Bulletin of the Philadelphia Association for Psychoanalysis. X, 1960: Observation on Ego Development: The Birth of a Sibling. Yvon Gauthier. Pp. 69-85.

Gauthier presents extensive observations made on his three children, aged three, two, and one, before and after the birth of a fourth child in the family. The three-year old displayed anticipatory anxiety, whereas this was not so with the other two. The two older children showed varied regressive tendencies, although the older was able to develop a more adequate defense system and suffered less. The patterns of behavior which the two older children developed have persisted beyond the period of acute trauma. The reaction of the youngest child, while seeming to indicate some sense of loss with respect to the mother, was not so well defined. From these observations, the author suggests that the reaction of a child to the birth of a sibling is influenced by the level of his ego development at the time. The ability to anticipate and prepare comes with a more highly developed ego and minimizes the traumatic influence of the event. The level of regression is influenced by fixations established by previous trauma. The defensive patterns developed to such trauma as the birth of a sibling seem to be of a sort that would have profound effects on the formation of psychic