Humans need other people to survive and thrive. Therefore, relatedness is a basic human need. However, relatedness can be conceived of very differently in different cultural environments, depending on the affordances and constraints of the particular context. Specifically, the level of formal education and, relatedly, the age of the mother at first birth, the number of children, and the household composition have proven to be contextual dimensions that are informative for norms and values, including the conception of relatedness. Higher formal education, late parenthood, few children, and a nuclear family drive relationships as emotional constructs between independent and self-contained individuals as adaptive in Western middle-class families. The perspective of the individual is primary and is organized by psychological autonomy. Lower formal education, early parenthood, with many children, and large multigenerational households, drive the conception of relationships as role-based networks of obligations that are adapted to non-Western rural farm life. The perspective of the social system is primary and organized by hierarchical relatedness. Social development as developmental science in general, represented in textbooks and handbooks, is based on the Western middle-class view of the independent individual. Accordingly, developmental milestones are rooted in the separation of the individual from the social environment. The traditional rural farmer child’s development is grounded in cultural emphases of communality which stress other developmental priorities than the Western view. Cross-cultural research is mainly interpreted against the Western standard as the normal case, but serious ethical challenges are involved in this practice. The consequence is that textbooks need to be rewritten to include multiple cultural perspectives with multiple developmental pathways.