The Surprising Ways Your Birth Order Impacts Your Personality Type

Clinically Reviewed by Steven Melendy, PsyD. on February 12, 2019

Only children can't share. First-borns are bossy. And the youngest child gets away with murder. We all know the stereotypes connecting personality with birth order, and no matter where you sit in your family tree, you likely have some assumptions about how your position in your family helped to shape your personality. 

But is it true that your birth position can drive your personality and behavior? We wanted to find out. So, we asked visitors taking our TypeFinder Personality Test (based on Myers and Briggs' typology) to share their family history. Some 5,747 people generously responded, and we correlated those responses with volunteers' personality types to see what trends, if any, we could uncover.

What do you think we found? Are first-borns really our natural leaders? Are sandwich kids as harmony-oriented and fairness-loving as we think they are? Do the babies of the family enjoy more independence than their older siblings—and the confidence that goes along with it?

I won’t leave you in suspense—the stereotypes are, by and large, absolutely true. When we analyzed the data for all 16 personality types in Myers and Briggs' system, we found some startlingly familiar trends in the four preferences and birth order.

Here’s what we discovered:

First Borns Take the Lead

If you’re looking for a natural leader, look no further than your firstborn. Being the oldest translates into certain family responsibilities that require leadership skills from an early age. Parents tend to invest much more time in their first borns, and expect them to serve as role models to their younger siblings. As a result, parents describe their first-born children as:

  • Responsible
  • Conscientious
  • Diligent
  • Structured
  • Achievers, in terms of educational and career achievement.

Looking at this list of traits, we can predict that oldest children will favor fact-oriented personality traits, namely Thinking (in Myers and Briggs' theory, this indicates a person who makes decisions based on logic) and Judging (the desire to be organized and have decisions made). TJs like rules and guidelines, are conscientious, and respect and trust authority, which explains why they’re overrepresented in the leadership and management ranks of corporate America.

Does the data support these assumptions? Yes—and the results are striking. When we looked at our respondents’ personality results, first-borns, by a fair margin, were Thinker-Judgers. Roughly 19.5 percent more ESTJs were first-borns than we would expect to see if birth order and personality were completely uncorrelated; for INTJs, the figure is 17.5 percent.

Bringing up the rear are the ESTPs, ESFPs and ISFPs with far fewer of these personalities being a firstborn child than we would expect to see if personality traits were distributed by chance. It’s not easy being a free-wheeling Perceiver when your parents are overwhelming you with so much structure and attention.

Type Prevalence Among First-Born Children (Percentage Compared to Expected)

Middle Kids Make Connections

Middle kids are in a bit of a bind. Unlike firstborns, they never had the parents to themselves, but they didn’t get to enjoy all the fuss and privileges of the youngest child either. They get the short end of the stick in terms of parental attention—and are perceived as being eager to please and impress as a result. Here are some of the stereotypical traits we expect of middle children:

  • Easy going
  • People-pleasers
  • Thrive on friendships
  • Gold-star negotiating skills
  • Peacemakers

The prediction here is that middles would exhibit high Feeling preferences, making decisions based on compassion and what is important to people. You might also expect them to lean towards Perceiving (over Judging) since there’s an advantage to being easy-going and flexible as you navigate the middle ground.

So what does the data show? You guessed it—there’s a strong likelihood that a middle child will be a Feeler. Way out in front, ISFP types are a whole 41.67 percent more likely to be a middle child than chance would suggest, with ESFP and ISFJ following close behind. We do note the relatively small sample size for ISFPs, which means these results are more prone to error. But, even if the trend is less exaggerated than these data show, it certainly signals an area ripe for further exploration.

For middles, there’s a negative correlation with Thinking types across the board. In terms of the individual traits, middle kids are 6.93 percent more likely to be Feelers, and 7.23 percent less likely to be Thinkers than if personality had no relationship with your position in the family hierarchy. This is significant!

There’s another trait to consider here and that’s Extraversion. All that floundering in the middle often leads sandwich children to develop many and varied friendships, since parental attention is normally devoted to the firstborn or the baby of the family. Introverts typically find it less appealing to maintain a large network of friends, so it’s no surprise to learn that middles are more likely to be Extraverts than Introverts.

Or, to put it another way, locating an INTJ who is also a middle would be an extremely rare find. Which explains why INTJs are a full 30 percent less likely to be middle kids than if personality happened by chance!

Type Prevalence Among MIddle Children (Percentage Compared to Expected)

Youngests Just Want to Have Fun

Although the youngest gets the “baby bonus” of parental coddling, it’s not all easy for these kids. Parents tend to be less impressed by their accomplishments because they’ve “been there, done that” with older children. And there’s just no time left to police these kids, so they get to play fast and loose with the household rules. This means that youngest children are more willing to take risks than older kids, and they often develop “out there” ways to attract attention, such as being the family clown.

