Genes do not by themselves produce structural or functional characteristics. Variables within the organism (e.g., cells, tissues) and extraorganism contextual variables reciprocally interact with genes, making changing organism-context relations the basic process of development. This conception of basic process raises 2 sets of conceptual and methodological alterations for developmental psychology, especially for research pertinent to humans. First, research questions must be formulated that involve intra- and extraorganism contextual relations and that are necessarily multidisciplinary in scope. Second, greater research sensitivity must exist to issues of contextual variability, to diversity in human life and development, and to interindividual differences in the timing of organism-context interactions. Scholars must develop empirically generative models that link integratively developing people with their changing contexts.