A study of 75 school children has shown that a photocopy of their hands is all that's needed to predict their literacy and mathematical skills.
Dr Mark Brosnan, from Bath University, measured the lengths of the index and ring fingers from images of the childrens' hands and compared the results to their SAT (standardised assessment test) scores. The results showed that the greater the length of the index finger relative to the ring finger, the better the subjects performed in maths, and lower the ratio the better their literacy skills.
Similar relationships have been found in the past for sporting ability, and scientists think that the relative lengths of the digits reflect the levels of hormones to which a developing baby is exposed in the uterus. The more testosterone there is floating around, the longer the index finger, and the team also think that testosterone could promote the development of brain areas linked to numerical and spatial skills. Oestrogen on the other hand is thought to do the same thing for those parts of the brain concerned with verbal ability. "We're not suggesting that finger length measurements could replace SATs," says Brosnan, "but finger ratio provides us with an interesting insight into our innate abilities in key cognitive areas".