Other stereotypical youngest-child traits include:

  • Uncomplicated
  • Outgoing
  • Attention-hungry
  • Rebellious
  • Self centered

What’s the personality prediction here? We reckon that last-borns would be Extraverted and Perceiving for sure, and may exhibit a slight leaning towards Sensing (living in the moment) over Intuition (future focused), although the latter is a tougher call.

Once again, the data shows this prediction to be true. ESFPs and ESTPs are 22.22 percent and 14.29 percent respectively more likely to be younger children than if personality had no connection with birth order. The opposite is true for NTJs, who are significantly underrepresented in the baby-of-the-family group.

Overall, though, being the youngest child seemed to have the least impact on individual personality traits.

Type Prevalence Among Youngest Children (Percentage Compared to Expected)

What About Onlies?

Only children occupy a special place. They enjoy the full attention of their parents for their entire lives, and do not have to share resources such as their parents' time or money with anyone. Not only do they get more attention than siblings, they typically have adults rather than peers to latch onto and learn from. Essentially, this makes the only child something like a "super-firstborn" but with a bit more freewheeling self-confidence thrown in—these kids can take more risks than firstborns as they have exclusive access to the parental safety net.

In terms of specific traits, onlies are expected to be:

  • Confident
  • Perfectionist
  • Independent
  • Outside the box thinkers
  • Wise beyond their years

The prediction, then, is for onlies to be Thinkers like firstborns, but with less propensity for Judging. In fact, we might speculate a preference for Perceiving. Without siblings to boss around, onlies can afford to be a bit less structured than firstborns.

There are a few interesting trends to take note of here.

First, our ESTP respondents were 100 percent more likely to be only children than if personality and birth order were completely uncorrelated. This is an extraordinary result, and possibly one that should be taken with a grain of salt since ESTPs— and SPs generally—were woefully underrepresented in our respondent group. (The data potentially tells us more about an SP’s attitude to surveys than it does about their birth order personality, so we’re not reading too much into this finding.)

But there are some other trends which are really pronounced—for instance, there are 32 percent more INTP only children than we would expect to see by chance. On the flip side, ESFPs and INFJs are significantly less likely to have grown up as only children, by 44 percent and 34 percent respectively.

Type Prevalence Among Only Children (Percentage Compared to Expected)

Across the board, it seems that being an only child has the most impact on individual personality traits of any family position. Onlies are much more likely to be Thinkers (rather than Feelers), perhaps because they're not under as much pressure to be agreeable with no siblings about. They're also more likely to be Perceivers (rather than Judgers), and slightly more likely to be Intuitives (rather than Sensors), although the reasons for this difference are harder to guess at. It could be that only children get more time to daydream, wonder, and explore in their smaller, less busy families—or it could be that the complexity of parenting an NTP kid leads parents to decide that one is enough!

As to Introversion/ Extraversion, you might theorize that only children would be more introverted since they’re lacking sibling company. Or, maybe they'd be more extraverted, since they have to make more effort to socialize. In fact, the data shows a very slight Extraversion bias—but the data here is underwhelming. Being an only child doesn’t appear to have a significant impact on Introversion versus Extraversion at all.

The Meaning of Birth Order

We did this analysis to see if there were any trends in birth order in relationship to personality type. We were curious to know whether there were certain types that were more likely to occur in a particular birth position, or if particular preferences were influenced by the family structure. What’s fascinating is that overall, the data suggests that what we assume about birth order and personality is mostly true—whether you're firstborn, middle child, last-born, or only child, birth order can have a big effect on your personality in all the ways that parents have observed.

One discovery that we found especially interesting is that some types are much more (or much less) likely to occur in a particular birth position. INTJs, for instance, are unlikely to be middle children. ESTJs are likely to be firstborns. INTPs are often only children and ESFPs are almost never only children.

So, perhaps these findings can help you to better understand what makes you (and your siblings!) who you are. In the meantime, psychologists continue to chip away at an understanding of how our personalities are formed. Birth order may only be a small part of what makes us who we are, but it seems to be a significant one.

Which leaves us with a final question: how do you think your birth order influenced your personality type?

Molly Owens

Molly Owens is the founder and CEO of Truity. She is a graduate of UC Berkeley and holds a master's degree in counseling psychology. She began working with personality assessments in 2006, and in 2012 founded Truity with the goal of making robust, scientifically validated assessments more accessible and user-friendly.

