Selective Effect of Inhibition of Literal or Numerical Irrelevant Information in Children With Attention Deficit Hyperactivity Disorder (ADHD) or Arithmetic Learning Disorder (ALD) Maria Chiara Passolunghi Department of Psychology University of Milano-Bicocca, Italy Gian Marco Marzocchi Department of Psychology University of Milano-Bicocca, Italy Cognitive Psychology Unit IRCCS Medea Bosisio Parini–Lecco, Italy Francesca Fiorillo Department of Psychology University of Trieste, Italy This study investigated reasons why children with attention deficit hyperactivity dis- order (ADHD) or arithmetic learning disorder (ALD) have difficulties in solving arithmetic word problems. In particular, the aim of this study was to verify whether these difficulties are due to a working memory deficit and defective inhibition of ir- relevant information included in the problem wording. Furthermore, the study was geared to test whether children with ADHD or ALD have a specific disability in re- calling and handling numerical or literal information. In an attempt to provide an an- swer to these questions, three groups of children were tested: children with ADHD, DEVELOPMENTAL NEUROPSYCHOLOGY, 28(3), 731–753 Copyright © 2005, Lawrence Erlbaum Associates, Inc. Requests for reprints should be sent to Maria Chiara Passolunghi, Department of Psychology, Uni- versity of Milano-Bicocca, P. Ateneo Nuovo, 1, 20126 Milano, Italy. E-mail: mariachiara.passolunghi@unimib.it