Developmental psychology is the scientific study of the life span of human beings. Communication scientists interested in the study of youth and media often use developmental psychology to help guide their understanding of how youth select, use, and experience media content. Grounded in developmental psychology, the moderate-discrepancy hypothesis has been used to understand developmental differences in the media use of children and adolescents. This hypothesis predicts that at, any given age, a moderate level of stimulus complexity is preferred and that this level increases as the child matures. The hypothesis has received reasonable support and continues to be one of the reigning developmental explanations for the changing media preferences that occur throughout childhood and adolescence. The integration of developmental psychology into communication science played a significant role in helping shift the field's perception of children from passive media consumers to active media consumers.