Molly is an ENTP and lives in the San Francisco Bay Area, where she enjoys elaborate cooking projects, murder mysteries, and exploring with her husband and son.

More from this author...
About the Clinical Reviewer

Steven Melendy, PsyD., is a Clinical Psychologist who received his doctorate from The Wright Institute in Berkeley, California. He specializes in using evidence-based approaches in his work with individuals and groups. Steve has worked with diverse populations and in variety of a settings, from community clinics to SF General Hospital. He believes strongly in the importance of self-care, good friendships, and humor whenever possible.


Chad H (not verified) says...

I am a middle INTJ. My elder brother is my senior by 4 years, so I wonder if age spread has impact as well?

Natalie (not verified) says...

I was wondering the same thing. Between my sister and I there’s a 15 year gap. We always clashed growing up so I wondered if it was because we were like two firstborns. 

DavidtheConfident1 (not verified) says...

I read in a study that after an 8 year gap between children, the birth order restarts. So your theory makes sense.

Annie Lee-Hassett (not verified) says...

I was wondering the same as the original commenter in this chain... I'm five years older than my brother, and I'm an INTP. Do you still have access to the study you read? I'd love to read it.

DavidtheConfident1 (not verified) says...

I couldn’t find the original study but a lot of studies now say that at least a 5 year gap is the “birth order reset button”.

Adrianna C. (not verified) says...


I would wonder the same!  I'm an INFP baby of the family.  My sister was 17 when I was born, and my three brothers were 13, 11, and 9, so by the time I was old enough to keep up with them, they were well into their teen years and not around very much.  It would be interesting to have a study done on the effect of birth order and greater age spans between siblings on personality.   

Eta (not verified) says...

I am a middle child too. Both of me and my older sister are INTJs, but we have seven years between us.

Jane K (not verified) says...

I think a wider age spread, different genders, the number of siblings, economics & parental attention definitely makes a difference. Kids with a larger spread can each feel more like onlies

Marsha Escandon (not verified) says...

I have read a fair amount on birth order, but so far none of it ever addresses twins - identical or fraternal.  I am the mother of identical twins and the grandmother of fraternal twins.  I would be be very curious to know how they are affected by birth order!  Thanks!

Molly Owens says...

I'm not aware of any research on that specifically, although there is a lot of interesting twin research in the field of personality. In fact, researching identical twins raised apart is one of the ways they discovered the extent to which genes influence our personalities (it's a lot!). You're right, that would be an interesting topic to tackle!

Anna Stern (not verified) says...

I'm an INTJ 2nd/last child and my firstborn brother is ENTJ (2 years apart). We both developed firstborn traits since we operated as a pair of latchkey kids raising ourselves and he also took on the parental role for me in the earlier years. There was no solid parental authority and I think that made us more self-sufficient than most children. I also have traits of an only child possibly because my brother left home early and joined the military or just typical INTJ traits. 

Christy A (not verified) says...

Anna, for sure, I feel like every family dynamic growing up can affect the results.

Kelly Mierkowski (not verified) says...

I am an Only/ISTJ, and see quite a bit of the characteristics/traits that are stated above in myself, particularly the older I get.

Patricia Fox (not verified) says...

I am the third child, first a boy, mama's boy, second a girl, dady's little girl, then me, a girl,  left to get on with life and get attention and what I needed if there was time and energy left over.  I did pretty good for myself, but not at all like the last child in this article. 

Christy A (not verified) says...

Oldest child INTP here! I am not a responsible, structured, achiever or any of the firstborn traits. But that "extra attention" they say first kids get isn't always beneficial when you fight with your parents or that attention isn't always a positive thing. I'm an independent introvert, and some of those traits may be because of my relationship with my parents. 

Molly Owens says...

Definitely—every family is different, and sometimes the dynamics can be the opposite of what we'd expect. Thanks for sharing!

Kathryneo (not verified) says...

I am the first born of three daughters. I am an ENFJ, as is my youngest sister. My middle sister is an INTP. Our parents were ENTJ - father, a dynamic scientist, and INFJ, our mother, a quiet artist and nurse. My children are son: an INFP, like my spouse; our daughter is an ENFJ, as I am. My stepmother was an ENTJ. My spouse's father was an ENTJ, as is my spouse's brother.

Lori Raderschadt-Guyton (not verified) says...

ENTJ - first born


Lessin says...

I am an ESFJ. I am a first born, who became a middle child through stepkids. So maybe I became an SJ from being the oldest and then EF by being middle.

Elodie (not verified) says...

