Multiple object tracking in infants: Four (or so) ways of being discrete

It has been reported that infants represent the continued existence of an object through occlusion and they can track even multiple objects. Many studies have found that infants track the discrete numerosity of small sets of objects in multiple modalities, but the interpretation of these findings remains controversial. In this chapter, the authors evaluate the available evidence for four theories that have been proposed to explain how infants track discrete quantity namely: object indexing, sets, mental magnitudes/accumulator, and integers. Of the four theories, only the accumulator and the generative integer views posit an irreducibly numerical basis to infants' number representations. The object indexing and set accounts provide a mechanism by which infants might be able to track small numbers of discrete objects and compare them on the basis of their numerical identity without actually being able to count.