This paper describes research conducted over the past twenty years that was informed by Winnicott's thinking on the importance for child development of the early mother—infant relationship.

The first part of the paper sketches the different approaches taken by researchers in developmental psychology in the 1970s to infant communication; these reductionist accounts stand in marked contrast to Winnicott's view of the infant as seeking personal engagements. This is followed by an outline of studies employing brief experimental perturbations, or impingements, to maternal communication with the infant, work that demonstrates the striking sensitivity of infants under 3 months old to their interpersonal environment.

The second part of the paper describes research on the development of children whose mothers were depressed in the postpartum period. This work shows how different aspects of mother-infant interactions are associated with different kinds of child developmental outcome.