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Date of Award
Dissertation (On-Campus Access Only)
Doctor of Psychology (PsyD)
Sandra Jenkins, PhD
Empirical studies, naturalistic observations, and clinical work with twins all confirm the profound influence that twinship has on their psychology. This work presents an exploration of the unique aspects of psychological development in twins, from the viewpoint of contemporary relational models of psychoanalytic theory. A comprehensive review of the empirical literature on twin development reveals that they receive drastically reduced individualized contact with parents and poor attunement to their individual needs. Despite their disadvantaged start in life, twins have no more behavioral or emotional difficulties than singletons. In the face of inadequate parenting, twins turn to each other to find additional support and satisfaction of their interpersonal needs. My thesis is that twin infants and young children can engage each other intersubjectively, thereby providing much of the mutual affective communion normally observed between infants and caregivers. Infancy research has illuminated the inborn capacity of infants to distinguish themselves from others and to engage actively in emotionally meaningful interpersonal communication. An early, intense level of intimacy is facilitated by twins' prolonged, close contact, their similarities, genetically and developmentally, and their resulting capacity for reciprocity. This vital human connection protects twins from the worst sequelae of neglect and abuse, and profoundly affects their self development. Twin-twin interidentification, imitation, and complementing processes contribute to formation of a "we-self," with relatively diffuse boundaries between individual twin selves. Western cultural bias toward extreme autonomy, separation, and rigid boundaries between self and other has led to pathologizing of twinship. However, many non-Western cultures value ensembled individualism, where more fluid boundaries between individuals is the norm. Twinship can be considered a subculture characterized by interdependent connectedness. Evolutionary psychology also supports the notion of overlapping boundaries between related individuals, and predicts an intrinsic dialectical tension between individual self-interest and altruistic cooperation. Cooperation and competition are both adaptive behaviors, and for twins their balance tends toward greater cooperation, particularly for those who are genetically identical. Intersubjective theories of psychoanalysis and development are used to inform a synthesis of clinical, empirical, and observational information about twins, and to support twinship as a viable adaptation.
Trentacosti, Florence (1997). An intersubjective perspective on the development of self and object relations in twins (Doctoral dissertation, Pacific University). Retrieved from: