The objective of our investigation was to obtain a more profound knowledge of the characteristics of thought in children with Retention of the Psychical Development, establishing wether or not there exist a differential subgroup within enabled us to make a comparative analysis normal children. We believe in the necessity of this work from a theoretical standpoint, namely the establishment of a precise category of this particular importance its manifestations in Cuban children. Clinically speaking, there is a practical necessity of a correct and precocions diagnosis of the cases, determining if these children all develop in the same way, thus eliminating if the possibilite of an erroneous evaluation which could bring serious psychological, pedagogical, clinical, ethical and social consequences. Our investigation was directed to two groups of 25 children of 7-9 years old inclusive, one of which consisted of children with psychical retention and the other of normal children. The results were analysed by statistical methods and computer programs: it was found that there are differences in thougth characteristics among the RDPs which confirm the presence there of a differential subgroup.