Recent studies looking into the development of mental precursors link the acquisition of the Theory of Mind to the previous appearance of symbolic play. When performing symbolic play tasks, the development of causal reasoning skills represents a differential factor, which is essential to the subsequent acquisition of the Theory of Mind. A total of 45 children (24 boys and 21 girls), aged between 24 and 39 months (with a DQ of 58-69), diagnosed with different conditions (delayed cognitive development, delayed language development and/or Pervasive Developmental Disorder). The aim of the study is to analyse the relation between mental precursors and different disabilities. The results show that the most widely affected mental prerequisite was found to be the development of Symbolic Play, which is directly related to the development of causal reasoning. No significant differences based on the type of condition were detected. The evidence has shown that the development of mental precursors is not a uniform process. It would therefore be recommendable to offer specific training in the development of mental precursors related to the development of causal reasoning.
Keywords: Mental precursors, pre-verbal communication, Symbolic Play, socio-cognitive skills, training in premental skills.