Last month, researchers at Duke University and Washington University in St. Louis released a study suggesting that oldest children are smarter than their younger siblings.
The conclusions found that first-born children have higher IQs, perform better in school and are all-around more accomplished than their little brothers and sisters.
Well, in a paper titled Strategic Parenting, Birth Order and School Performance, economists Joseph Hotz and Juan Pantano theorized that it's because parents are more demanding with their oldest than they are with those who were born later.
They are more involved in schoolwork, more likely to punish the child for bad grades and more likely to establish a set of strict rules that must be followed.
I can tell you from personal experience as an oldest child - my parents were WAY more lax with my younger siblings.