The neurobiology of human allomaternal care; implications for fathering, coparenting, and children's social development.

Allomothering, the caregiving to offspring by adults other than the biological mother including fathers and other group members, has characterized human societies throughout hominin evolution. Allomothering is common across the animal kingdom and carries long-term fitness benefits to offspring. Guided by our biobehavioral synchrony conceptual frame, we present research from our lab and others addressing the behavioral, hormonal, and neural systems that underpin human allomaternal care by fathers and studies on the coparental bond. Several important aspects of human allomothering are discussed: (i) father-child synchrony, (ii) longitudinal effects of fathering and coparenting on child outcomes (iii) cultural variability in paternal care, (iv) the role of oxytocin, vasopressin, prolactin, and testosterone in the formation and maintenance of human fathering, (v) evolutionary changes in fathers' brains within the parent-offspring interface and their contribution to children's long-term social adaptation, and (vi) the neural correlates of human coparenting. Based on our findings we propose that in the course of hominin evolution fathers' neuroendocrine systems, brain functionality and integrity, and behavioral responses to infant cues have undergone profound natural selection to accommodate the great variability in the paternal role across time and place, culminating in the contemporary cooperative, highly involved coparent observed in modern societies of the developed world.