Johnson and Puplampu recently proposed the "ecological techno-subsystem", a refinement to Bronfenbrenner's theoretical organization of environmental influences on child development. The ecological techno-subsystem includes child interaction with both living (e.g., peers) and nonliving (e.g., hardware) elements of communication, information, and recreation technologies in immediate or direct environments. The theoretical techno-subsystem requires empirical validation. Parents of 128 children in first through sixth grade consented to cognitive developmental assessment of their children and completed questionnaires on children's use of the Internet at home and family socioeconomic characteristics. In general, indices of home Internet use accounted for more of the variance in children's cognitive development than did indices of socioeconomic status. The ecological techno-subsystem furthers our understanding of environmental influences on child development by emphasizing the impact of digital technologies on cognitive growth during childhood. (Contains 4 tables and 1 figure.)