This research doesn't apply 100% to my family. I'm the eldest but I'm an INFP. However, I am more responsible, diligent and structured compared to my siblings and it did take awhile for me to find my laidback perceiving side which happened when I lived away from my family. I'm not sure if it's my birth order or my mother's J influence. My middle brother is an introvert, I think he is an INTJ or ISTJ, he's totally not like the findings in this post. 

LeAnn Suzann (not verified) says...

Five children in my family, four girls and one boy caught in the middle. I was born second and had great difficulty with my older sister all my life.  Left my home state at 19 and had a completely different, higher powered career life from my female siblings.  Was tested as an ENTJ early on and told that was a good thing in business but I couldn't relate to the description so ignored it.  Decades later in my 60's I took the test again and determined an almost equal split between INFJ/INFP.  Was astounded as this is who I've always been, I had just stepped up to tasks in my career and had adapted traits as needed.  Growing up as a tomboy/cowgirl really helped my inventive/adaptive skills.  My older sister has passed on and while she had some of the traits mentioned in the eldest, she was a marriage prisoner so to speak and struggled greatly with a very confused life.  The effect our relationships have on traits especially for women can be very disastrous, causing us to retreat and change our behavior just to protect ourselves.  All in all, I'm the only really happy (single) one and glad to have found my true identity after all.  Moving on to teaching and being the creative person I've been since birth.

Molly Owens says...

Glad you found your niche, LeAnn! Thanks for reading.

TiffanyJ (not verified) says...

LeAnn - I have also read that as we age we [tend to] move from the exteme ends of each letter to a more moderate center as we learn to adapt to social situations and our environments. Of course, life experiences play a big role in that as well! 

I'm FiNe (not verified) says...

I'm not sure if your research has taken into account other factors of "birth order".  My best-fit type is INFP.  I was the eldest child growing up in my family, and I had one sibling 3 years my younger.  Both of us were adopted as infants.

I don't know my sibling's backstory regarding her biological birth order, but from the story I was told regarding why I was put up for adoption (biological family didn't want to have any more children), I would surmise that I was the last-born of my birth family.  I do resonate with some of what was said about eldest children (responsible, consientious, & diligent), but I also resonate with a couple from middle children (people pleaser & peacemaker) and onlies (perfectionistic, independent, outside-the-box thinker, & wise beyond their years).  I don't resonate at all with the youngest child characteristics.  Perhaps this emphasis of my parents influencing me as described in the article is a reason that I tend to test weakly in preference along the J/P dichotomy (and usually result in a slight preference for J over P on the raw scores).

Aside from being adopted there are people who grow up as foster children and others who are wards of the state or grow up in orphanages.  There are also children of blended families that mix up the order from original family order to blended family order.

My wife (ESFJ) was the youngest of 3 children.  Her eldest sibling had severe cognitive and physical impairments due to birth complications.  Growing up my wife helped take care of her eldest sibling.  [Her family history in large part inspired her to go into teaching special education.]  I would say that she has more of the eldest child characteristics than the youngest child characteristics.

My wife and I have 2 children with the elder (ESFP) being 6 years older than the younger (INFP).  I think that both have more characteristics listed under the youngest child than any of the other groupings.  The elder child did have a time when she demonstated more of the elder child characteristics, but that isn't something that has carried over into her adult life.

Molly Owens says...

Thanks for your comment! Generally studies on birth order, including ours, would be referencing the birth order in the home where you were raised, so in this case, your adoptive home. I can't think of any reason your biological birth order in itself would have an effect on your personality, although anything is possible!

It makes sense that your wife would have more eldest child characteristics, given that she played the role of caretaker.

Your story just goes to show how much individual variation there is in family structures! Even trying to determine whether you're the eldest, youngest, etc. can oftentimes be more complicated than it appears. 

I'm FiNe (not verified) says...

" I can't think of any reason your biological birth order in itself would have an effect on your personality, although anything is possible! "

MBTI theory, from what I have read, suggests that one's best-fit type is something one is born with that does not change over time (i.e., changing one's best-fit type from one of the 16 to another).  To that end it seems that dismissing biological birth-order in a study trying to gauge if there is correclation between birth order and cognitive-preference personality leaves questions unanswered regarding validity.  Also if one could show statistical correlation between order in family of upbringing and MBTI type but no correlation between order of birth biologically, then there would be a challenge to the belief that MBTI type is more nature vs. nurture, biological vs. social.

Regarding my ESFJ wife, one could also claim that it makes sense that she has characteristics associated with the eldest child because those characteristics are descriptive of being an SJ type.


Molly Owens says...

I didn't mean to suggest that there's no biological basis of personality type. In fact, much research has been done on this subject and the scientific consensus is that personality traits are about 50% genetically determined. 

