There are lots of expectations and assumptions about how birth order may shape our adult lives, and many of them go back ages. Centuries ago, the oldest son had huge incentives to stay on track and live up to family expectations -- that's because, by tradition, he was set to inherit almost everything.
"Historically the practice of primogeniture was very common in Europe," says Frank Sulloway, a visiting scholar at the Institute of Personality and Social Research at the University of California, Berkeley. "So firstborns had every reason to preserve the status quo and be on good terms with their parents."
Now you may think any "first born" effect would have completely disappeared in modern times. But not so, say experts who study birth order. Researchers first examined the status of firstborns among Washington power brokers in 1972.
"I expected that there would be a disproportionately high number of firstborns among members of Congress" says psychologist Richard Zweigenhaft of Guilford College. "And that's exactly what I found."
Out of 121 representatives and senators included in his sample, Zweigenhaft found that 51 were firstborns, 39 were middle children, and 31 were youngest children. It wasn't a huge overrepresentation of firstborns, but the difference, he says, is too significant to ignore.
Several surveys and studies conducted throughout the years have found that firstborns do edge out later-borns in lots of high-achieving professions, from corporate CEOs to college professors to U.S. presidents and Supreme Court justices. There's even evidence that firstborn children are about 3 IQ points smarter than their second-born siblings.
So what nudges oldest children to be conscientious, striving achievers? One factor is that firstborns tend to get undivided parental resources, explains Sulloway.
"When the second [child] comes along, the oldest still gets half of all that [attention], so younger siblings never have a chance to catch up," he says.
It's not that mothers and fathers intend to parent differently -- oftentimes it just works out that way. Partly it's the inexperience that makes some first-time parents go overboard: signing children up for every lesson and activity imaginable, for example.
Monica Hanson says this was the strategy she took with her oldest daughter
"Oh, gosh, she did everything," recalls Hanson. "I put her in tennis lessons, dance lessons, art classes, music, swimming." She says her son, who is seven years younger than her daughter, didn't do nearly as many activities.
Hanson says birth order played a role in her own childhood, as well. As the eldest of four siblings, she did get the ballet lessons and a lot of attention early on, but she also sensed that her parents had high expectations. She was expected to do well in school and to help out with her younger siblings. She also recalls that her parents held her to stricter rules, like an earlier curfew.
"I don't think they did it on purpose -- but I was expected to do a lot of things, to be unselfish, to get it done," she says. Hanson says she never pushed back -- she fell into the firstborn role naturally.
To this day, Hanson is still seen by family and friends as the doer -- the boss, the person who can hold everybody together. And she's never outgrown many of the firstborn influences.
"Let's say, for example, if I'm going to run a banquet for my daughter's school," says Hanson. "I'll do the best I can." She's known as a person who will bring 100 percent every time.
Amalgams Of Influence
Experts say it's never entirely predictable how birth order may influence our personalities, behaviors or family dynamics -- there are plenty of firstborns who don't fit the mold.
"The one thing you can say about birth order is that it's not absolutely deterministic of how people's lives turn out," says Sulloway.
Experts say it's just one small piece of the puzzle.
"I'm not sure I would say that birth order plays a strong role in who we become," Zweigenhaft says. "Birth order contributes to who we become."
After all, we're all amalgams of many childhood influences, from teachers and peers to random life events, including turns of good luck and bad.
Hanson says one of the traits she sees in herself and all of her sisters -- a love of life -- can't possibly be the work of birth order. She chalks it up to the spirit and values they learned from their father.
"He said you can do anything you want in this world, but whatever you do, make sure it's what you want," Hanson recalls. "Don't compare yourself to anyone."
Hanson says her father preached that same message to all of his children, from the firstborn to the baby.