Research from the University of Essex has found that firstborn daughters are most likely to achieve academic success.
The British university separated more than 3500 people into 1500 different sibling groups, and their findings fall in line with the widespread belief that birth order affects academic success. Eldest children were 7% more likely to pursue advanced degrees, and 16% had a higher probability of receiving those degrees.
However, the results were somewhat surprising regarding gender. Firstborn daughters were 13% more ambitious than their male counterparts, and girls were 4% more likely to have achieved greater education than their siblings.
Researcher Feifei Bu acknowledged that while her findings are commonly held beliefs, people should be careful with her findings, as the study was U.K.-based and therefore not representative of all people. She also noted that it was specific toward educational goals and success.
“My results show that this educational advantage can be partially explained by the fact that they tend to have higher aspirations than their later-born siblings,” Bu told Business Insider. “My results confirm that adolescents’ educational aspiration has a significant impact on their educational attainment in later life.”
So why do we believe that firstborns are more likely to be successful, and why does it often prove to be true? One theory popularized in the 1970s is the “confluence theory” which states that a child’s intellectual development is shaped by their environment. The more kids that enter a family, the more diluted the household’s intellect can become.
A more popular theory is that parents try to invest the same amount of attention to each kid but can’t when they’re spread thin. The eldest, who are the only kids to receive undivided attention, end up getting the most investment.
But whatever the reason, Bu believes it comes down to a first-come-first-serve process.
“The advantage of being the firstborn is that one is able to choose one’s ‘niche’ first,” she says, “without reference to the roles already adopted by other siblings.