Emotions are complex processes that are essential for survival and adaptation. Recent studies of children and animals are shedding light on how the developing brain learns to rapidly respond to signals in the environment, assess the emotional significance of this information, and in so doing adaptively regulate subsequent behavior. Here, I describe studies of children and nonhuman primates who are developing within emotionally aberrant environments. Examining these populations provides new insights on the ways in which social or interpersonal contexts influence development of the neural systems underlying emotional behavior.