Evolutionary Biology

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.

Imagine your nerve cells are tiny workers in a factory that runs all day. As they work, they make a small mess and sometimes break their tools (this is like DNA damage). Sleep is like the night-time cleaning and repair crew. It shuts down the main factory operations so the crew can come in, clean up the mess, and fix the broken tools. This study looked at the simplest, oldest factories in the animal kingdom—jellyfish and sea anemones—and found that they also need this nightly repair crew. When they were forced to stay 'awake,' the mess and broken tools piled up. This suggests that the need for a dedicated repair shift (sleep) is a very old and essential part of being an animal.