soothe, and it would affect this 'evidence' found.
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.
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.
> 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.
> > 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.
For each chick they do 24 trials divided into 4 blocks with retraining on the ambiguous shape and actual rewards after each block. During the actual tests they didn't give rewards. In figure 1 they show the data bucketed by trial index. It's a bit surprising it doesn't show any apparent effect vs trial number, e.g. the first trial after retraining being slightly different.
I have to admit I'm super skeptical there's not some stupid mistake here. Definitely thought provoking. But I wish they'd kept iteratively removing elements until the correlation stopped happening, so they could nail down causation more precisely.
I do agree my skepticism level rises extremely high in any experimental psychology experiment. There’s just so many ways to bias results, in addition to “do enough experiments and one of them will get a statistically unlikely result” problem.
This group does a lot like this https://www.dpg.unipd.it/en/compcog/publications … so that’s tempting to think they keep trying things until something odd happens (kind of like physicists who look for 5th forces… eventually they find something odd but often it’s just an experimental issue they need to understand further).
Very likely this experiment suffered from a lack of thorough double blind control. Researcher bias may have generated subtle subconscious queues to the chicks on which shape to pick unrelated to the sounds.
I see several people say primates don't show the effect, however all tests on primates were done with a "language-competent bonobo" and "touchscreen trained chimpanzees (N=6) and gorillas (N=2)" that are first trained to do various language/picture association tasks and then tested like how you'd test humans. It would be interesting to test primates using the same methodology they used here on chickens. The previous language/computer training in the monkeys might have interfered with a more low-level/intuitive bouba-kiki effect.
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[ 2.5 ms ] story [ 56.8 ms ] threadBut I guess it's about why so we associate those with spiky shapes, though surely it's because they represent sharp immediate changes in frequency?
I'd be interested on results of shapes imagined when you take the source as musical or other non speech sounds.
To some degree these words type sounding language are doing the same thing. Some sounds will irk, some will soothe, and it would affect this 'evidence' found.
It must take some strange things to survive co-evolution with humans for several thousands years
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.
Formulating theories is all nice and dandy, but it ain't science.
Does the original paper (I couldn't find it in the article) explore this a bit more ?
It's actually nice if the effect can be studied on chickens, they are definitely less expensive and more plentiful than human babies.
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.
> 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.
I have to admit I'm super skeptical there's not some stupid mistake here. Definitely thought provoking. But I wish they'd kept iteratively removing elements until the correlation stopped happening, so they could nail down causation more precisely.
This group does a lot like this https://www.dpg.unipd.it/en/compcog/publications … so that’s tempting to think they keep trying things until something odd happens (kind of like physicists who look for 5th forces… eventually they find something odd but often it’s just an experimental issue they need to understand further).
References here https://evolang.org/jcole2022/proceedings/papers/JCoLE2022_p...