4 myths about being a middle child that you should stop believing - according to a psychology professor

In general, middle children tend to be have a more positive view of their friends and friendship in general, and place more importance on those relationships than their siblings, according to a 2003 study published in Human Nature.

While having a super-social and outgoing older sibling can make it harder for a middle child to stand out, there are many other factors that will determine how social a child is, Salmon said.

"About 50% of most of our personality is influenced by genetic contributions, environment, and interaction between the two … as well as factors outside the home, like peers, local culture, and neighborhoods," she said.

Many people think of middleborns as somewhat neglected in comparison to their siblings.

"People can't imagine that that wouldn't mess you up. Like if you're not the sole focus of your parents' attention, then you must suffer in some way," Salmon said.

Salmon suggested imagining what it was like for earlier generations who had large numbers of children.

"They couldn't focus all of their attention on one child," Salmon said. "I think there's this idea that people are easily damaged by somehow not being the center of the universe. I don't think there’s any real good evidence to that."

As several experts told Prevention, there's little evidence that "middle-child syndrome" is real.

In reality, whether or not you fit the middle-child mold is a question of nature versus nurture — but it's mainly a question of how you choose to interact with the world. Your birth order can influence this, but you have the ultimate say as to how to respond to external forces.

"In school, some people may be naturally good at math. That doesn't mean that other people can't figure out how to do it, it just takes more effort," Salmon said. "So for middle children, some things may be easier, but you aren't necessarily slotted into that role for the rest of your life."

August 12 is National Middle Child Day. If you have a middle child, or you are one, it's a good time to make it clear that the Jan Bradys of the world aren't stuck with the narrow characterization perpetuated by pop culture.