It is argued that the theoretical framework used in earlier studies of children's use of the articles is inadequate, failing in some important ways to capture even normal adult usage. A new theory of article usage is proposed which is based on the concept of mental models. Previous psychological investigations are evaluated in the light of this theory and the major issues raised are investigated experimentally. Nine experiments involving approximately 310 three to seven-year old children and 65 parents are reported. The experiments were designed to investigate the effects of two main factors on children’s use of the articles, namely, the knowledge of the listener and the composition of the referential array. Different kinds of tasks were employed which required responses varying from article plus noun to single sentences and extended narratives. The results of the experiments showed that although young children can, and do, take into account the status of an object within a referential array, the over-riding factor in their choice of referring expression is their perception of the knowledge of the listener. When they judge that the listener's model does not contain the same number and kind of objects as their own (the listener is ignorant), children will use an indefinite description to introduce a referent regardless of the status of that referent in the array. However, when the listener is knowledgeable indefinite descriptions are reserved for one of several identical or similar objects and definite descriptions are used for objects which are known to be unique in the listener's model. Other factors which influence children’s use of the articles include the difficulty of the task, the child’s perception of the purpose of the task, and the range of descriptions in the child's linguistic repertoire
