In this essay, it is argued that a general understanding of human development needs a unified framework based on evolutionary theorizing and cross-cultural and cultural anthropological approaches. An eco-social model of development has been proposed that defines cultural milieus as adaptations to specific socio-demographic contexts. Ontogenetic development consists of pathways along universal developmental tasks that have to be solved in culture-specific modes. Especially the emphasis of particular modes of autonomy and relatedness influence the timing, stability, dynamics, and gestalts of developmental processes. This argument is exemplified with results from a multicultural research program.