ABSTRACT
On the interpersonal level we may notice the pairing of two siblings. The siblings may or may not be biological twins; biological twinship is not a necessary condition for twinning. As in the situation of deposited representations, the mother's or adult caregiver's conscious, but more importantly, unconscious fantasies play a role in the development of twinning between siblings. Because the term twinning sounds like biological twinship, it might make sense to consider using another term in order not to confuse pathological intrapsychic self and object relationships with the relationships between actual twins. In the general psychological literature there are a great many papers on the psychology of twins, basically exploring the question of nature versus nurture. Because of their genetic makeup, twins provide a real opportunity for examining genetic variables in human development.
