How Family Position Shapes Personality Birth order is one of Adler’s most widely known and most misunderstood contributions to psychology. The popular version goes like this: first-borns are responsible and achievement-oriented, middle children are peacemakers, last-borns are rebellious and creative, only children are spoiled and self-centered. This is a simplification that borders on astrology. Adler never claimed that birth order determines personality in any mechanical way. What he argued was that your position in the family constellation creates a unique psychological situation that shapes how you interpret your place in the world and how you develop strategies to secure significance...