First-born children are smarter than their younger siblings, according to new research.
Economists at the University of Edinburgh have waded into the age-old debate and concluded that first-borns have a higher IQ test score than their siblings as early as age one.
Researchers said the findings could be explained by first-born children receiving more mental stimulation and support in developing thinking skills from their parents during their early years.
The findings, published in the Journal of Human Resources, could help explain the so-called birth order effect when older siblings in a family enjoy better wages and more education in later life, according to researchers.
The study, conducted in partnership with Analysis Group and the University of Sydney, examined data from the US Children of the National Longitudinal Survey of Youth collected by the US Bureau of Labour Statistics.
Almost 5,000 children were observed from pre-birth to 14 years old on their family background and economic conditions and assessed every two years on skills including reading and picture vocabulary.
Researchers applied statistical methods to the economic data to analyse how parental behaviour such as smoking and drinking during pregnancy was related to their child's test score.
It was found that mothers took "higher risks" during the pregnancy of latter-born children and parents offered less mental stimulation to younger siblings and took part in fewer activities such as reading, crafts and playing musical instruments.
Dr Ana Nuevo-Chiquero, of the University of Edinburgh's School of Economics, said: "Our results suggest that broad shifts in parental behaviour are a plausible explanation for the observed birth order differences in education and labour market outcomes."
Why are you making commenting on The Herald only available to subscribers?
It should have been a safe space for informed debate, somewhere for readers to discuss issues around the biggest stories of the day, but all too often the below the line comments on most websites have become bogged down by off-topic discussions and abuse.
heraldscotland.com is tackling this problem by allowing only subscribers to comment.
We are doing this to improve the experience for our loyal readers and we believe it will reduce the ability of trolls and troublemakers, who occasionally find their way onto our site, to abuse our journalists and readers. We also hope it will help the comments section fulfil its promise as a part of Scotland's conversation with itself.
We are lucky at The Herald. We are read by an informed, educated readership who can add their knowledge and insights to our stories.
That is invaluable.
We are making the subscriber-only change to support our valued readers, who tell us they don't want the site cluttered up with irrelevant comments, untruths and abuse.
In the past, the journalist’s job was to collect and distribute information to the audience. Technology means that readers can shape a discussion. We look forward to hearing from you on heraldscotland.com
Comments & Moderation
Readers’ comments: You are personally liable for the content of any comments you upload to this website, so please act responsibly. We do not pre-moderate or monitor readers’ comments appearing on our websites, but we do post-moderate in response to complaints we receive or otherwise when a potential problem comes to our attention. You can make a complaint by using the ‘report this post’ link . We may then apply our discretion under the user terms to amend or delete comments.
Post moderation is undertaken full-time 9am-6pm on weekdays, and on a part-time basis outwith those hours.
Read the rules here