Birth Order and Psychology - Siblings Week


Famous siblings the Marx Brothers with their parents {{PD-1923}.}

When the call went out to BreakThru Radio’s writers to select articles we wanted to write for sibling week, I figured I had to take one. After all, I host a thrice weekly radio show on this station with my sister. She and I also host and produce a monthly stand up show at Le Poisson Rouge in Greenwich Village. Not to mention, we have a web series called John and Molly Get Along. By rights, I should know as much about birth order and psychology in siblings as anyone.

However, a little bit of reflection promptly destroyed that confidence. I don’t feel particularly like being the firstborn in the family played a significant or defining role in my personality, but, then again, how would I know what it’s like not to be the firstborn? Just like growing up in Iowa, just like being a white man, just like having parents who are both educators all played a part in determining my personality, so did being the firstborn male with a younger sister. Frankly, it made me the best kid in the family.

There is obviously an incredible amount of research into the effects of birth order on personality, and even more wild speculation around it. Before presenting some of it, a quick caveat is in order. I’m skeptical about any claims of determinism regarding birth order – e.g., firstborns make lists – even when they come from reputable studies.  There is plenty of dissent in the field.

One of the most well-known researchers on birth order is Frank Sulloway, who authored the 1996 study Born to Rebel: Birth Order, Family Dynamics, and Creative Lives. Sulloway’s primary finding – which has since been challenged – is that “the eldest children identify with parents and authority, and support the status quo, whereas younger children rebel against it.” The theory is that younger siblings need to distinguish themselves from their older siblings to gain parents’ attention. Often that distinguishing behavior falls outside the status quo, and before you know it you’ve got a revolutionary.

Not everyone is convinced that birth order is so significant, though. Dalton Conley, author of  The Peking Order, is much more skeptical.  According to him, “birth order makes about as much sense as astrology, which is almost none.”  His book argues that personality and success levels are far too complicated to be reduced to birth order. Susan Bailey, MD, writing for Psychiatric Services, characterizes Conley’s findings this way:

“Differential success among siblings is not, he argues, a simple matter of genetics, gender, or birth order, or of parental intentions or innate talent. Rather, success is a complicated, multifactorial outcome, shaped by economic and social forces impinging on family histories at distinct points in time, predicated as much on luck and accident as on good genes or strong character. Conley’s accounts of differential success among siblings encourage us to look more thoughtfully at our patients and our society.”

Attempting to find patterns in firstborns, youngest children, and middle children among different families, then, is often a case of bringing one’s preconceived biases into play. If you want to find that the youngest are rebellious, you can do that. If, on the other hand, you want to find youngest children who are docile and obedient, you can find that as well.

Further research shows that birth order is far less significant than society at large often assumes. A study conducted by Vassilis Saroglou and Laure Fiasse determined that “Effects of birth order on personality are modest but not inexistent.”

I find Conley’s and Saroglou’s findings far more persuasive than the more deterministic Sulloway’s. The interpersonal and cultural dynamics at play in a family are so massively complex as to render any generalizations between them irrelevant. And the fact that I’m saying that is completely unrelated to me being a firstborn – at least, I think it is.

Written by: John Knefel