Psychological Weaning in Rodents: A Developmental Framework for Emotional Independence

Psychological independence from parental figures is a core developmental milestone across social mammals, yet its timing and mechanisms vary markedly across species. Physical weaning terminates nutritional dependence but does not necessarily coincide with emotional autonomy. In humans, psychological weaning unfolds across childhood and adolescence. In contrast, rodent data indicate that key elements of psychological detachment can emerge during the lactation period itself. Here, we synthesize behavioral, neurobiological, and evolutionary findings to propose a four-phase developmental framework of psychological weaning in rodents, anchored primarily in mouse data. During a restricted late-lactation window, maternal absence can transiently acquire positive emotional valence in a sibling-dependent manner, promoting detachment despite continued access to maternal milk. Integrating attachment models with evidence for peer-based social scaffolding and post-weaning prefrontal maturation, we argue that psychological weaning reflects a developmentally regulated redistribution of social value from maternal to peer contexts. Revisiting parent–offspring conflict theory, we propose that offspring-initiated reorganization of emotional valuation may facilitate independence without overt conflict. Together, these findings reconceptualize psychological weaning as an active, temporally gated transition in social valuation, establishing rodents as a powerful model for dissecting the circuit mechanisms that govern emotional independence.