海角大神

Oldest? Youngest? Birth order doesn't influence personality, study says.

Researchers have found that the birth order among siblings doesn't matter when it comes to personality, and only very little when it comes to intelligence. 

Everyone knows the familiar stereotypes: the smart, responsible first-born sibling; the rebellious baby of the family; the easy-going middle child.

But those stereotypes bear little validity, according to a that researchers say is 鈥渢he biggest in history looking at birth order and personality.鈥澛�

A study of 377,000 high school students by University of Illinois psychologists found that firstborns have an IQ advantage, on average, of just one point over their younger siblings.聽

The analysis also showed a pattern of differing personality traits between first-borns and younger siblings 鈥� first-borns were, on average, more extroverted, agreeable, and conscientious 鈥� but those differences were 鈥渋nfinitesimally small" as well, said Professor Brent Roberts, who led the study.

Statistically, the results correlate with the classic聽 developed by psychologist Alfred Adler in the early 20th century: the firstborn as a natural leader; the spoiled, lazier youngest child; and of course the oft-ignored middle child. Adler's theory has been debated among psychologists for years: some, like , maintain that Adler was largely correct. Others, such as , claim the effects of birth order have been significantly exaggerated.聽

In real life applications, Prof. Roberts says, the differences in personality and intelligence are so minor that they're ultimately insignificant.聽

鈥淸I]n terms of personality traits and how you rate them, a 0.02 correlation doesn鈥檛 get you anything of note," Roberts explained in a聽. "You are not going to be able to see it with the naked eye.鈥�

鈥淵ou鈥檙e not going to be able to sit two people down next to each other and see the differences between them,鈥� he continued. 鈥淚t鈥檚 not noticeable by anybody.鈥�

Postdoctoral researcher Rodica Damian, now a psychology professor at the University of Houston, the large sample size was the key to finding accurate results. This study compared children from different families, whereas most other analyses have only compared children within the same families.

鈥淪uch studies often don鈥檛 measure the personality of each child individually,鈥� Damian said. 鈥淭hey just ask one child 鈥� usually the oldest, 鈥楢re you more conscientious than your siblings?鈥欌��

The problem with this, she explains, is that 鈥渢he oldest child is always older.鈥澛�

鈥淧eople say, 鈥楤ut my oldest kid is more responsible than my youngest kid.鈥� Yes, and they鈥檙e also older,鈥� Damian said.聽

Damian and Roberts also examined a subset of families within the study, all of whom had exactly three children and two parents living under the same roof, in the hopes of revealing significant differences between the oldest, middle, and youngest siblings. But these differences were also 鈥渕iniscule,鈥� according to Roberts.聽

Ultimately, Damian says, 鈥渂irth order probably should not influence your parenting, because it鈥檚 not meaningfully related to your kid鈥檚 personality or IQ.鈥澛