Evidence of the bouba-kiki effect in naïve baby chicks | Hacker News Reader

Evidence of the bouba-kiki effect in naïve baby chicks

science.org

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

You do need to research "obvious" things every once in a while. They have this annoying tendency of being proven wrong occasionally.

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)

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".

It shows that bouba-kiki is not sufficient, but it doesn't show that it is not necessary.

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.

Yes, see my other comment about primates https://news.ycombinator.com/item?id=47135674

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

Scratch a thin pointy branch across e rock -> sharp high noise.

Thump a round club/log against a rock -> dull bump noise

Thump two round rocks together -> sharp noise

Thump pointy branch against a tree -> dull noise

And chickens aren't using tools.

They're scratching for gizzard stones and food though, with their built-in beak, fwiw

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.

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.

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.

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

World experience can be encoded through evolution.

E.g. a spider does not learn if/how to weave a web from its parents.

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.

> 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.)

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.

I agree! Wouldn't it be scientific to test this with other sounds of round and spiky objects?

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.

> Formulating theories is all nice and dandy, but it ain't science.

Formulating theories ain't the whole of science, but it's a big part of it.

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

> 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.

Sigh.

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).

Preprint: https://www.biorxiv.org/content/10.1101/2024.05.17.594640v1....

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.

>language is far from arbitrary labels for things

I think this is a misunderstanding of the arbitrariness of the sign. Arbitrary doesn't mean "random" or "uniformly sampled." The fact there are systematic tendencies among languages in how things are called doesn't negate the arbitrariness of the sign, they could have been called other things. We can also decide to refer to things by another name and we can use any arbitrary name we like! There is no limits on what names we can use (besides silly physiological constraints like having a word with 50 000 consonants). But, of course, there's much more to language than just labels!

For me, the interesting thing in this paper vis-à-vis language is that it shows how much innate structure in cognition must shape our language.

Arbitrariness of the sign is a principle that requires so many epicycles to present as "true" that it's more of a warning against overgeneralization than an insight with any significant predictive power in its own right.

Let's call the arbitrariness of the sign, blinga. Why do you think blinga requires "epicycles"? Blinga makes pretty modest claims: there is no requirement that the form of a sign matches that which it signifies in any way.

https://en.wikipedia.org/wiki/True_name

No, language is still pretty close to arbitrary labels. The handful of tenuous common threads like the bouba-kiki effect don't change the overall picture that much. The simple fact that language varies as much as it does is sufficient to prove that it's only loosely bound to anything universal.

Maybe it goes to show that animals just have some of the same brain structures associated with language that we do. Parrots are capable of rather sophisticated language use, and the informal word-button experiments suggest that non-avian animals like cats and dogs display some linguistic ability. So the bouba-kiki effect in animals shouldn't be terribly surprising. Certain mammals and birds perhaps may best be thought of as prelinguistic.

> the informal word-button experiments suggest that non-avian animals like cats and dogs

I always wanted to see long form content on this. Like I'm sure the cherrypicked clips make it look more impressive than reality but I've owned enough pets to believe they can understand more than just individual words / tone.

Here is a video that I actually just watched recently on that exact thing.

https://youtu.be/jfLAaGtNc7U

I get:

The uploader has not made this video available in your country

:( didn’t know that this was a thing

Neither did I, feel free to email me or message me on discord and I can try to download the video and send it to you.

It's your lucky day

https://www.youtube.com/watch?v=iXJfK1wR_w0

Buddhism, Out-of-Africa, Talking Dogs | Robert Sapolsky Father-Offspring Interviews #96

Research implies that - no, pets don't have complex understanding of word combinations, beyond the usual commands. But, in terms of recognizing words individually - some of the gifted ones show abilities on par with 18-month-old humans.

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.

I think the researchers agree with your premise. The “evidence” is not that chicks have more language understanding than previously understood, but rather that the source of the universality of bouba/kiki is due to something more primitive than built in human language hardware.

Is this not reducible to whether a speech sound contains fricatives and stops or not? They produce spiky sounds

But 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.

>But I guess it's about why so we associate those with spiky shapes

I think the why just got a lot tricker than we imagined. Because we failed to replicate this experiment on other primates, we couldn't avoid a semantic suspicion about those associations. Now we probably have to set semantics aside or let it get a lot weirder, because we can replicate across ~300My.

