Mirror writing in typically developing children: A first longitudinal study

• At age 4 years, children rarely produce reversals when copying digits and letters.
• At age 5, the same children frequently reverse dictated left-oriented characters.
• An implicit right-writing rule explains this reversal of single characters.
• The rule depends on the direction in which the child writes (usually left–right).
• Complete mirror writing of names seems to begin as soon as writing begins.

The present study examined the development of mirror writing in typically developing children using a longitudinal design involving 166 children initially aged 4–5 years. The children were tested three times, with approximately one year between tests. The main predictions were that: (i) mirror copying of characters at T1 (4- to 5-years old) will be less frequent than mirror writing from memory at T2 (5- to 6-years old), (ii) an implicit right-writing rule—which holds that children orient single characters toward the right and hence most frequently reverse the left-oriented characters (e.g., 3, J)—explains well both character reversal at T2 and T3 and changes between T2 and T3 (6- to 7-years old), and (iii) name-mirror writing is possible as soon as children start learning to write.