Does Birth Order Affect Your Personality?

There’s all kinds of stereotypes about what your position in your family says about you. Oldest kids are the most responsible, the ones in the middle are rebels and since I’m the youngest, I must be spoiled. And sorry only children, according to society you’re selfish. It’s called birth order theory. And it might sound like an appealing way to explain why your older brother is so overbearing and competitive, or why your younger sister always has to get what she wants. But even though psychologists have used birth order theory to explain personality traits for decades, recent studies are finding that it doesn’t actually seem to matter where you are in your family. The theory dates way back to 1908, the early days of psychology, when it was proposed by Austrian psychologist Alfred Adler, a buddy of famous psychoanalysts Freud and Jung. All three of them agreed that experiences a person had as a kid could have big impacts on their personality as an adult. Adler took it one step further and argue that a child’s position in their family would have a big impact on their development because each kid would experience a different psychological environment. In his writings he theorized that the firstborn child starts out as the spoiled only child and is basically dethroned when the next sibling comes along after getting bumped, the oldest child ends up overbearing and neurotic since they feel responsible for looking after their younger siblings. Middle born children on the other hand, they’re likely to feel overlooked and become the rebels of the family. And the youngest children might be babied by their parents, so according to Adler they typically end up the most spoiled. Adler never used any scientific research to justify his theory but he used it as a therapeutic tool when working with his clients anyway. As the idea became more popular, psychologists realize that they should probably do some actual research to find out if birth order theory was actually true. Personality is a complex thing to try and quantify and it can change over time, but scientists have figured out a way to sort of measure personality using what’s known as the five factor model or just the Big Five. It’s not so much a theory of personality as it is a way to categorize different traits on sliding scales. People can take a test to see where they fall on the scales of five traits; openness to experience, conscientiousness, extraversion, agreeableness, and neuroticism. Based on a handful of early studies, some psychologists are pretty convinced that you can connect birth order to specific big five traits. Like oldest children are more conscientious and neurotic while youngest children are more open to new experiences. And this approach is really appealing because it sounds totally plausible right? Like I have an older brother, he’s pretty neurotic. But those earlier studies have a lot of flaws and the more recent research with bigger better design studies, hasn’t found much of a connection between birth order and Big Five personality traits. One of the problems with those smaller studies was that they often depended on one sibling self-reporting their personalities and those of their siblings, like what I just did. So if the researchers were interviewing an oldest child for example, the subject was more likely to report that they were more responsible, while their free-spirited little brother was more open. But the difference between the way someone sees themselves, and how they see someone else, can really affect the result of the survey. New studies had other flaws too, for instance they mostly looked at the differences between siblings within the same family and they interviewed everybody around the same time, which meant that the people born first were always older than the siblings they were being compared to. So if the researchers found that firstborns tended to be more responsible was that because they were born first or because people just tend to get more responsible as they get older. So even though some of those early studies did seem to find a link between birth order and personality, their flaws meant that the results weren’t super reliable. Now more recently, researchers have been using much bigger data sets to analyze differences in large groups of kids from multiple Western countries. And it turns out that once you start comparing traits across families and looking at more subjects, the effects tend to go away. In two huge studies published in 2015, scientists were able to compare tons of different kids across lots of different families. One of the studies looked at almost 400,000 US high school students, and the other included over 20,000 students from the US, UK, and Germany. The one difference they found, and if you are an older sibling I expect you to hold this over your younger siblings, was a small change in intellect, which is considered one of the sub traits of openness in the big five. Siblings born first tend to have a very slightly higher IQ than siblings born later. We’re talking like a couple of points. It could come from firstborn kids getting a little bit more direct attention from their parents at an early age. But as we talked about before here on Scishow Psych, IQ is just a way to measure learning ability, and that’s only one part of the complex concept of intelligence. And it can be affected by lots of different things like how motivated you are to do well on the test. And other studies looking at things at the data haven’t found an affect of birth order on IQ at all. Other than that, these gigantic studies found no significant effect of birth order on any of the other big five traits. So most psychologists treat birth order theory with a healthy amount of skepticism these days, although it hasn’t been totally disregarded. Birth order might be an appealing way to explain differences in the behavior of siblings, but when you look across large groups of families, the effects just aren’t there. You might know individual people who fit the stereotype of an oldest sibling who’s more responsible, or a youngest who seems spoiled, but there are also plenty of responsible youngest children or oldest children who act like total brats. Over time and across populations those traits balance out. So birth order theory doesn’t actually explain why your middle sister ran off to start a rock band, that’s just because she’s awesome. Thanks for watching this episode of Scishow Psych brought to you by our patrons on patreon. If you want to support us, you can go to, there’s a bunch of cool stuff there, also it’s how we make this stuff. And if you want to learn more about how these weird brains of ours work, you can go to and subscribe.

