Social environments shape behavior and neurobiology across the lifetime. This phenotypic shaping is a dynamic process that involves sequences of distinct social environments across stages of development. Unfortunately, research on the environmental effects on brain development and behavior too often focuses on individual periods of life. This prevents an understanding of how sequences of life stages could interactively shape phenotypes over developmental time. Here I first describe the development of oxytocin and vasopressin receptors in the prairie vole (Microtus ochrogaster) and demonstrate the influence of juvenile social and spatial enrichment on brain development. These developmental trajectories and their responses to enrichment are highly region-specific, and somewhat sex-specific. Notably, the general patterns of trajectories for oxytocin receptors (OTR) and for vasopressin receptors (V1aR) are highly distinct. Enrichment results in a male-specific reduction of V1aR across several brain regions, whereas OTR is strictly promoted following enrichment. I then demonstrate the interactive impacts of perinatal and juvenile social environments on oxytocin and vasopressin receptor development and social cognition. Male prairie voles that experience a two-hit model of social deprivation (single-mother rearing + social isolation) develop higher oxytocin and vasopressin receptors in specific regions, and also develop impaired social discrimination. Lastly, I provide support for how perinatal and juvenile social environments can interact to influence the behavioral effects of intranasal oxytocin. Males experiencing a two-hit model of social deprivation (single-mother rearing + social isolation) engage in promoted alloparental care behavior towards novel neonatal voles. Taken together, this research highlights the influence of interactive effects of consecutive social environments on neurobiology and behavior, and emphasizes the importance of considering multi-factorial dynamics on the developmental process in future studies.