Firstborn items on the PBOI tap feelings of being powerful, important, leading, and achieving (“It was important for me to do things right”).
The middle-child items focus on competition, having fewer resources, and feeling unimportant (“It seemed like I was less important than other members of my family”).
For the youngest child items, individuals rate themselves on being the boss of the family and getting others to do things for them (“I was pampered by my family members”).
Perhaps you’ve come to believe the myths both within your family and in psychology as a whole that your character, values, achievement strivings, and life success are determined by the family position that fate, and your parents, awarded to you.
Psychology goes through periods of alternatively accepting and rejecting these myths.