100 Replies to “Does Birth Order Affect Your Personality?”

  1. As a middle child I couldn’t help but notice that you spent the majority of the video talking about oldest and youngest children, glossing over the middle children. Stereotype confirmed, we’re always forgotten.

  2. I have two siblings and, although I’m a twin I act like the oldest and, if that even counts, I’m the only one out of my siblings who fits a category.

  3. I'm the older sibling but i'm the rebellious free-spirited open one and my stupid sister is trying to act all responsible it's so funny lmfao

  4. Oldests are smarter. My oldest brother is a genius. All my teachers knew it; they'd talk about how he knew everything so they didn't care when he slept in class. One history teacher told our mom he knew more than he did; I do not think he was exaggerating. He's read so many history books. He also owns at strategy games or just any video game. He reads extremely fast, too. He got 5s on his AP calculus and Econ exams. Just so smart.

  5. Birth order definitely has a significant effect on people, otherwise, I wouldn't be able to guess with notable reliably the birth order of people under ~30 from at least 3 very different cultures. The effect does seem to be less obvious with age, so I imagine that the effect is less strong on basic personality and more significant on more fluid preferences and tendencies which, though related to personality are influenced by stage of life and social environment among other things. It is not invalid to test the people at the same time in one family, the meaning of your results is then more connected with the people's relationships to each other which is a valid and interesting sort of thing to investigate.

  6. my lil sis is very spoiled. i try not to ask for anything, in order to be nice. i am definetly more education-focused then her, and i am less sotial and money countious. i did get more of my parents attention when i was young. Birth order traits definatley apply in my family.

  7. i am a only child and i am not usually selfish. but then again my brain is weird so i am usually selfish because i dont know when to stop. But i usually prefer to talk about others.

  8. Youngest offspring, here. From childhood, up until now, it's been a constant factor that when any of my three older sisters try to grab my parents' attention (most notably the trouble-making second-born), then I may as well not exist.
    And because my parents have been through the whole experience 3 times before, many positive things that I do are played down, when compared to the attention that my sisters got/get. For me, being born last ensured my place on the back-burner.

  9. Lol this is false. Im the younger child of 2 BUT the caveat happens to be that my older sister was the first girl on my mom's side of the family. So all the attention I should have garnered by being the baby boy……was giving to the real baby…my older sister. And I have 2 older sister that are not my mother's children but… I'm not close to my dad's side which happens to be overrun with girls. I can't win for losing! 😂😂😂

  10. I'm less than a year older than my brother, and especially as we've gotten older I feel less like an older sibling and more like a peer. Although I do think that, to an extent, the way I view him still is and always will be somewhat colored by the fact that he's my younger brother, and it's probably the same for him. It's like a social marker that at this point has very little material influence on our interactions but still exists in the way our brains categorize each other.

  11. I love your show… tell me, do you have a video about intelligence? There are a lot of people who say that x or y person is intelligent, but I think they understand "intelligence" differently to me. Types of intelligence, iq, what do people mean?

  12. i have 4 older siblings and 9 younger ones. But yeah, I know I'm more responsible now in my teen years because I actually listen to my dad when he gives us lectures on "how to behave in our house" (why do they have to be so gosh darn long!?) And since my older siblings aren't around anymore to babysit, (well they are, but y'know that's life) I have to do it. (YES IQ IS TRUE I KNEW IT I KNEW IT YES YES YES YES YES YES YES YES YESSSSSSSSSSSS)

    i might possibly be more wise than everyone in my house….

  13. Idk, take my situation for example, I am a middle child
    1st born – sister – (family lady) responsible, conservative and family oriented, neurotic, overly emotional, most diligent, average IQ, clean, materialistic
    2nd born – me – (social butterfly) responsible, open minded, independent, calm, not very emotional, lazy, a bit rude, highest IQ, moderately clean, non-materialistic
    3rd born – sister – (indoor gamer) irresponsible, open minded, completely dependent on family, grumpy, very emotional, moderately diligent, average IQ, messy, selfish…..but the prettiest of us three

    I would say that my older and younger sister are both spoiled compared to me. xD Both are used to getting everything new and they both are capricorn. XD One thing they have in common is that they are hypochondriacs, enjoy attention and use it as a form of mild manipulation. Sometimes I envy them because that's how they get everybody to do what they want….but I could never whine about anything because I like to be a person who seems tough and independent….

  14. I am a middle child and always very passionate about this subjects because we're always overlooked – which is also the case in this video.

