The Oldest Child
Common traits of firstborn children: responsible, higher achieving in school and work, ambitious, risk averse, feel more pressure from parents, defensive.
Royal oldest children: Queen Elizabeth II, Prince Charles, Prince William, Kate Middleton, and Prince George.
What we can learn from them: In Britain's royal family, the eldest children typically carry the heaviest burden — simply because they are in the direct line of succession. They must prepare for their duty as future monarch practically from the moment of birth, meaning they often present a responsible, tightly managed royal persona to the public.
"Firsts tend to be secure in their roles and are relatively risk averse."
For us commoners, it's also true that firstborns tend to be more responsible, says Salmon. She points to the book Born to Rebel: Birth Order, Family Dynamics, and Creative Lives by Frank Sulloway, which notes that firstborn children identify more strongly with authority figures and conform to longstanding conventions. "Firsts tend to be secure in their roles and are relatively risk averse," Salmon explains.
For the royals, these personality traits become apparent when you compare the Queen, Princes Charles, Prince William, and Kate Middleton to their younger siblings. (Do you recall Pippa Middleton's near brush with jail time in Paris back in 2012?) With the exception of Prince Charles's various scandals during his marriage to Princess Diana, firstborn royals tend not to rock the boat. And they generally take a professional and controlled approach to their duties. In fact, Prince Charles may have married Princess Diana out of a sense of duty, as he barely knew her but needed to find a wife who met the strict standards for a future queen (aka an aristocratic woman who was a virgin). According to a recent biography of Charles, the Prince of Wales wept on the night before his wedding and wrote a confidant that marrying Diana was "the right thing for this country and for my family."
In addition to feeling more pressure and expectation from their parents, firstborns interact more with adults as children. It is adults who act as early role models for the eldest child, whereas laterborns look up to their older siblings. (You can see how expectations may be different if you're taking cues from an adult vs. a toddler.) This was true for Queen Elizabeth, who had a close relationship with her father, King George VI. A 2012 biography of the queen reveals that the king was the young Princess Elizabeth's closest mentor, since he alone could tell her what it was like to be the monarch and how to best meet the challenges that came with the unique job. Similar parental attention may explain why commoner firstborns have better outcomes when it comes to their education and work achievements.
Of course there are always exceptions to the rules. Queen Elizabeth's uncle and fellow firstborn King Edward VIII abdicated the throne in 1936, when he was unable to marry divorcée Wallis Simpson and still be king. Instead, it was his more responsible younger brother Prince Albert, who fulfilled his duty and became George VI.