Sex differences in lateralisation of fine manual skills in children.

One hundred and twelve children (55 boys and 57 girls) were tested using two tasks taken from the Movement Assessment Battery for Children. The girls had a larger between-hands asymmetry than boys on the threading nuts on bolt task, thus indicating they were more lateralised. On the other task, placing pegs, no such sex differences were found. We present our findings as a warning to others that even though two tasks are assumed to measure the same, in this case unimanual performance, differences in task constraints will exist. Such differences may constitute a confounding factor when trying to infer about lateralisation based on behavioural tasks.