Personality Development in Identical Twins

Abstract

There has been a resurgence of interest in the role of heredity in mental illness. Current psychiatric twin research has emphasized the statistical comparison of large groups of uniovular and biovular twins with respect to concordant and discordant characteristics. Kallmann's book¹ gives the history and philosophy of genetics in psychiatry as well as a summary of his work in this field. Slater's publications^2,3 on twins presents his research as well as tracing psychiatric twin studies from Francis Galton to the present. Psychological investigations of intelligence and personality by earlier workers were summarized by Woodworth⁴ in 1941, although several papers^5-13 have appeared more recently. A comprehensive review of behavior genetics by Fuller and Thompson¹⁴ appeared in 1960. Several psychodynamic views^15-17 of the personality development of twins have been published. They emphasize a study of heredity versus environment and the