Digit ratio as an indicator of numeracy relative to literacy in 7-year-old British schoolchildren.

A great deal of recent research has focused upon the relationship between a hypothesized index of prenatal testosterone exposure, digit ratio and health, social and cognitive functioning. Many inconsistencies within the pattern of findings have been identified in the relationship between digit ratio and absolute levels of cognitive ability. Recent research has identified a relationship between digit ratio and basic numeric competency. This basic numerical competency has been argued to be influenced by biological factors. The present study extended this finding to academic assessment, namely the Standardized Assessment Tests undertaken in numeracy and literacy by children in the UK at the age of 7. The present study hypothesized that digit ratio would correlate with the relative difference between numeracy and literacy abilities. Digit ratios were calculated for 75 (mainly Caucasian) children aged between 6 and 7 attending a state funded infant school. The digit ratios were then correlated with the results from their National Standard Assessment Tests (SATs). A significant correlation was found as hypothesized. Additionally, there was a negative correlation between digit ratio and numeracy for males (indicating higher prenatal testosterone exposure related to higher numeracy SAT scores) and a positive correlation between digit ratio and literacy for females (indicating lower prenatal testosterone exposure related to higher literacy SAT scores). These effects were small and the implications for using digit ratio to facilitate understanding of hormonal influences upon academic attainment are discussed.