The picture of infant experience suggested in this book has both differences from and similarities to the pictures currently drawn by psychoanalysis and developmental psychology. Since the approach I have adopted borrows methods and findings from developmental psychology and insights from clinical practice, it is important to discuss in greater detail the assumptions of each discipline and the problems of using both approaches together.

Developmental psychology can inquire about the infant only as the infant is observed. To relate observed behavior to subjective experience, one must make inferential leaps. Clearly, the inferences will be more accurate if the data base from which one is leaping is extensive and well established. The study of intrapsychic experience must be informed by the findings of direct observation, as the source of most new information about infants continues to be naturalistic