Autism spectrum disorder (ASD) is a complex neurodevelopmental disorder that has been estimated to occur in 1.16% of children in the UK (Baird et al., 2006). It is characterized by substantial difficulties in social cognition, interaction, and communication (APA, 1994). In addition to these core deficits, ASD is associated with a wide range of more general impairments in many cognitive domains including, executive function (Hill, 2004), memory (Bennetto et al., 1996), attention (Allen and Courchesne, 2001), and perception (Simmons et al., 2009). An underlying etiology that links impairments across such an array of domains has not yet been identified. The literature on perceptual function is particularly puzzling, as while those with ASD show impaired performance of some tasks, e.g., detecting coherent motion within local motion noise (Milne et al., 2002), they show superior performance on tasks that involve detecting a target within a static array (Plaisted et al., 1998). Furthermore, enhanced and diminished perceptual sensitivity appear to co-occur, as Bertone et al. (2005) have demonstrated enhanced first-order contrast perception and decreased second-order contrast perception within the same group of participants.
