Same-different letter decision task: a study with Spanish children with dyslexia (Tarea de decisión de letras igual-diferente: un estudio con niños españoles con dislexia)

ABSTRACT It is common to see mirror errors in letters in early stages of reading due to the mirror-generalization process that allows a visual stimulus to be identified independently of its orientation. To avoid such errors, this process must be inhibited. A special case would be children with dyslexia since their difficulties with the alphabetic code may also delay the acquisition of correct letter orientation. We investigated the relationship between reversible errors in reading and dyslexia. Twenty-seven Spanish-speaking children with dyslexia (7–12 years old) and 27 chronological-age-matched controls performed a ‘same-different’ letter decision task on reversible and non-reversible letters. Results showed that all participants required more time and committed more errors in discriminating reversible letters. In addition, worse execution was observed in the dyslexic group, which seems to indicate that this group is delayed in the acquisition of correct letter orientation. Therefore, our results indicated that overcoming reading errors in mirrors depends to some extent on the reading competence of the children and the ability to inhibit the process of generalization of mirrors.