This research program is designed to elaborate the relationships among intelligence, speed of information processing, academic achievement, and various forms of deafness. The research is primarily interested in developing a better understanding of why deaf children of deaf parents outperform deaf children of hearing parents (and normal-hearing children) on tests of nonverbal intelligence. Additionally, the investigations will address issues related to shared and unique environmental and genetic influences on intelligence, speed of information processing, and achievement in subgroups of deaf children believed to be genetically deaf. The proposed activities are a direct outcome of research the PI has conducted in the past with groups of deaf persons using intelligence tests and speed of information processing techniques. The subproject proposes a series of integrated investigations, which will address the following questions: 1. Are deaf children of deaf parents (DP), and deaf children of hearing parents with a deaf sibling (HP/DS), superior to other deaf (HP) and normal-hearing children on a variety of intellective tasks, or only on some intellective tasks? 2. Are above average IQs of DP and HP/DS due to factors shared by family members, or are above average IQs unique to deaf children within families? 3. Are speed of information processing tasks sensitive to prior exposure to language, and/or sensitive to practice effects? 4. Is there a relationship between automaticity of elementary cognitive processes involved in reading and reading rate? 5. Are longitudinal changes in intelligence related to speed of information processing?