Baby chicks pass the ‘bouba-kiki’ test, challenging a theory of language evolution
Hacker News
February 19, 2026
AI-Generated Deep Dive Summary
Newborn chicks have demonstrated an ability to associate specific sounds with particular shapes—exhibiting behavior remarkably similar to humans in the "bouba-kiki" effect. This phenomenon, where certain sounds like "bouba" feel round and "kiki" seem spiky, has long been considered a clue to understanding how early language developed. However, a new study published in *Science* reveals that baby chicks make the same sound-shape connections, challenging previous theories about the uniqueness of human language.
The research conducted by Maria Loconsole and her team at the University of Padua involved placing newborn chicks in front of two objects: one rounded and curved, the other spiky. When played recordings of "bouba" or "kiki," the chicks consistently showed preferences matching these sounds to their corresponding shapes—80% approached the round shape when hearing "bouba," and similarly for "kiki" paired with the spiky shape. Importantly, this behavior was observed within hours after hatching, before any environmental influence could have shaped their responses. This suggests an innate perceptual bias deeply rooted in evolutionary history.
The findings challenge earlier theories that attributed the bouba-kiki effect to uniquely human linguistic capabilities or cultural influences. Previous studies with great apes yielded mixed results, with some failing the test while others succeeding but possibly due to prior training. Loconsole argues that these early experiments may have introduced biases, whereas the chicks' responses were untainted by experience.
The study's implications are profound for understanding the origins of language and perception. If such sound-shape associations are hardwired in both humans and birds, it hints at a much deeper evolutionary history than previously thought—potentially dating back to a common ancestor some 300 million years ago. This raises questions about how and why certain sounds came to represent specific meanings in early language systems.
For tech enthusiasts, this research opens new avenues for exploring the relationship between perception and communication, particularly in AI and human-computer interaction. If these associations are biologically ingrained, they could inform the design of more intuitive interfaces or even shed light on how humans process meaning at a fundamental level. The study also underscores the importance of revisiting long-held assumptions about language evolution, emphasizing that human linguistic abilities may not be entirely unique but rather built upon
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Originally published on Hacker News on 2/19/2026