How To Have Smart Children: Firstborn Kids Have Higher IQ Scores Than Their Siblings, Study Says

Firstborn children are often awarded the biggest and the best of everything during their childhoods, especially when compared to their fellow siblings: from more bountiful photo albums of their lives, to outlandish birthday parties and the largest stockpile of baby shower gifts out of any child in the family. The firstborn tends to have it good — that's just a fact of life.

All that extra attention parents give to their oldest son or daughter during the early stages of development might also provide them yet another advantage: a new study shows firstborn children are smarter and score higher on critical thinking skills assessments than their siblings, thanks to additional mental stimulation from their parents.

Researchers at the University of Edinburgh, the Analysis Group and the University of Sydney observed changes in IQ scores and thinking skills in nearly 5,000 children, ages ranging from pre-birth to 14-year-old, every two years.

The report published Wednesday in the Journal of Human Resources reveals parents typically introduced more mentally engaging activities to their first child, offering greater advantages as early as one-year-old, including more support along the way with developmental tasks. Firstborn children typically scored higher on IQ tests and a range of developmental skills assessments, including vocabulary and reading recognition, than their sibling counterparts when tested at the same age.

"Our results suggests that broad shifts in parental behavior are a plausible explanation for the observed birth order differences in education and labor outcomes," Dr. Ana Nuevo-Chiquero, a researcher at the University of Edinburgh School of Economics where the study was conducted, said in a statement.

The research essentially supports the "birth order effect" — a long-studied theory on how the order of birth has a profound impact on psychological and personal development. Researchers noted parents were less likely to provide latter-born children with mentally stimulating activity, offered less support in their development of critical skills and were even more likely to engage in high-risk activity when pregnant with their latter-born children.

Researchers noted a firstborn child could eventually be more likely to earn higher wages and more education than their siblings, according to their findings.

"The findings showed that advantages enjoyed by firstborn siblings start very early in life – from just after birth to three years of age," the study's authors wrote.