  15. I have an older brother and a younger sister. My brother has always been a nice guy, never fought with any of us, he could be a bit shy to people, but then he started playing guitar… My sister is also a very nice girl, but she was the most spoiled one and the one who would easily get angry. I was the patient one, kinda quiet and I would always let my siblings take the biggest cookie or the front seat in the car (up until last year I had never sat in the front seat in the car and I'm 16).

  16. I am basically a middle child, I am the second oldest but I have many symptoms of "Middle child syndrome". But that isn't similar to this personality theory, I am responsible (I have gotten to do many thing because of this), I am will most likely be as smart as my sister we when I am her age, and for the most part I am not rebellious, even though my name does mean bitter and rebellious according to the inter webs.

  17. Yeah when it comes to my family, they're fairly on point with that theory. My little sister is a drama queen who likes getting what she wants and my brother is a jerk. Meanwhile I'm the anxious one in the middle who always got bullied and put down from the older brother, and always expected to be a role model to the little sister.

  18. Well, smaller child in a family of two siblings, but I performe much better in IQ tests. Maybe other factors can be taken into consideration. Such as genetic traits how parents themselves fit into birth order.

  19. I think the differences between younger and older siblings might depend on expectations. Older siblings tend to have higher expectations of their younger brothers and sisters than they were exposed to by their parents when they were that same age. That tends to cause frustration and demotivation.

  20. Just Imagine yourselves in either the first, middle or the last role and you will more or less get to understand those different placements affecting and consequentially developing and shaping the unique personalities, traits and strengths of such a person.

    Eldest is about dealing that from being the only child you now have further new siblings to contend and keep an eye on and to being responsible of them being safe within the Family Belief and System. Also to occasionally taking the Authority to Lead as certain urgent circumstances arise.

    Middle is about existing and functioning as being the younger to the eldest and ALSO the elder to the youngest and to somehow making and keeping all these things miracalously work out great, together and well. They also would dislike discordance to stability and peace. Surprisingly they can be very talented and self reliant in getting what they want.

    The Last is about already being within an established family environment and to then be the innovator or the solution maker for the Family progression and/or its Values. They tend to get to be more lively, unique and creative but not to heavily more concerned of others as compared to their elders. They could either be the great last presentor of the Family or a TrailBlazing individualist breaking out or leading out from it.

    Well the only child is probably just as self pampered as are they a self reliant Unique Individual.

  21. I agree that birth order has a strong influence on personality, it’s part of your up bringing, but it’s not just simply the birth order, it’s the number of children, the number of years apart the children are spaced, and even the genders can influence the treatment of birth order. For instance you have two girls and one boy, let’s say that boy is a middle child, he may have many middle child characteristics but because he is their only son, the middle child syndrome may be diminished, or mixed with an only child syndrome, just depends. Lots of factors at play👌

  22. Im a middle child and I observed that my younger brother is sorta narrow minded and stubborn which is quite the opposite of what a younger child is. Sometimes he may tell me to do chores just because he isn't able to do it himself. there are times when I ask him to get off the couch and play basketball outside with me, he refuses to do so. now you might ask me why I cant just spend quality time with him but its not that. its more actually more than that, sometimes he might just joke around or touch me to get my attention. and while im still not fazed by his actions he starts getting more angry at me and when that happens I respond by blowing a mini punch to his face just so he can stop. sounds reasonable since hes the one initiating the contact and theres no one who save his ass except me.

  23. I'm really curious to hear what researchers end up finding about this stuff as epigenetics become better studied.

  24. I think it's more of a group dynamic thing. Groups of people tend to adopt roles to balance the dynamic even if those roles don't generally fit their personality, it could be that families do this too.

  25. I am the oldest sibling. When I was a kid, my parents were fairly young and not too busy, so they had more time to enforce stricter rules, I had regular curfew and daily schedule, and I had better study habit because both parents had enough time to contribute actively. By the time my siblings came, however, my parents are less active because of their old age (the age difference between me and my siblings are pretty far, 8 and 12 years respectively, my youngest sibling's was a risky pregnancy because mother was too old), so my parents tend to be more passive and my siblings don't even have curfew (they go to sleep only when mother scolds them). They ended up a bit spoiled and less self-reliant. A lot of factors resulted in different ways of parenting, thus it also would affect the children's personalities

  26. Naw, being the youngest, I don't feel like I deserve nice things. It's my middle sister who's spoilt and also my middle child. So… middle maybe?

  27. Lol I am actually a middle sister in my family, and if you count playing Rock Band on my PlayStation as "running off to start a rock band" then I've satisfied Hank's fun example at the end of the video 😂

  28. As my sister and I grew up I (the youngest) became the successful/responsible one, while she (the straight A student heavily involved in extra curricular activities) is the one still living at home.

