A new study shows that first-born children tend to be more intelligent, do better in school, and earn more income than younger siblings.

The study of over 20,000 individuals suggests that parents give special attention to forming the thinking skills of their first-born child. While the younger offsprings receive less support in this area.

Confirming the suspicions of eldest brothers and sisters everywhere, University of Edinburgh economists found first-borns achieve higher IQ test scores from as young as one year old.

The researchers, collaborating with a team from from Sydney University, examined data from children who were given reading and picture vocabulary tests every two years.

By analysing the results in relation to parental behaviour, they found first-borns were given more support with tasks that involve thinking, and subsequently scored better on the tests.

The differences in test scores increased slightly with age, according to the study published in the Journal of Human Resources, which looked at children’s mental progress from pre-birth to age 14.

All children were found to receive the same level of emotional support, but parents appeared to spend less time on brain-stimulating activities with their younger children, took part in fewer activities with them such as reading, crafts and music.

Parents were also more likely to take increased risks, such as smoking more, after the birth of their second child.

Parents tend to shower more attention and support on their first offspring. They may have given the first-born child more educational resources, resulting in better cognitive thinking skills.