>surely it's because they represent sharp immediate changes in frequency?

Maybe, and I think "multi-sensory signal processing" is the best framing, but the representation could also carry harder to think about things like "harm".

It's also super cool because the bouba-kiki effect framing was chosen due to methodological convenience for linguists and cultural anthropologists and their experimental bounds, not neuroscientists or signal processing folks. We could potentially find other experiments quickly, since chicks are a model organism and the mechanism is clear.

Things could move fast here.

> But 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?

Sure, but it's a very abstract connection between objects being sharp in vision and frequencies changing sharply in hearing. There's no guarantee any given organism would make the connection.

I don't think it's abstract at all. Rub something sharp (anything from a stick to a phonograph needle) on an object and you'll directly transcribe its spatial frequency spectrum into an audio frequency spectrum.

Do you think it's obvious that a chick would understand that connection?

It's not about "understanding" that you or me do when we read a wikipedia article. It's about the mechanisms in the brain that encode things.

"Spatial frequency spectrum" typically refers to visual elements of an object, and has nothing particularly to do with its structure. Entirely smooth surfaces banded in different colors have a "spatial frequency". Extremely irregularly surfaces have no effective spatial frequency. Objects on the same scale as, say, a human head, would have to be "rubbed" at ridiculous high rates (and repeatedly) to even get into a "frequency" range that might include pressure variations that would be considered as a "wave".

I think you're imagining an entirely too limited set of objects.

In the book „the design of everyday things“ it is mentioned that „natural mappings“ exist. Moving the knob of a vertical slider to the upper end universally means „brighter“ or „louder“, not „less bright“ or „more silent“.

maybe the chicks and norman get it, but i'm currently renting an apartment in france that has a bunch of these light switches installed all upside down, with "-" at the top:

https://www.legrand.com.gh/en/catalog/products/arteor-push-b...

> Moving the knob of a vertical slider to the upper end universally means „brighter“ or „louder“, not „less bright“ or „more silent“.

Except for the organ drawbars?

But then you are "pulling out the stops"! That sounds louder, doesn't it.

Which way would a vertical weight slider go?

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.

https://news.ycombinator.com/item?id=44280619 it's a good analogy.

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.

References here https://evolang.org/jcole2022/proceedings/papers/JCoLE2022_p...

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'm very intrigued by this, but I'll be much more interested when this is replicated on non-domesticated animals...!

It must take some strange things to survive co-evolution with humans for several thousands years

I don't really see how it challenges any theory of language evolution. The bouba kiki effect is hardly necessary nor important for having language.

This is downvoted, perhaps as a 'lazy dismissal'? But I read the SciAm article and I don't think it actually explained this point.

The finding seems to be that the bouba-kiki effect is not specific to humans and does not depend on experience. And the previously-existing theory is presented like so:

> scientists have considered [the bouba-kiki effect] a clue to the origin of language, theorizing that maybe our ancestors built their first words upon these instinctive associations between sound and meaning.

The finding is supposed to undermine, or at least challenge, the theory. But why? Is the point just that, if other species also have the bouba-kiki effect but do not have language, the bouba-kiki effect probably doesn't play as important a role as we thought? That seems to be the implication (though the innate/learned distinction also seems to be relevant, and I'm not sure why that is) -- but surely the bouba-kiki effect was never believed to be anything like a sufficient condition for the development of language, was it?

Yeah I'm not sure why it's being downvoted, I don't dismiss the study at all (I'm the one who originally posted it!). I just think the scientific reporting on it is very odd. It's an interesting study in terms of what it has to say about innate vs learnt associations.

>scientists have considered [the bouba-kiki effect] a clue to the origin of language, theorizing that maybe our ancestors built their first words upon these instinctive associations between sound and meaning.

I suppose just working in linguistics, I find this such a fringe and unserious theory. The hard part of language isn't associating sounds with objects (dogs can do that), it's putting those words together to make novel meanings.

The word "challenge" in the article title is clickbait. I guess the assumption challenged is that this measurable effect is for humans only because we are so special? Good as a headline for a non-science audience that mostly doesn't believe in evolution. It's pretty obvious that our auditory and visual systems are older than humanity as a species. I'd be surprised if the results were anything but confirming. Chickens are not going to learn English. Other species use sound to communicate and that this effect is measurable is pretty cool.

