ABSTRACT
In this chapter, we discuss the development of eye movements toward targets detected in the periphery, or in the jargon typical of the literature on adults, the development of overt orienting toward exogenous stimuli (Klein, Kingstone, & Pontefract, 1992). Of prime interest are changes with age in the eccentricity from which targets can attract eye movements, or what has been called the measured visual field. Assessing the development of overt orieting toward exogenous stimuli is important for at least two reasons. First, peripheral stimuli guide shifts in visual attention. Thus, how well peripheral stimuli are detected influences how thoroughly babies search the visual world and which stimuli they bring to the fovea for more detailed examination. Second, the study of developmental patterns in overt orienting can provide insight into the development of underlying neural structures. We begin by discussing the methods that have been used to measure infants’ visual fields, the basic findings, and the variables that influence the measured visual field at any age. We then address the question of why babies’ performance improves with age, examining the influence of changes in peripheral sensitivity, in attention, and in other factors including motivation, optics, and the control of eye movements. Finally, we consider the neural mechanisms that may underlie the changes.
