Dynamic complementarity in skill production: Evidence from genetic endowments and birth order

Download Publication (PDF)

This study looks at how nature and nurture interact in influencing individuals academic attainment, and finds support for the theory that early life parental inputs increase later gains – especially in those children who have genetic advantages.

The researchers used data on a sample of 15,000 siblings, whose genetic and demographic information is stored in the UK Biobank biomedical database, to look at whether firstborn children – who usually have greater parental inputs in their early years than later siblings – had an added educational gain from those inputs if they also had genetic characteristics associated with high educational achievement.

The researchers measured these genetic factors using a “polygenic score” which is a DNA-based indicator of propensity to succeed in education.

They found children with high polygenic scores benefited disproportionally more from being firstborn. Conversely, firstborn children with below-average polygenic scores did not gain an advantage in terms of educational attainment compared to their later born siblings.

As children’s genetic heritage is not affected by whether or not they are a firstborn, the study builds on earlier research which suggests firstborn children do better at school because they get more parental attention than their younger siblings. It supports the existence of an interplay between nature and nurture in determining educational attainment later in life.

The  authors conclude that their study provides an important precursor to more detailed modelling of how parental decisions about time and financial inputs with different children play out in their later lives.