I took your question to be about the birth order in your biological family. Prevalent theories of birth order suppose that differences in personality might arise from the family environment that puts more responsibility on the first born, gives more freedom to the youngest, etc. Since an adopted person does not experience those environmental influences based on their biological birth order, I don't imagine that it would matter whether they were the first child of their biological mother or the last. Of course, they would still have the (profound) genetic influences from the biological parents, but this would be irrespective of their birth order in their biological family.

Liz W. (not verified) says...

What are your thoughts on me being the youngest with one older brother, and I'm an INFP?  Thanks for the fun article!

Molly Owens says...

Glad you enjoyed it, Liz! We found that INFPs are slightly more likely to be youngest children, so you're in good company.

CJ Carey says...

I see articles on birth order all the time but it seems like they only address small families. I'm the 8th of 9 children so I'm not sure where I fit in. I'm not in the middle but not the youngest either.

KJK (not verified) says...

First born ISTJ but only a leader when there is a power vacancy.  Would rather go solo than be a leader.

Jennifer (not verified) says...

I'm an only and an intj! My parents were very neglectful and gave me little attention. when they did, it was more along the lines of it being abusive. 

Greg Wochlik (not verified) says...

I'm an INTJ first born. My brother is 18 months younger than me. There are just the two of us. As I see it, we are polar opposites. I remember back in Communist Poland, aged 6 or 8, when we got our pocket money. Dad took us to buy ice-cream. I would by the cheapest soft-serve available. My brother would blow his whole allowance on a single, delux model. Even though I share a house with him (that is a whole other story), we still don't get along. I can't really pin-point his personality; he is definetly an Exxx.

Tom McShane (not verified) says...

Being a first-born of 7 and a definite INTJ, this survey confirms some long standing beliefs that I have held regarding my childhood.  Regarding the middle children, I would also suggest that you consider the effects of gender -differences in birth order sequence ( ie. first boy/first girl) as there was (in my family) a constant, convoluted battle between myself and my first (of 5) sisters to hold the sibling 'leader' position.  I look back at it with humor now, but it was a constant annoyance to me as we grew up that my sister, K. would repeatedly bring up the point that she was the "eldest girl" and therefore entitled to any and all responsibilities/credits/ recognitions that I was given as the eldest boy, her elder by one year.  It also didn't help (from my perspective) that the birth order of myself and my siblings was M,F,F,F,M,F,F.


TiffanyJ (not verified) says...

Spot on for me (first as an INTJ) and the second sibling (as an ISFJ) in my family, but not the third and fourth of my siblings (we're all born 2 years apart). However, our genders are F-F-M-F and I've read that a switch in gender can trigger a shuffling of the birth order from that child down. My brother (ENFP) acts more like a Middle-Youngest and my youngest sister (ISFJ) acts more like an Oldest again. Can you tell we are the products of two first-born parents with a strong J instinct - LOL! My husband is the elder of two siblings and is a strong ISFJ. 

Jane K (not verified) says...

I agree that parental birth order approaches also affect kids. I'm an only of a second born widowed father & my ex is the youngest of fove. I'm attentive, responsible & vigilant, & he does little parenting & is sorrowful that his parents are gone & no one babies him 

Bobby Masiak (not verified) says...

INTP- Youngest child of two.  However, my sister, was much older than I....married when I was only 10 yrs old.  In mind, a different generation almost...and I barely related to her as a sibling.  She was pregnant when she graduated High School and married two months later.  This created a great rift in our family.  She became persona non grata. NOW I was an only child...for sure.   Over time my parents and my sister slowly reconciled  but by then I essentially grew up FEELING like an only child and this was true even when she still lived at home due to our age difference.  I'm Introverted, an Intuitive (I actually practice focusing on my intuition) a thinker, and perceiver.   Although rooted and grounded as an introvert, I have learned to switch that on and off. Literally like a light switch.   I can, at will, become 'extraverted' in social or work situations, but as soon as I feel it is no longer needed, I become introverted again, without  the need to flip a switch.  In a chamelion like way I just change colors back to my default.  I would NEVER in a million years even WANT to switch Intuition, Thinking or Perceiving .  I love and treasure those.

Guest (not verified) says...

