INTRODUCTION

Visual abilities undergo major transformation during infancy and childhood. Although infants arrive in the world both able to see and to learn about what they see, many aspects of vision and visual cognition continue to develop well into childhood (e.g., Chung & Thomson, 1995; Lewis & Maurer, 2005). Event-related potentials (ERPs) are a useful tool for investigating the neurophysiological correlates of these developmental changes as they can provide information not available from behavioral measures alone. In particular, they provide precise information about the timing and some information about the spatial distribution of the brain events underlying visual processing. Since ERPs can be obtained in “passive” tasks, where participants simply look at visual displays without any requirement to make a verbal or behavioral response, they allow use of the same procedure across a wide range of age and ability levels. For example, visual ERPs have been used to study face processing in infants only a few months old (e.g., Halit, de Haan, & Johnson, 2003) and have been used to investigate aspects of visual processing in children with various developmental disorders, including autism spectrum disorder (e.g., Dawson et al., 2002; Kemner, van der Gaag, Verbaten & van Engeland, 1999), Down syndrome (e.g., Karrer et al., 1998), and attention deficit-hyperactivity disorder (reviewed in Barry, Johnstone, & Clarke, 2003). Along with these distinct advantages, however, ERPs also present challenges both in terms of experimental design and data collection, and analysis and interpretation.