  29. I've got a few questions: Why do some people believe in the zodiac so much? And does it hold any truth at all? And where did it start?

  30. 2:31 🤣

    4:08 Ouch… so true for my older brother. #TurnedDownMENSA

    I see a little more correlation with favor/disfavor. At least that's what I see from my perspective, which – as discussed – is probably lopsided.

  31. Revoir des choses déjà vue pour récupérer une conscience à la con que j'ai depuis le début mais qui vient et part

  32. I’m an oldest child, I honestly fit the middle child thing so much better, and my younger sister acts like the stereotypical oldest child

  33. please do one on cesarian section vs natural births on personality traits. IMHO a huge myth waiting to be debunked on YouTube.

  34. Hi I'm the oldest child but I fit the middle child stereotype and my sister, who is the youngest fits the oldest child stereotype so explain that adler

  35. I'm the middle and SO mature and Responsible just leave me with 10 babies and I will be fine 😂
    I'm the second child and I'm coropative, ( I am NOT flexible or sociable) I am able to make or maintain friends ( ._.) I'm less competitive. I am NOTTT a social butterfly cause I'm depressed and everyone just thinks I dont
    My brothers (I have 2 one the oldest and the other youngest) and oh somebody kill me. Since I am a girl, I am like a punching bag to them. They would suffocate me with pillows, kick, scratch me SOOO close to my pupil and the white part of my eye, punch me, and all violent stuff

  36. It's most likely half nurture and half nature. Same way you can take clones off of one plant and let two different people grow them in different environments with different techniques and you'll be able to spot differences in the exact same genetics.

  37. In my family we were basically Ed, Edd, and Eddy. My older brother was always out trying to make a buck, he used to order those get rich quick books from the TV commercials and he'd always be out mowing lawns during the summer. My younger brother got into hard drugs way too early so he was never all that bright. I've seen him walk into the local grocery store, grab a six pack of beer, and walk out, telling an officer on the way out that it was stolen. He's really that thick. And yeah I found a moldy sandwich of his under my bed once too. That was fun. Meanwhile I'm in the middle, your pretty typical shy nerd. Instead of a hat it's a hoodie tho.

    Never heard of this order, though.

  38. Im oldest and deffff not the most responible… Or best in school. My little bro always lookt after me without asking and his grades are way better then mine! I was the rabble and the bit spoiled ackting one if you ask me.

  39. I am the oldest in my family with one sister… My sister is the adult with 2 children and I am a 12 year old in an adult body!

  40. "…Doesn't explain why your middle sister ran off to start a rock band. That's because she is awesome."
    sounds like you'er projecting a bit.

  41. Many people complain about the middle child being glossed over. And though it is a curse, it can also be a blessing. I get away with so much crap and such that my siblings could never get away with. Nobody notices me and therefore, I can take complete advantage of that and live my life by my rules.

  42. I heard the opposite. i heard that the second born and after get more benefits during pregnancy because there are certain changes that happen to the women's bodys that help a baby get blood, food etc the first time and those are already developed, strong and ready to go for the next kids.

  43. Every IQ-related test and sample Mensa test I've ever seen had those questions that you matched or predicted patterns of geometric shapes. I always thought these stupid with no basis in real life, unlike word relationships and mathematics puzzles. In fact, I think solving jigsaw puzzles is a much better measure of and training in life intelligence than those ambiguous, abstract geometries.

  44. We're all bullheaded, my sisters and I, with my older sister being bossy and parent – like. I was quite easy – going, but I often felt a squeeze in the mornings, getting ready for school amongst grumpy family (except my dad; he's a rock). I was cheerful out of self – defense.

    My little sister was a leader with the ability to tell where people most excelled. But when she got an idea in mind, she wouldn't let go, she would force it to happen.

    Strangely, I think, as a middle child, I was the most open to new ideas. Truly, though, as we grew up, each f us took on traits of the others.

  45. Older/ younger siblings will always be at their own point of development, but despite the age difference they always will be compared. So it is actually pretty obvious that more "adult" traits like keeping order or caring for certain issues in a deeper way will be viewed as neurotic/ consciencous by younger siblings, while the natural clumsyness of a young adult who has just moved out of their parents home will be seen as especially unorganized and negligent.

  46. I read "birth control" first, so naturally I was confused how the fact that you have been aborted would not have an effect on your personality ;D

  47. The oldest in my family is the least responsible person I’ve ever met.
    Me (a middle child) is terrified of breaking rules and neurotic
    Needless to say I’ve never believed this but it’s still really interesting

  48. My oldest sister is bossy but our middle sister is a successful lawyer & I’m the spoiled youngest for sure but my IQ is dramatically higher than my 4 older sisters

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