But no serious linguist thinks that kiki-bouba is that important to language. It's a theory that mistakenly thinks that hard problem in language is coming up with words for objects instead of the actually hard problem of combining words in a systematic way.

> But no serious linguist thinks that kiki-bouba is that important to language.

Do you have a source on that? Because I would expect anyone studying sound symbolism to find the bouba-kiki effect extremely important which is probably why it's such a widely cited study, also inside linguistics.

It's hard to find a source for that kind of negative statement.

Kiki-bouba is important for sound-symbolism definitely! But sound-symbolism is marginal when it comes to language. Iconicity and similar things are very interesting phenomena but they're not the difficult part of language at all and they're not necessary parts of language.

I obviously don't know your background but out of the linguists that I know and have met while doing my degrees in linguistics, I don't know of anyone who would say that the kiki-bouba effect is not important — anything, in fact, that challenges the notion that sound-meaning relations are completely arbitrary is interesting because it might give us clues about the origins of language, not to mention that it lends support to other, related hypotheses about sound-symbolism.

I'm not sure what you mean by "not necessary parts of language", but I would love to hear what you think the necessary parts of language are. Not to mention, what is "the difficult part of language" then?

The Bouba kiki effect doesn't challenge the arbitrariness of the sign because arbitrary doesn't mean uniformly distributed. The effect shows that there's a preference between the two but it doesn't contradict the fact that either could be a perfectly fine label.

The difficult part of language is the fact we can build entirely novel meanings out of a relatively small finite set of words. Bouba kiki has no bearing on the way words are composed.

> The difficult part of language is the fact we can build entirely novel meanings out of a relatively small finite set of words.

So are you saying that we've got e.g. neurolinguistics, psycholinguistics, language acquisition and typology down? Or do you simply mean "interesting to you" when you say "difficult"? Because in my experience, pretty much every subject in linguistics (and most other sciences) is easy if you don't understand it and surprisingly difficult once you start to get a grasp of it.

> Bouba kiki has no bearing on the way words are composed.

It literally shows a preference best described by sound-symbolism so it most certainly has a bearing on how words are composed. Just because the relation between sound and meaning _can_ be arbitrary, showing that in some cases it's not entirely so is extremely valuable for evolutionary linguistics.

The mainline opposing view to evolution seems to be that one guy made all living beings over the course of a week. Common brain structures should be even less surprising in that scenario. That'd just be God taking what works and reusing it, either refining it for a more intelligent species or removing parts that are not needed but leaving some of the supporting infrastructure around

After all, lazy engineers are made in God's image /s

> a non-science audience that mostly doesn't believe in evolution

This isn't true anywhere in the world except Turkey. Even the second least "evolution believing" country in the world, USA, has 54% of the general public accepting evolution and only 31% believing in creationism, as of 2009.

I fonud the following Wikipedia section somewhat useful for understanding the context here: https://en.wikipedia.org/wiki/Bouba/kiki_effect#Implications...

Annoyingly, very few of the citations are accessible. But the gist as I understand it is that this challenges various proposed explanations for the Bouba-Kiki effect, for example that it relates to human physiology or has a human-specific neurological basis.

So, the next version of Jurassic Park will have a talking velociraptor ?

(More honest question: is there enough info in the skeletons / fossils that we have to exclude the possiblity that birds ancestors could modulate sound enough to have "something" like a language, which would have been "lost" after extinction events ?)

Birds have a language, most mammals do too. Those languages are usually much simpler than ours though.

They communicate, but communication is not the same thing as language.

For anyone else whom the above awnsers absolutely nothing without googling what defines the boundary - A more verbose version of the above comment is that they communicate only simple, situational signals (like warning cries or information for action) and not using a symbolic, rule-governed system capable of abstraction, past and future tense, and infinite combination.

Of course, with all generalizations, this is sort of a lie, but no - whales, chimps and cephapods don't meet the official bar.

Or they communicate in languages we cannot understand.

Even among human languages the sounds of some languages sound all the same to humans who are not native speakers of that language.

Chinese for example has a million words that all sound like "shi" and other tonal languages like Vietnamese are also indistinguishable to English natives etc. Japanese people treat R/L the same.

