Mirror writing of digits and (capital) letters in the typically developing child.

Typically developing 5- to 6-year-old children often reverse some digits (e.g., ɛ for 3) or single (capital) letters (e.g., Я for R) when they are required to write them under dictation. A theoretical approach to this phenomenon, based on an implicit right writing rule and that postulates an influence of the preceding writing, was tested in an experimental study of 300 children aged 5-6 years. The data support the implicit right writing rule and show the considerable influence of the preceding writing. For example, 73% of the children who correctly wrote the letter C mirror wrote an immediately following digit 3, whereas only 10% of the children who mirror wrote the letter C also mirror wrote an immediately following digit 3.