I am INFJ   middle range. Siblings before and after myself are 3 yrs before and 3 years after. I dont believe that matters personally. I spent part of my life with only one sibling living with me, some years with no siblings, some with parent some of my life with grandmother. I always felt like I was not like the others and I treasured my individuality. I also was the only one with blonde hair and very thin. I was the only outdoor child. I recall memories as far back as before age ONE. None of my other 5 siblings do. I was involved in early childhood trauma witnessing a shooting and being covered in blood at 9 months old. Hit by a motorcycle doing 50mph and nearly killed getting off the Kindergaten bus one day. I recall sitting alone in a dark apartment from age 1 to 2 1/2.I watched out the window waiting for someone to come home everyday. I remember thinking I didnt want to be noticed in crowds. I remember thinking cruel looked like monsters and I would never be that or look like that. When I was hurt I recall thinking I never want to be responsible for causing pain like I felt to another. However most children seem to ingest those hurts as a guide to aquiring control and power and a means to invoking fear and intimidation while completely oblivious to what that actually feels like to be the one experiencing such things. I believe empathy is not necessarily a shared human trait I think most people grow up just wanting to find they “belong” with their family and are the same. They should do research on personality types and early childhood traumas and the phenomenon of peer pressure, fitting in, and value of individuality. I believe there is more to this than most realize!

Jane K (not verified) says...

I agree that few siblings have the same parental or familial experiences, & although birth order may affect how we deal with stress & trauma, syress & drama definitely affects our development

Jenice Lumo (not verified) says...

I wonder if personalities have more to do with how the child deals with stress rather than birth order. I know my 18month older and first born sister is wonderfully diplomatic and one of those rare INFJs. I am an ENTP. I was the youngest till my brother came 10 years later. Due to circumstances I really ended up taking care of him for the most part and for the first seven years of his life. 

I was the responsible one. But still not nor ever was a S or J. 

Sonya (not verified) says...

I'm the oldest of 5 and when I first did Myers Briggs 15 yrs ago, I was an ISTJ. When I retested a couple of years ago  I was an INFJ. Even more interesting, I have one child and he is also an INFJ. One of his professors is totally fascinated by this. 

Dawn K (not verified) says...

I am a INFP, first born. With an ESFP brother who is 2 1/2 years younger.  Needless to say we don't get along well. We are just complete opposites. 

Cella (not verified) says...

I'm the oldest (INFP) and have younger brother by about 3 years (ENFP). We have ISTJ/INTJ parents so I think there was a lot of confusion and consternation when we were growing up on my parents part regarding our strong P nature, that is part of what would convince me more towards the biological nature of personality. My parents put lots of pressure on us to be more J, but we just couldn't. Despite this, I have made lifestyle choices more in line with a first born, overall have had a fairly responsible & conventional lifestyle that probably comes in part from being a first child and having such highly responsible types for parents. My brother was able to break the mold a bit more, like living out of a van a rock climb after college, which could have to do with being younger and well, being an adventuresome ENFP! Anways, what I believe intuitively (see, can't stop being INFP) is that we are born with our type preferences, but our families can influence us to such an extent that we can mistake our innate preferences, or even mistype ourselves (who hasn't met someone who just seemed completely extroverted who thought of themselves an introvert, etc). Perhaps as nuerological studies advance there will be more biologically based ways to test the preferences, like being able to compare stimulation on the brains of introverts and extroverts which I believe is already being done. Fascinating stuff to ponder, thanks for sharing this!!

Yochanan (not verified) says...

Thank you for taking the time to write this article.

I wish to enter into this conversation my own experience:

My kids are 13, 11, 9 and 8.  All of them are are well-balanced, leaders, love-fun but work hard when needed, are compassionate, feelers, and are willing to share.  And they're usually obedient.

My wife and I have taught our kids to be mindful and how to demomstrate leadership in life from before they exited their mother's womb. My wife and I have taught our kids 'delayed gratification', justice and mercy (but if one must err in matters of justice and mercy, we've taught our kids it's best to err on the side of mercy).

My wife and I have taught our kids to be independent-thinkers and to make moral choices from an infomred place, and not rush to make decisions. My wife and I have taught our kids to neither rush things or drag their feet, but to do things in their proper moment. And all this we have done through the example we set for them. Are we flawless as parents? No. However, we are striving to teach our children by our example the things we wish we had known earlier in life.

All that said, 3 out of 4 of our kids are INFJ. One is possibly an INFP, but it's too soon to tell for certain. My wife is an INFP and I am an INFJ.

It's very hard to say in our case what role birth-order has played. My 13 years young daughter is very science-oriented and loves to write. She's an INFJ. My 11 years young daughter is very hands-on, loves art (as all my kids do), but she is not as academically-inclined as her sister. She is possibly an INFP--not quite sure just yet. My 9 years young son is an outstanding leader and is very refined. He is an INFJ.  My 8 years young son is skilled with hand-ons things and is very brave and assertive. He , my wife and I feel is likely an INFJ, but it's far too soon to tell with him.

Whatever role birth-order plays among my kids, it's not obvious--except in the case of my eldest. She is the clear leader of the kids.

olivia.beattie05 says...

