Comparative Psychology
Baby chicks pass the bouba-kiki test challenging a theory of language
Newborn chicks connect sounds with shapes just like humans, suggesting the bouba-kiki effect has ancient evolutionary origins that predate language development.
Imagine you hear the made-up words "bouba" and "kiki" - which one sounds round and soft, and which sounds sharp and spiky? Most people say "bouba" sounds round and "kiki" sounds sharp. This is called the bouba-kiki effect, and scientists thought it might be special to humans and related to how we developed language. But this study found that baby chickens, just hours after hatching, make the same connections! When they heard "bouba-like" sounds, 80% of the chicks walked toward round, curved shapes rather than spiky ones. This suggests that connecting sounds with shapes isn't learned or uniquely human - it might be a basic way that many animals' brains work, going back hundreds of millions of years in evolution.
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Newborn chicks demonstrated the bouba-kiki effect, associating rounded sounds with curved shapes and sharp sounds with spiky shapes, with 80% of chicks approaching the round shape when hearing 'bouba'
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The sound-shape associations were observed within hours of hatching, indicating an innate perceptual bias rather than learned behavior
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The findings suggest the bouba-kiki effect has deep evolutionary roots dating back at least 300 million years to when birds and humans diverged
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Unlike great apes who failed similar tests, chickens successfully demonstrated cross-modal sensory connections between auditory and visual stimuli
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The research challenges the theory that the bouba-kiki effect is uniquely human and specifically linked to language evolution