Sibling differentiation, identity development, and the lateral dimension of psychic life
Last week in UK politics some commentators remarked how “brotherly love took a backseat to a lust for power” as the Miliband brothers competed against each other for the position of Labour party leader. Shortly after Ed took the crown David announced his decision to quit front bench politics. This competition has prompted observations regarding the dynamics of their relationship and inevitably their sibling rivalry.
From the time of Freud onward, the mainstream psychoanalytical view of sibling rivalry is that both are inherent to the human condition and infused with parental dynamics. This article examines sibling differentiation and identity development, recognizing how a child amplifies differences with siblings to reduce rivalry with them. Our relationship with siblings is structured around a particular psychic challenge: to find one’s unique place in a world of similar others.
The lateral dimension of psychic life, lived through relationships with siblings and their substitutes, is structured around a distinct psychic challenge: to find one’s unique place in a world of similar others. Like the challenge that structures the vertical parent-child dimension, the lateral challenge is fraught with conflict and ambivalence; its resolution imbues psychic structure. That resolution may be accomplished through a process of differentiation, an active and unconscious process of identity development by which a child amplifies differences with siblings and minimizes similarities. Differentiation from siblings serves to mitigate interpersonal rivalry with them and to ease internal conflict associated with the lateral dimension. Three clinical examples are offered to illustrate the operation of sibling differentiation and its costs, particularly in terms of constricted identity and attenuated relationships with siblings and peers. Differentiation as a process of becoming what the other is not has been eclipsed by identification in psychoanalytic theories of identity development. Yet differentiation is a common strategy for resolving the primary rivalries and conflicts of the lateral dimension, and has unique developmental and clinical implications.
Vivona, J. (2007). Sibling Differentiation, Identity Development, and the Lateral Dimension of Psychic Life Journal of the American Psychoanalytic Association, 55 (4), 1191-1215 DOI: 10.1177/000306510705500405