Birth Order 101: What Can We Learn About Ourselves From Our Sibling Placement?

We’ve all heard it said that the order in which siblings were born can go a long way toward explaining their peronality traits. But where did the the birth-order theory actually come from, and is there any truth to it? With TikToks examining the concept regularly going viral, there couldn’t be a better time to dig in, and to find out just what your spot in the family line-up is supposed to mean. Read on for more on birth-order theory.

Where did birth-order theory come from?

The beginnings of birth-order theory can be traced back to the early 20th century, when Austrian psychologist Alfred Adler—who was, himself, heavily influenced by Freud—introduced the concept of the “family constellation,” writing of the specific personalities, strengths, and weaknesses that emerge in children from the same family. “Of course there is much which is the same for all in the same home,” Adler wrote, “but the psychic situation of each child is individual and differs from that of others, because of the order of their succession.”

What’s the birth-order theory conception of an “oldest child”?

According to Adler, firstborn children are likely to be neurotic (as a function of having to learn to share their parents once another child was born), dutiful, perfectionistic, and relatively conventional or conservative compared to their siblings. A 2015 study by psychologist Rodica Damian found that firstborn children tend to “enjoy a small IQ advantage over their younger siblings,” which might be some small consolation for having to deal with eldest-daughter syndrome.

What about a middle child?

Adler noted that middle children may have lower self-esteem than their older or younger siblings due to receiving less emotional or financial support from their parents—but, by that same token, they are more likely to achieve emotional stability and form strong bonds outside of the family unit. Adler also suggested that middle children “may have trouble finding a place or become a fighter of injustice” as a result of their placement in between older and younger siblings. (Fun celebrity fact: Bella Hadid is a middle child!)

And a youngest child?

Adler considered youngest children to be most likely to develop rebellious, outgoing, or extroverted personality traits in order to “catch up,” or, in some cases, differentiate themselves from older siblings. Adler also noted that in adulthood, youngest children might be more likely to “want to be bigger than the others,” or “have huge plans that never work out.” (Amy March burning her older sister Jo’s manuscript in Little Women? That was classic youngest-child behavior, according to a strict reading of birth-order theory, but then again, so was chicly running off to Europe to paint—so there are negative and positive traits associated with that particular birth placement.)

Why is birth-order theory suddenly everywhere?

You can thank TikTok for this one: the phrase “birth order dating theory” has found purchase among users trying to understand the role that birth order can play in romantic relationships. (The hashtag #birthorder is also a popular search term on the platform, having accrued over 500 million views.) However speculative, certain conclusions have proven fascinating: Just consider the example of relationship coach @iammichailatyson, an eldest daughter who realized that she had only been in relationships with men who had older sisters. “[It makes] so much sense that I have gravitated towards men like that—typically men that are looking for mothers, and the role I stepped into was mothering those men,” she said in a video posted in March. Elsewhere, users like @t0nit0ne have broken down the compatibility of different birth-order pairings. (Hint: It’s better to be a firstborn involved with a lastborn than a firstborn with another firstborn. You’ve been warned!)