Research on childhood in anthropology and neighboring disciplines has continuously broadened the range of the social partners that are considered relevant for young children's development-from parents to other caregivers, siblings, and peers. Yet most studies as well as interventions in early childhood still focus exclusively on parents, who are presumed to be the most significant socializing agents. Objecting to such a hierarchical understanding of the social world of children, I propose a complementarity view. Rather than being linearly ranked in a hierarchy of significance, children's social partners may complement each other by providing different but equally significant experiences. My suggestions are based on an ethnographic study in a rural community in Madagascar. Focusing on children in the first 3 years of life, I explore the full range of their social partners and the respective experiences they provide. Caregivers focus on children's physical needs and aim to keep them in a calm emotional state, while other young related children are the most crucial partners when it comes to play, face-to-face interaction, and the exchange of intense emotions. These complementary roles, I argue, lead to the parallel formation of two distinct socioemotional modes: a hierarchical one and an egalitarian one.Parents are usually considered the most influential figures in young children's lives and development-in research as well as in early childhood policies and interventions. Global endeavors to improve early childhood development, for instance, which have become a booming sector of international development in the past three decades, are mostly directed at parents or caregivers. UNICEF's program Care for Child Development, to take one prominent example, claims on its website that "over 200 million children . . . do not reach their full human potential." As a solution, the program aims to train parents and caregivers "to focus on the most important activities for the development of young children-play and communication." 1 These claims are derived from a series of three articles in the Lancet that identify "inadequate cognitive stimulation" as a major risk for children under 5 years of age in so-called developing countries (Walker et al. 2007:153). As evidence, the authors state that only a minority of parents in these countries "provide cognitively stimulating materials to their child" or "actively involve their children in cognitively stimulating activities" (153). The corresponding interventions they refer to were all directed at mothers or parents and consisted mainly in training them how to play or talk with their children (151). 2 This is but an example of a widespread parent-centric approach to early childhood research and intervention. It is based 1. https://www.unicef.org/earlychildhood/index_83036.html (accessed March 31, 2020).2. For critical perspectives on early child development interventions