London : The length of index and ring fingers could predict how well your children will do in mathematics and literacy if he or she is seven years old, shows a new study.
Specifically, boys whose index fingers were short compared with their ring fingers may excel at numbers and girls with index and ring fingers of similar length also may do better, the research indicates.
Scientists led by Dr Mark Brosnan, Head of the Department of Psychology at the University of Bath, compared the finger lengths of 75 children with their Standardised Assessment Test (SAT) scores.
In the study that will be published in the British Journal of Psychology they found a clear link between a child's performance in numeracy and literacy tests and the relative lengths of their index (pointing) and ring fingers.
Scientists believe that the link is caused by different levels of the testosterone and oestrogen hormones in the womb and the effect they have on both brain development and finger length.
"Testosterone has been argued to promote development of the areas of the brain which are often associated with spatial and mathematical skills," Brosnan, said.
"Oestrogen is thought to do the same in the areas of the brain, which are often associated with verbal ability and interestingly, these hormones also have a say in the relative lengths of our index and ring fingers," he added.
The researchers made photocopies of the palm of the children's hands and then measured the length of their index finger and ring finger on both hands using calipers, a measuring instrument accurate to 0.01mm.
They then divided the length of the index finger by that of the ring finger – to calculate the child's digit ratio.
When they compared this ratio to the children's SAT scores, they found that a smaller ratio (i.e. a longer ring finger and therefore greater prenatal exposure to testosterone) meant a larger difference between ability in maths and literacy, favouring numeracy relative to literacy.
The scientists also looked at the boys' and girls' performance separately and found a clear link between high prenatal testosterone exposure, as measured by digit ratio, and higher numeracy SAT scores in males.
They also found a link between low prenatal testosterone exposure, which resulted in a shorter ring finger compared with the index finger, and higher literacy SAT scores for girls, according to health portal Medical News Today.
The scientists suggest that measurements of finger length could help predict how well children will do in mathematics and literacy.