Here's Why Only Children Are More Successful

First-born children perform better in school, have higher IQs, and are more likely seen as high-achieving by their parents, according to a recent study. As the theories go, earlier-born children may be more successful because they get better genes, more parental attention, and more careful parenting.

As someone who has no siblings myself, I couldn't help but wonder: Are "only" children, who are by definition first-born and receive all parental attention, the highest achievers?

Taken to the extreme, Leonardo da Vinci, Thomas Edison, Condoleezza Rice, and Tiger Woods are just some examples of highly successful people who had no siblings.

While family size in the U.S. has been shrinking since the 1960s and one-child households have doubled in number over the past two decades, there is surprisingly little research on the makeup or potential of only children.

One leading birth-order researcher, Frank J. Sulloway, a psychology professor at the University of California, Berkeley, takes a Darwinian approach to family dynamics. He believes family roles based on birth order and competition between siblings affects behavior and eventually shapes personality. As family leaders, first-borns tend to be more conscientious, he says, while later-borns are more agreeable and extroverted.

Of course, only children, who experience no sibling rivalry, aren't driven to conform to any family role and may be freer to develop their natural aptitudes. "With regard to intellectual ability and success, only children are much like first-borns, since they receive the undivided attention of parents and grow up in a richer intellectual environment - not degraded by the addition of other children in the family," says Sulloway in an email.

As the sole focus of parental attention and approval, only children are usually raised to feel positively special, says psychologist Carl E. Pickhardt, author of "The Future of Your Only Child." They are typically supported and encouraged by parents to develop themselves, and often want to achieve highly for their own sake and also to live up to their parents' high investment and expectations. What's more, without siblings, they are more used to the presence of adults, which may sharpen social and verbal skills at an earlier age.

"Growing up as an 'only' can be very empowering, creating very self-dedicated, strong-willed individuals who push themselves hard to achieve what they want," says Pickhardt in an email.

Indeed, researcher Toni Falbo at the University of Texas has found that only children tend to have high self-esteem and typically perform better in school and get more post-secondary education than other kids.

While only children may turn out to be success-seeking perfectionists, they certainly aren't perfect, says Pickhardt. As adults, only children can be too focused on themselves, often assuming they are right and know best, he says. They can also feel entitled to have more than equal standing and importance in relationships, and may be controlling.

However, the idea that they are brats who don't play well with others has been widely debunked. "Contrary to psychological folklore, only children do not appear to be less sociable or more neurotic than other children," writes Sulloway.