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.

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.

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.

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.

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.

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 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

What's the N value of this study

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.

baba is keke

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

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