Baby Chicks Match Sounds to Shapes Like Humans Do

Baby chickens just revealed something fascinating about how language might have started in the first place.

Italian researchers testing day-old chicks discovered these tiny birds instinctively match nonsense words to shapes the same way humans do. When they heard "bouba," the chicks moved toward rounded, blob-like shapes. When they heard "kiki," they preferred spiky, jagged ones.

This association, called the bouba-kiki effect, appears in people worldwide regardless of culture or language. Even four-month-old human babies show the same preference, linking soft sounds to soft shapes and sharp sounds to sharp shapes.

What makes this discovery remarkable is that scientists couldn't find this effect in our closest relatives. Studies of chimpanzees and gorillas came up empty, making researchers wonder if this ability was uniquely human.

Maria Loconsole and her team at the University of Padova decided to test animals that could be studied right after birth. With chicks just one to three days old, they could be certain any results reflected innate abilities rather than learned behavior.

The researchers first trained three-day-old chicks to find food behind a panel decorated with both rounded and spiky shapes. Once the chicks learned this game, the scientists presented them with two panels, one spiky and one rounded.

During this moment of uncertainty, they played either "bouba" or "kiki" sounds repeatedly. The chicks consistently chose the rounded shape for "bouba" and the spiky shape for "kiki."

Marcus Perlman, a linguistics researcher at the University of Birmingham who wasn't involved in the study, admits he's surprised. "If I had to guess whether baby chickens would exhibit the bouba-kiki effect, I would have guessed no," he says.

Why This Inspires

This discovery suggests something profound about how communication evolved. The ability to link sounds with meaning didn't just appear in humans out of nowhere.

Instead, it reaches back hundreds of millions of years to a common ancestor of birds and mammals. Our sensory systems evolved to expect certain patterns in the world, like high-pitched sounds matching small objects and low-pitched sounds matching large ones.

These hard-wired connections became the foundation humans built language upon. While chicks don't have language, they share the same basic perceptual links that helped our species create spoken words.

What truly sets humans apart isn't these associations themselves but our creative ability to generate endless new symbols. We can use sounds, gestures, and drawings to play an elaborate game of charades that no other animal matches.

The research, published in the journal Science, opens new questions about how deeply rooted our communication abilities really are and what other animals might share these ancient perceptual patterns with us.