This first internal good object acts as a focal point in the ego. It counteracts the processes of splitting and dispersal, makes for cohesiveness and integration, and is instrumental in building up the ego.
Klein identifies the first introjected good breast as the structural anchor of the ego, whose felt integrity or fragmentation directly determines the degree of psychic coherence.
, Envy and Gratitude and Other Works 1946-1963, 1957thesis