How many people are left-handed?

Until the mid-20th century, left-handed people in many cultures, but particularly in industrialised, literate societies, were forced – or strongly encouraged – to use their right hands for manipulative tasks such as writing.

The arm which is used most has stronger muscles and its bones grow longer. Using this information, forensic archaeologist James Steele has looked at whether, with the cultural pressure taken off, more of the population will be lefthanded. In a survey carried out in the 1970s, only 3% of people aged 55-64 used their left hand for skilled tasks, compared with 11% of 15-24-year-olds. This higher figure for young people has been documented by taking radiographic measurements of the arm bones of adolescents.

Steele also measured the arm bones of medieval skeletons excavated in Yorkshire. He found that the number of left-handed people in the illiterate medieval population was similar to the late 20th-century figure.

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X-rays of a child's and an adult's hands
(Science Photo Library)

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