Researchers have both speculated and studied how birth order affects kids' personalities in the past, but one study out of the United Kingdom has found that firstborns may have an educational advantage over their younger siblings.
Researchers at the University of Essex's Institute for Social and Economic Research surveyed 3,553 individuals and 1,503 groups of siblings, and discovered that firstborn children tended to have higher educational aspirations and attainment (level of education completed). Only-children and first-born twins were excluded from the study.
For each family involved in the study, researcher Feifei Bu examined sibling birth order, number of children in the family, age spacing, sex, health, relationships with one another and educational aspirations. She found that firstborns had a greater probability -- 16 percent higher -- of attending further education, compared with later-born siblings.
"The advantage of firstborns in educational outcomes may be partially explained by the fact that firstborns tend to have higher aspirations which push them toward high education levels," Bu wrote in the published study.
She further explained to The Guardian that parenting could play a role. "It could be that the parents simply devote more time and energy to them -- it could be they are actually more intelligent. For me, I tend to lean towards the theory that parental investment is possibly at work here," she said.
But she also found age-spacing to be a contributing factor. The further apart in age the siblings -- for example, a six-year instead of one-year difference -- the more likely both kids were to be successful. The idea is that with widely spaced siblings, parents have the ability to spread out their resources. In other words, they have time to give each child more time and money.