I’m a last born and I’m a INTP or a INFP (not sure which) and I am rebellious but I’m not a fan of attention.

Shiri (not verified) says...

I am wondering about those people who have multiple families. I am my mothers middle but my fathers oldest. I have three siblings (of the 9 I have) that I never lived with and experienced being the youngest for 6 years until my brother was born. I loved with my mothers kids  for 10 years and my fathers kids for 6 years. So how the hell do I figure out MY birth order? 

Molly Owens says...

It's unfortunate that research like this tends to oversimplify things in order to create neat categories. I think there are probably more families that don't fit neatly into the standard roles than ones that do. My guess is, though, that since you had the experience of being the youngest through your early years, that you probably resemble a youngest child most in terms of birth order effects. 

M e l (not verified) says...

I am a first born INFP. Haha looks like I missed something ?

Sammy (ESTP) says...

I'm a first born ESTP, feeling the same way haha

Dkc (not verified) says...

The youngest child evaluation is SO inacurrate!

P.P. (not verified) says...

I agree. As a last born INFP, I'm am anything but the clown of the family, and yet INFP personality us nearly a perfect fit for me. I'm in my mid-fifties now, and although I do become a clown to relieve stress, I feel that is different than what is being described.

P.P. (not verified) says...

Sorry, that should be an INFJ, not INFP. I'm tired today. 

PsycheAwoken (not verified) says...

I am a 65 year old only child and an INFJ according to my most recent MBTI assessment done with a counselor at a university six years ago.  It is not the only MBTI (ESFJ when my kids were teenagers)  I have been assigned by a reliable practictioner using the full MBTI.  My Mom died when I was 25 and she was reclusive so I often parented myself.  INFJ feels right but apparently makes me a “unicorn.”   Since I am well past the age where I might assume a required role based on need I do believe it is correct.  One aspect of being an only is what I call the “aloneness” that I have always experienced.  Not lonely, simply firm knowledge that I am separate and distinct from others.  I welcome any comments or feedback.  Any other INFJ onlies out there?

Marlise (not verified) says...

I'm an INFJ female last child. So this didn't suite me completely, but I understand there are little INFJs so I can't expect a high percentage. Thanks for the research. It is really interesting.

Scott Paine (not verified) says...

Fascinating study, Molly. I want to thank you for sharing your results. I'm always cautious when teaching personality or using personality assessments to stress that we are talking about probabilities, not certainties. I'm a middle child and an INTJ, for example. That doesn't mean that there aren't patterns toward F preferences, only that I don't exhibit that preference. And we always need to remember that we have more to learn.

FYI this study and your representation of results was exactly what I was looking for to flesh out an illustration of how experience influences our preferences. I'm giving you full credit (of course) and I'm going to start following your blog. Thanks again!  Scott

Molly Owens says...

Glad this was useful, Scott! I hope you have a very productive classroom discussion!

Rita MCB (not verified) says...

I am 3rd of 7.  2 boys, a girl (me), 2 boys, a girl, a boy.  I have first born characteristics being a first born girl.  There is also 5 years difference between the 2nd set of boys so my sister could def. have first born characteristics also.  Then there is 4 years between her and the last born so the last could also have first born charateristics, right?!  My Mom was a saint!!  ❤️ 

dicksen (not verified) says...

OK i am a last born so idc about how much they study us but im nothing like that those fucks dont people understand they will never understand us this life this world thinks it knows everthing about the people thier just words hell im 147 iq and they say any thing they want but im working to break that wall i will not have a lable i will be breaking all thier studuies 

Nena (not verified) says...

I’m an only child and an INFP so can’t relate to your studies. 

Middle one (not verified) says...

Middle girl , born 2 years to day on my brothers birthday and the 4 years later our baby brother came 3 weeks 2 days before our birthday all pieces! I had all the responsibility as the girl growing up and always being told I was the trying one! Now I’m the only one left, my brother was killed in car accident and after that I never received another birthday cake then my baby brother took his life, and now as an adult i have more responsibility with helping my parents and trying to look after my own family. I’ve not gone away without taking everyone or had a mother’s day to my self.. how do I separate that? 

Kate (not verified) says...

I find it quite interesting that as an the eldest child I have the personality and thinking patterns of an INTP. The chart shows 0% for us oldest siblings to be an INTP ?

Stefenie_b (not verified) says...

I am an Infj personality type. I am also an only child. They're wrong on their opinions about one being an Only child  & also being an INFJ. They're completely wrong.

Lena J (not verified) says...

This article was so interesting to me.

I love diving deeper into different personality types.

What is cool is that I wrote a blog on personality types and another on what it's like being the oldest, but I like how this one combines the two.


