Nature/nurture: development is a combination of the two, for political and practical reasons, nurture often gets extra credit. In reality, nurture is what we can control more easily than nature, so we tend to focus on it more. We also recognized that there were dangers in such a formulation we knew how politically loaded discussions of inborn differences could become; we knew that the. Russians had abandoned their experiment in rearing identical twins when it was found that, even reared under different circumstances, they displayed astonishing likeness.  it seemed clear to us that the further study of inborn differences would have to wait for less troubled times. Dr. sigmund freud: may 6 1856 september 23 1939. Freud"s contributions: the importance of the unconscious, the importance of childhood in determining later development. Trust mistrust (0-1: during this stage, the infant learns whether or not they can rely on another human being(s), typically the mother.