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Comment by DrProfresher | Hacker News Reader

As a human I agree with dogs that 'Bouba' is round and 'Kiki' is spiky.

In all seriousness, and I am surprised the article does not mention this, as dumb as it sounds Kiki has "sharp" sounds when pronouncing it and "Bouba" has a softer feel to it when pronouncing it.

As the article says it does not matter what language you speak, a word that quickly changes the sound back and forth to the same thing sounds sharp because that is how sharp things look and feel. The serration on a knife has the same angle on either side leading to a point. This is what makes sense to me as to why we correspond Kiki to something sharp.

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> In all seriousness, and I am surprised the article does not mention this, as dumb as it sounds Kiki has "sharp" sounds when pronouncing it and "Bouba" has a softer feel to it when pronouncing it.

This is just the same thing though?

It's not actually trivially obvious that different minds would agree on how "sharp" and "soft" apply to sounds and to shapes.

It isn't trivially obvious, no, but the "k" sound is a fricative (EDIT: oops, nope, plosive - see response to this comment), i.e. the tongue rapidly moves close to the palate and then away, creating turbulence, and sounds with a sharp peak and amplitude. I.e. the waveform of a "k" or "kiki" sound looks more spiky. The opposite is the case for the "bouba" sound.

It is a bit mysterious why animals would all map e.g. sharp auditory waveforms to sharper / spiky lines (kiki figure), and then smoother sounds to smoother lineforms (bouba figure), but, reasonably, these senses evolved together and used far more shared underlying processing machinery than they do presently. After all, both light and sound reach us in waves and both carry energy.

Some primitive mush-blob perhaps just started processing all incoming energy waves together, differentiating e.g. smoother vs. more staccatto waves before making the distinction between e.g. sound vs. light. Or I dunno, but IMO it makes more sense when you consider evolution, and don't just look at processing now in isolation from the likely development of these senses.

The 'b' sound is a plosive too, by the way. It's voiced, vs the voiceless 'k'.

But the place of articulation kinda flips, from rear consonant/front vowel (kiki), to front consonant/rear vowel (bouba).

If you flipped the voicing, it'd be 'gigi' vs 'poupa', which to my ears at least, is a lot less clear cut.

> The 'b' sound is a plosive too, by the way. It's voiced, vs the voiceless 'k'.

Yeah this I know, by "bouba" being opposite I meant the waveform.

Really the phonetic terms here are not actually relevant and have betrayed me. It's more that the 'k' sound is "more [ex]plosive" in that it seems to build up more pressure and turbulence (probably as you say, because the consonant is in the rear, so pressure builds and bounces around in the mouth more, whereas the "b" just mostly blasts out the front more quickly). And the "k" surely has a more peaky / spikey waveform in the audible range.

If you, or anyone else reading, is interested in playing around with this stuff, there's an open source program called Praat[0]. I assume it still is the go-to in linguistics for making spectrograms, it was back when I was studying it, at least.

There's probably nicer programs that can do the same thing, aimed at people like musicians, but they won't have the phonetics-specific guides and help online.

There's also a large archive of speech recordings from a wide range of languages hosted by UCLA[1], which you can download and play around with. There might be newer archives now, but I remember this one, because Peter Ladefoged wrote the proverbial book on introductory phonetics.

Linguistics generally aligns quite pro-copyleft, so there will be a lot of freely available stuff online.

[0]: https://praat.org/ [1]: https://archive.phonetics.ucla.edu/

k is a plosive, not fricative: there's a discontinuity in the flow of air, not a friction-sounding continuous airflow. that fits your point though, regardless.

Oops, you are right! Thank you for correcting. I checked before posting that some "k" sounds are indeed fricatives, but they definitely aren't in "kiki".

Well /b/ is also a plosive. :) Phonetics is out to sabotage your meaning.

If I stick to the more familiar territory of bad speech synthesis on 8-bit computers using envelopes, /k/ probably starts with a burst of white noise.

> Well /b/ is also a plosive. :) Phonetics is out to sabotage your meaning.

Lol, true.

Sure it is. Fourier transform - Bouba and Kiki are far from the same there. And as someone else mentioned, time domain content - attack and decay. There are physical differences in the sounds which are pretty fundamental and can be definitionally linked to sharpness and softness across domains, especially as sharp objects are defined in nearly exactly the same way (except spatially).

It would be more interesting if we had two sounds which didn’t have such apparent objective differences giving rise to specific and universal subjective differences, or if something that was not so cross domain elicited a different response, e.g. linking volume with sharpness as opposed to something like size.

Depending how you pronounce bouba and kiki, they are actually very similar sounds. 2 syllables made with sudden stops of air - one by the lips, and the other by the throat. The attack and decay are very similar too. There's no obvious reason why we call one "sharp" and the other "soft".

So why is a spiky Fourier transform related to a spiky object? Are dogs visualising the frequency domain signal in their heads and seeing that it is spiky?

Not my claim, what I am saying is that as long as there is a physical connection between these domains we can’t be surprised about universal representations. In a spatial Fourier transform, spiky things have high frequency information. In a time Fourier transform, spiky sounds have high frequency information. In space, spiky things have sharp edges (attack). In time, sharp sounds have faster attack. The presence of a physical analogue here means that all these experiments are testing is whether brains identify this existing connection.

It would be more surprising if the connection was indicative of genuine universality of brains and their representations, rather than ability to identify a cross-domain mathematical/physics-cal connection.

When I want to avoid startling my cat I make sure that the sound of my presence is gradual and not sudden. The syllables of a bouba word all introduce themselves smoothly and not suddenly.

I’ll rush to posit something for others to poke holes in: the definition of a Kiki word is a word where the syllables have a sudden “attack” then decay. And that’s a function of sound, not language.

How about high frequency sounds? Kiki must be higher frequency on a spectrograph. Spikes make high frequency sounds when they hit against things. Soft round objects make low frequency noises. Sort of. (There's holes in this theory, because fur is soft but makes high frequency sounds when brushed.)

>It's not actually trivially obvious that different minds would agree on how "sharp" and "soft" apply to sounds and to shapes.

Same genetics produce the same outcome (mostly).

Interestingly, even the sound of the word ‘round’ feels gentle, while the word ‘spiky’ has high-frequency peaks (at p and k)! I wonder if dogs (or for that matter, humans) can accurately zero-shot classify words that represent round vs spiky for different languages.

It appears to me that onomatopoeia, at varying degrees, played a role in the spontaneous convergence of verbal communication, and thus the development of a language.

When I studied psychology 20 years ago we had a class which covered this, and at least then there were studies indeed showing these associations are exactly due to these phonetic identifiers.

Across multiple non-European languages?

You could say it has a sort of woody quality about it.

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