Deana (not verified) says...

Another thing that can affect the birth order psycology, I believe, is if an oldest child has a younger sibling who has a special need of sorts,  the older child tends to be neglected (not intentionally) and that can make the oldest more independent, protective, and sensitive

Mel F (not verified) says...

I'm sorry, but this is not at all accurate. Growing up in a family of six and knowing a lot of other families, I can clearly see this article is written in a bias. Also, it is very important to take in to account other things than attention and siblings. First, youngest children tend to be very smart, because they pick up on things their siblings know and do not only have flaws. Second, only children may act confidant but also can be very insecure. Between only children, there are also two categories based on how they were raised and regarding their parents. Some only children are very independant only because they have to be and feel they are neglected, while others can be smuthered and overprotected. They also have bad traits too, and it is unfair to leave them out. They aren't perfect. Middle children often are left out and lacking in attention and this can make them very self concious. Oldest children are not all leaders, and it also seems this articles is lacking in one major point--though it is very common for the eldest child to be male, female eldest children act very different. Obviously, gender, race, physical traits, family size, family situation, and wealth all should be playing an important role in this study but are blatently missing. 


Stacie (not verified) says...

I am a middle child but raised an only child since the age of 5 and there is 5 years between me and my half sisters. I can relate to some of the traits of a middle child and some of the traits of an only child. However, it was spot on for the personality type for middle child ISFP.

ENTJ (not verified) says...

What this tells me is that there are a lot of people mistyping due to the effects of their birth order, or just that this study is flawed due to lack of sensors and probably other sampling problems. ;P

And for the record, I'm an only child and have little patience for people who can't share. ;PP

unplanned 3rd born (not verified) says...

The first born was conceived following a "one for the road", last hookup with the biological father. This child was doted upon, cherished, and has always been the favorite. 


The second born, was the only son. Cherished, and doted upon. 


Bring the third born. is a lot like being the bastard stepchild. Even when I was run over by a drunk driver while riding my bicycle (and dragged several feet, while my legs were pinned beneath my bicycle as the car was accerating at the same time), my parents shrugged it off, saying "0h you can still walk, so you're okay". and this is no exaggeration. It is one example, of many. 

In my experience, as the third born, you simply are not valued, cared about, or seen as worthy of receiving parent's time, energy, or emotional engagement, as others in earlier birth order. 

Also, as my parents aged, the siblings in earlier birth order did little-to-nothing, to help the parents with their elder life issues. I was the one in the trenches, helping when Dad went through terminal cancer. And for the subsequent 23 years, I was the only one who helped Mom. My siblings never responded to my requests to get involved & help with Mom, over the years...and their lack response was expressed in a deafening silence. 

As the years passed, Mom became more and more demanding, and her elder life issues became more complex. Eventually it just became too much, and around this time, i realized that the more and more I did for her - the more demanding she became...and no matter how much I did fir her - she would never appreciate or value me, anywhere near the wat she values the earlier-born siblings, despite the fact that they couldn't be bothered to help her with anything in the 20-plus years since Dad passed away. 

So after some thought, and soul-searching, I informed my Mom that I was resigning from being placed into the role of her "surrogate husband", and effective immediately, I would only be her daughter, and that's it. Her reaction was to laugh out loud. to which i responded, that I'm not joking, and it's not funny. I explained that she has other family members that have done little to help her in the past decades, and now it's their turn to get involved, because I'm done. 

In my opinion, and experience, as the third-born, you receive the least  (if any) support from your parents during your formative years, adolescence, and adulthood...and they can't really be bothered to care about you - unless they're either judging, fault-finding, or blaming you for something - or unless they want something from you, and perceive you as a resource for themselves. 

I never hear from my Mom, unless she wants something. And I have stopped trying to nurture relationships with my unresponsive siblings. 

With all due respect, you missed quite a lot in your article. Perhaps a candid glimpse into the experiences of one third-born person might help illuminate things somewhat more clearly.

Sharonlee Goodhand (not verified) says...

Interesting reading. 

Unfortunately it doesn't answer the questions that set on the path researching birth order traits. 

I wanted know more about larger families,  those with four or more children. 

Although in my case, first two children were born 2 years apart... next 2 were born 2 years apart but 8 years after the first two. 

I suppose this means the birth order was reset?

However that doesn't seem right because they all grew up together as one family. I did my best to share my attention equally and encouraged family togetherness.

Christopher585858585858 (not verified) says...

Yep, I do agree with these statistics. What I mean by that is that I find them logical and correspnding to my observations.

I am a fiirst born INTJ

Christopher585858585858 (not verified) says...

Also, my small brother is an ISFP

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