Why First-Borns are Smarter and Richer

The headline above is probably music to some ears, but not so much for others...

Recently published findings are the first to suggest advantages of first born siblings start very early in life - around zero to three years old.

To put it simply, research has observed parents changing their behaviour as new children are born. As a result, they offer less cognitive stimulation to children of higher birth order (those who are born later on).

Those born and raised in high-income countries such as the United States, the UK and Norway, earlier-born children enjoy higher wages and education as adults - known as the "birth order effect".

Comparing two siblings, the greater the difference in their birth order, the greater the relative benefit to the older child.

But why? 

To date we've had no evidence that explains where such differences come from. While it makes sense that parents earn more money and gain experience as they get older and have more children, they also need to divide their economic resources and attention among any children that arrive after the first born.

The researchers wondered where in childhood these differences began, and what the cause or causes might be.

Using an assessment tool called the Home Observation Measurement of the Environment, provided a measure of the quality of the cognitive stimulation and emotional support provided by a child's family.

Resarch found that children of higher order of birth - that is, those born second, third or further on from the first child - receive less quality parental cognitive stimulation. 

Furthermore, this shift in parental behaviour appears to start in the womb. In pregnancies subsequent to their first, we found that mothers are less likely to reduce drinking and smoking or seek timely prenatal care. Once born, non-first-born babies are breastfed less often.

The findings suggest that a plausible explanation for the negative relation between birth order and educational achievement is a broad shift in parenting, especially with respect to parents' ability to foster early cognitive development.

In summary, these changes in parental behaviour appear to set later born children on a lower path for cognitive development and academic achievement, with lasting impact on adult economic outcomes.

But for most parents, it is probably not difficult to understand how and why parenting focus and behaviour changes with later-born children!

Marian Vidal-Fernandez is Senior Lecturer in Economics, at the University of Sydney and Ana Nuevo-Chiquero, Lecturer, University of Edinburgh

This article was originally published on The Conversation. Read the original article.