An explicit model of the process of quantification which involves the operations of subitizing and counting is described. The general model states that quantification of n items takes place via subitizing when n is less than five and via subitizing and addition (that is, counting) when n is five or larger. The explicit model is stated in the form…

Experiments dealing with quantification processes in adults were run as part of an attempt to formulate an information processing model of cognitive development. The existence of three quantification operators--subitizing, counting and estimation--was first postulated. Experiments were then designed to refine the parameters which define the…

An analysis of the quantitative processes underlying conservation of quantity is presented. Models of three quantitative operators--subitizing, counting, and estimation--are derived from adult performance in quantification tasks, and some features of the operators are described. The emergence of conservation is described in terms of the…