Developmental abilities and disabilities in the processing of information are being studied from three viewpoints: First, an investigation of the development of the ability to encode various properties of information, both verbal and nonverbal. Second, an examination of the possibility of a maturational lag in the development of hemispheric assymetry. Third, a exploration of possible deficits in the ability to discriminate amongst sounds of speech. Proposed specifically for the coming year are test of retention of nonverbal figures, and of motor movements that cannot be mediated verbally. Also we plan to study hemispheric specialization for nonverbal materials using dichotic presentation of nonspeech sounds. Finally, we plan to investigate the role of interference on the retention of verbal material by manipulating the type of distractor activity that intervenes between presentation of the material and eventual recall.