This article is from the Psychology FAQ, by Rolf Marvin Bøe Lindgren email@example.com with numerous contributions by others.
Otto Kernberg has postulated a theory of BPD based on a phenomenon he
describes as splitting. It is based on a psyhcoanalytical theory
known as object relations theory. I feel that his treatment makes
sense whether one does believe in psychoanalysis or not. If you know
of a better model, please tell me.
An object in object relations theory is an individual who is
emotionally important. an individuals first objects are his or her
parents; later, other members of the family, friends, lovers, etc.
become objects in this sense.
To the infant, objects are his or her perceptions of other people,
and there is one object for each important set of emotions related to
each person. So a mother, say, is split in the infant's mind into a
good mother who provides food and shelter, and a bad mother who
provides punsishment or just a feeling of absence when she's not
there. Part of an individual's development consists in merging these
fragmented objects into more complex objects which provide a truer
intuitive model of the individual. Maturity means, among other things,
being able to perceive an individual in terms of all of his or her
traits. An mature person views the punishing and the rewarding mother
as two aspects of the same individual.
An immature person, however, views the punishing and the rewarding
mother as two separate objects. An a person who's in love will only
perceive the good object of his or her affection, and normally for a
while at least be unable or highly unwilling to perceive the rest.
This phenomenon is known as splitting, and is considered a very
immature defense mechanism.
Splitting appears to be the main defense mechanism of the borderline.
A borderline perceives people in terms of black and white or as either
good or bad objects. The main problem in handling borderlines is to
cope with their unrealistic views of other people - and in their
attempts to create self-fulfilling prophecies to make the world fit
with his or her perceptions. If a borderline perceives you as a good
object, he or she will go to greath lengths in providing situations or
interpretations compatible with this view.