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Science In Action: 14/04/2011

14/04/2011

BBC World Service - Science In Action, 14/04/2011

Scientists track the distribution of sounds to discover how language evolved in Africa

How language came out of Africa, learning to see, how the brain switches from feeling to seeing and how the riderless bike stays upright.

Evolution of language
It has now been accepted by most people that humans evolved out of Africa. Now it seems the same is true for our ability to communicate by speech. Language is made up of distinct sounds and tones - known as 'phonemes'. These are similar to what genes are to the genome. By tracking the diversity and number of phonemes in different languages around the world, researchers have calculated that the most diverse and phoneme-rich languages are in Southern Africa and they get less diverse, the further away you get. 

Seeing and feeling
On regaining their sight, young people who were born with treatable blindness are initially unable to visually recognize an object that they have previously only touched. These results suggest that, in a sense, we must learn to see: people learn the correspondence between how objects look and how they feel, and this ability is not innate. 

How the riderless bike stays upright 
You might think that a bicycle is a fairly simple device, but to mathematicians, a bike provides a wealth of puzzles - from figuring out the mechanics of wheel rotation and friction to how they stay upright.  Now scientists have solved the equations as to why a bicycle with no rider can stay upright.  There is a number of different mechanisms that keep bikes upright and by designing a bike which rules out some of these, they have managed to work out what the other mechanisms are.  But will it mean the end to stabilisers?

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