Science has just confirmed what older siblings reckon they knew all along: that first-born children are more intelligent than their younger siblings.

Finally settling the age-old debate about whether birth order really influences a child’s intelligence, researchers at the University of Edinburgh found that older siblings scored higher on IQ tests than their younger brothers or sisters.

And the differences in intelligence were obvious even from their first birthdays, with older siblings getting higher scores on a range of tests including reading, picture vocabulary tests and letter matching.

The researchers, who assessed almost 5,000 children every two years from birth to the age of 14, attributed this higher intelligence to older children getting more mental stimulation from their parents than their younger siblings.

They found that parents engaged in fewer activities with their children the more they had, meaning they did things like reading and making crafts with their oldest child more than their younger siblings.

Read more: Eldest siblings are smarter, nicer and more outgoing

In the study, published in The Journal of Human Resources, Dr Ana Nuevo-Chiquero, of Edinburgh University’s school of economics, concluded, “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.”

This new research could help explain the “birth order effect”, which sees older children go on to have higher wages and more education in later life compared to their younger siblings.

However, it’s not all bad for younger siblings: recent research has also suggested that they might be funnier and more laidback than their cleverer older brothers and sisters.

And, happily, the new study also showed that parents gave the same level of emotional support to all their children, regardless of age.

So at least there’s that.