Do differences in sex hormones affect handwriting style? Evidence from digit ratio and sex role identity as determinants of the sex of handwriting

Abstract This study investigated whether there could be a biological determinant of the judged gender of handwriting. It further investigated the potential interplay between these variables and sex role identification. The biological marker used was 2D:4D digit ratio (of index to ring finger length) which is negatively associated with prenatal testosterone and positively with prenatal oestrogen. Handwriting samples of 120 participants (half of each sex) were presented on computer to be rated for gender by 20 raters. Feedback on accuracy was given after each trial. These raters accurately identified the gender of two thirds of the sample and the rated difference between the sexes was large (d = 0.75). These ratings of handwriting gender correlated significantly with digit ratio and the femininity scale of the BSRI. A more conservative analysis this time within each sex found that women’s right hand digit ratio correlated with relative sexuality of handwriting, but there was no corresponding relationship for the males. These findings suggest that prenatal hormonal influences can affect later female handwriting performance and might even affect developmental inter-hemispheric differences, but do not appear to impact on males.