Elephants and dolphins have been known to assign unique names for each other.

Octopuses and other cephalopods communicate by changing the color of their skin, EVEN WITH SOME OTHER FISH! BBC's Blue Planet has an episode where an octopus and a grouper fish coordinate via color to trap prey.

Ants and other insects communicate via pheromones and "smell".

Are you seriously going to stick to a human-chauvinistic stance that only we have a "language"?

I'm a linguist and yes I'll stick to that "human-chauvinistic stance until an animal can tell me otherwise.

I mean there are space physicists who don't understand dark matter, etc.

I think this is a "qualia" issue: Like for example biologists can find out what kind of light frequencies the eyes of a mantis shrimp can receive, but we'll never know what it FEELS like to be able to see a zillion times more colors.

You can see this happen with human languages too: Ever walk around in a different country? your brain doesn't even register the sounds other people are making.

It turns out that the fact that mantis shrimp have 12 different color receptors in their eyes means they can see... 12 colors. They can't combine the input from the different color receptors into a spectrum like we and other vertebrates can. Their eyes even perceive different things in different regions of the compound eye. It's a surprisingly limited visual system for all its supposed extra capabilities compared to ours, which to your point makes "seeing like a mantis shrimp" even more inscrutable from our POV.

Nnnooooo they nerfed my hero!!

"For over two decades, Professor Toshitaka Suzuki dedicated his life to studying the Japanese tit — a small songbird native to Japan’s forests. Through years of careful observation and experiments, he discovered something incredible: these birds use grammar-like rules and combine sounds to form meaning, much like how humans use language."

https://www.youtube.com/watch?v=jmys2abx4co

I'm familiar with this case. The "language" of the birds is so profoundly primitive (it's limited to 2 word combos where the meaning is just the meaning of both words). Here's a good blogpost about it.

https://facultyoflanguage.blogspot.com/2016/03/a-triple-of-r...

If we're going to be able to have a meaningful discussion on this, first you will need to provide for me the definition of language under which you're operating.

This takes more than just being a "linguist"; you need to be a biolinguist/xenolinguist :)

This is already sort of in Jurassic Park 3, which features a 3D-printed velociraptor larynx that can be blown into to reproduce vocalizations remniscent of the velociraptors in the movie. At the end of the movie Alan Grant blows in it, confusing a pack of velociraptors.

There's a specific call that the movie has established as velociraptors in distress calling for help/backup from the pack, and Alan attempted to reproduce it when cornered at the beach to basically bluff/intimidate the pack into avoiding a fight. It coincided with the arrival of a helicopter, and the combined effect made the raptors run away.

Not explicitly a language as such, but specific calls with understandable, relatively complex meaning to the dinosaurs, that can be (sorta) understood and leveraged by humans.

https://archive.ph/QX0Oo

What's the N value of this study

I don’t know, but it really should be in units of N dozen.

From the preprint linked above:

> We tested a total of 42 subjects, 17 of which were females.

The published one repeated the experiment w/ day old chicks and IIRC the same number w/ the same results, so it's got a little more N than the preprint.

Are all brains somehow able to visualize spiky waveforms and smooth ones?

I wonder if this is a result of a Fourier transform type operation that turns the serial time domain into something that can be processed in parallel?

As someone with a passing familiarity with both baby chicks and experimental setups, I have strong doubts about this research.

which came first: the chicken or the egg? language.

Fun joke! Eggs are really old evolutionarily. Over 600 million years old if you count preamniotes.

You could still say that's recent on the evolutionary time span, given that life on Earth is ~3.5-3.7 billion years old. (Which is within the same order of magnitude as the age of the universe - which is itself wild to ponder.)

Chickens are a human invention.

It's fun to think about theropod language centers. Raptor kiki bouba.

baba is keke

baba is you

All the universal translators in fiction make more sense now lol.

Believe it or not: This is pure and unadulterated advancement of civilization.

Please elaborate.

This is irony. The study is stupid, society has reached a stupid stage of development. Kiki and bouba explain nothing and serve nothing. Culture is in shambles.

Okay Gemini

If you don't recognize a quote, it's obviously AI? Might want to rethink your logic, or outsource it to AI. Might help you

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