In recent years, interest in the development of perceptual, memory, and attentional processes in infants and children has burgeoned. A great deal of this work has been spurred by technological advances and by the development of new experimental paradigms that have made it possible to explore infants' abilities and limitations in these areas (Cicchetti & Wagner, in press). Such research has underscored the importance of examining these basic capacities in elucidating how individuals perceive and understand their world. As a result, our knowledge of the processes and mechanisms that underlie cognitive development during these periods has increased dramatically.

In this chapter, we focus upon perception, attention, and memory in infants and children with Down syndrome. Consequently, we review studies that have utilized nontraditional assessments of these abilities. We have adopted a developmental framework in our discussion of these abilities because we are interested in the ontogenesis and interactions of psychological processes over developmental time. Historically, most of the previous reviews and research on Down syndrome has been characterized by an a-developmental approach. In general, Down syndrome samples and normal or other mentally retarded groups of similar mental or chronological age have been compared at a single point in time. True developmental studies have been infrequently conducted because it is difficult to collect data from sufficient numbers of children with Down syndrome at several different ages and to examine them longitudinally. Additionally, another difficulty in longitudinal studies with this population resides in the controls: Over time normal controls become inappropriate owing to their accelerated rate of development.