Visual supports in the form of communication boards, schedule boards, and color-coded educational materials are commonly used to facilitate learning, comprehension, and communication. In particular, these supports are central components of augmentative and alternative communication (AAC) intervention in speech-language pathology, which is designed to supplement spoken communication for people with limited speech. These supports depend on vision, and different populations differ in their ability to extract and process visual information. However, no systematic evaluation of the impact of basic principles of visual perceptual processing on the design of visual AAC symbols and symbol presentation formats has been conducted. This project seeks to fill the information gap by examining how basic neuroscience research on visual-perceptual processing on children with autism and Down syndrome may be exploited to enhance the design of visual supports used in clinical, educational, and rehabilitative interventions.