A computational model is proposed for the early stages of development of the object concept in infants. Stages in development are represented as a sequence of grammars or rewrite rules parsing a set of perceptual phenomena. The infants' changes between developmental stage; can be described by differences between the grarrmar rules modelling each stage. The program replicates five Bower et al studies on the development of the object concept and reaffirms the primacy of rest and motion parameters as explanatory invariants in early object concept development.