I too would associate "Bouba" with the rounded and "Kiki" with the sharper figure, but to me this is just a relatively universal sense of continuity vs discontinuities:

the local curvature is continuous for "Bouba", every point on the curve has a single tangent, which evolves continuously as you walk along this presented curve.

For Kiki: the local curvature is discontinuous: at the inward or outward points, there are 2 tangents, so the tangent abruptly switches value when passing through this point when walking along the curve.

similarly the "B"s in "Bouba" are voiced plosives, while the "K"s in "Kiki" are unvoiced plosives.

I think people would similarily classify "Titi, Pipi, Touta, Poupa, Kouka" like "Kiki" but "Didi, Douda, Bibi, Gigi, Gouga" like "Bouba".

The vowels are obviously voiced by the vocal chord carrier wave "voice".

So when we pass through the unvoiced (T/P/K) plosives, we notice discontinuity like the discontinuously evolving tangents along the boundary curve of the figure.

Obviously mammals like dogs have a concept of continuity, topology, distance, they might get spooked by "open" stairs, because they can see between the planks, etc.

And when we hear voiced (D,B,G) plosives, the voice while muted still evolves continuously.

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CompoundEyes 44 minutes ago | parent | next [-]

Speaking of the topological intuition of mammals I guess “Boubas” are the big soft round ones and “Titis” are the firm pointy ones.

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po1nt 2 hours ago | parent | prev [-]

The question is how are you able to internalise the shape without ever seeing any visualisation. Why does the the bouba even evoke curvature?

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Wolfenstein98k an hour ago | parent | next [-]

Maybe because when you pronounce a B, it's very hard to make it sound sharp. The lips rolling off one another naturally have a gentle ramp-up. It's really hard to have a sudden transient. You can record this in a free DAW and see it in front of you.

By contrast, it's very hard to make a K- sound without a sharp transient.

With B you are adding pressure to two soft tissues in contact.

With K you are adding pressure when one tissue is hard, and saliva is present (causing a relatively sudden production of the sound).

Try making B sound sharp, hard to do while saying Bouba.

Try making K sound soft, basically impossible, especially while saying Kiki.

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D-Machine 2 hours ago | parent | prev | next [-]

Either similar underlying processing machinery (due to auditory and visual processing evolving from simpler and more interconnected processing circuits) or because when thinking of frequencies of waveforms in light/sound, visual sharpness and auditory sharpness really are the same thing (so even if they didn't co-evolve, it can be more efficient or useful to have some single underlying representation waveform representation that represents these things similarly).

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notahacker 2 hours ago | parent | prev [-]

tbf for me the Bouba evokes curvature because it makes me think of a Baobab tree. Not so sure about the dogs :)

	▲	WorldMaker an hour ago \| parent \| next [-]
		Part of the fun of the experiment is questioning the nominative determinism here. Did cultures pick a name like Baobab for that tree because of something this effect is showing or is just coincidence? We don't really know. Linguists have often wondered if there is a "universal grammar" underlying even our oldest languages that we don't know the full rules of, but coincidences and convergent evolution in our languages seem to tease could exist. Kiki and bouba are one of the more interesting experiments in this space to ever get repeatable results.
	▲	Wolfenstein98k an hour ago \| parent \| prev [-]
		Given the 100 years of studies across cultures (and now species), it probably made you think of curves shapes before you'd ever seen a boabob tree, let alone knew its name.