[Child development: primary influences, primary stages and foundations of psychotherapy]

Recent research on child development and on infant-mother psychotherapy is reviewed. The problem of continuity or discontinuity of early patterns is thus brought out, as well as the possibility of change under the influence of environmental modifications or in psychotherapy. After briefly presenting the most often proposed mechanisms to explain change, the possibility is suggested that such change could be better conceptualized by using fundamental modes of development that can be particularly observed in mother-infant or parent-young child interaction.