Birth Order

Alfred Adler, founder of individual psychology, first introduced the concept of birth order. Adler identified characteristics of different ordinal positions, but he also emphasized the importance of psychological birth order and relationship dynamics within the family system. Adler believed that a family member’s perception of his or her position within the family of origin may or may not match the actual ordinal position. For example, in a family with three siblings in which the oldest becomes chronically ill, the secondborn child may hold [Page 261]typical firstborn traits. This entry first covers the earliest research addressing the influence of birth order on personality development and then describes the characteristics of only children, firstborn children, secondborn children, middle children, and youngest children.