Association Between Second to Fourth Digit Ratio with Handwriting Quality and Speed in Primary School Children

Authors

1 Assistant Professor, Department of Physical Education and Sport Science, Aliabad Katoul Branch, Islamic Azad University, Aliabad Katoul, Iran .

2 Assistant Professor, Department of Physical Education, Farhangian University, Tehran, Iran.

3 MSc, Department of Physical Education and Sport Science, Aliabad Katoul Branch, Islamic Azad University, Aliabad Katoul, Iran.

4 MD, Department of Physical Education and Sport Science, Aliabad Katoul Branch, Islamic Azad University, Aliabad Katoul, Iran.

Abstract

Background: Genetic influences on handwriting legibility and speed, especially in early childhood, are not well understood. This study used 2D:4D ratio as a biological marker to investigate associations between genetic factors with quality and speed of handwriting in primary school children.
Methods: Present study used a comparative-correlational method. Participants were 109 boys and 114 girls attending second and third grades in regular primary schools in 2019 in Golestan province, Iran. The Persian Handwriting Assessment Tool (Havaei et al. 2017) and photocopy method were used to measure handwriting performance and 2D:4D ratio, respectively. Legibility in copying and dictation as well as speed of handwriting were assessed as dependent variables.
Results: Results showed that boys and girls had identical age and education. Moreover, results revealed that boys in comparison to girls had significantly lower 2D:4D ratio in both right and left hands (P<.001). Furthermore, a negative association was observed between right 2D:4D ratio with word space in copying (r=-.23, P<.001) as well as a significant positive association between left 2D:4D ratio with word formation (r=.13, P=.04) in dictation in boys. Additionally, results indicated a significant negative association between right 2D:4D ratio with word alignment in dictation in girls (r=-.20, P=.02). No other significant associations were observed between 2D:4D ratio and handwriting performance. Finally, no significant differences were observed between boys and girls in handwriting performance.
Conclusions: 2D:4D ratio does not positively affect handwriting quality and speed in primary school children.

Keywords