ABSTRACT
This chapter explores the evolving understanding of infancy from the perspective of the most research into infant capacities and interpersonal behaviour, and the effects of human neurobiology on these emerging capacities and behaviours. There are structures at every biopsychosocial level—cells, brains, bodies, dyads, families, cultures—that prepare and organise life in relationship with other people who recognize, respond, and communicate together. Peter Fonagy, P. Luyten, and L. Strathearn have identified a complex relationship between the neurobiology of attachment, the capacity for mentalisation, and stress reactivity. The infant of developmental neuroscience and modern psychoanalysis is, from birth, a social being who is attuned, intersubjective, and intentional. Two neuropeptides—oxytocin and vasopressin—have been implicated in a number of affiliative responses in both animals and humans, including pair-bonding, mating, maternal (care-giving) behaviours and attachment. The cortisol-mediated stress system operates from birth. Infant temperament, the quality of care-giving and the interactions between temperament and care-giving affect the reactivity of the stress system.
