Your Chances Of Doing Well At School Are Higher If Your Older Sibling Did Well Too

Your chances of doing well at school and choosing to stay on in education are higher if you have an older sibling who also does well, according to a new study.

But the link between siblings and educational success does not hold for first-born children, suggesting a role for nurture alongside nature in predicting attainment.

There is growing evidence of the role that genes play in the link between parents’ educational achievement and that of their offspring; much less well-known is the extent to which siblings affect each other.

Now researchers have found evidence that older siblings may influence the educational achievement of younger siblings.

Using data from the U.K. Biobank, a biomedical database containing information from half a million participants, researchers aimed to investigate the extent to which having siblings affected how well individuals did at school.

The time that students spent in education was used as a measure of educational attainment by the team, comprising researchers from Bristol University in the U.K., the University of Queensland in Australia and the Norwegian University of Science and Technology.

Those with older siblings were compared with those who had no siblings – singletons. The team also checked for any association between having siblings and an individual’s height and BMI.

The results showed that while height and BMI associations were consistent, the association with educational achievement was larger among non-singletons than among the singletons.

In other words, having siblings influences educational achievement, on top of the genetic association you would expect between members of the same family.

Cross-checking the findings with birth order data showed that the difference in educational achievement was driven by those with older siblings, rather than firstborns.

The link between siblings and attainment was substantially reduced in larger families, those with six children or more, but in families of fewer than six children, the more older siblings an individual had the bigger the impact.

Previous studies suggested that singletons and firstborns were likely to receive more parental input into their education than younger siblings, but the team’s findings suggest the impact of this is much smaller than the impact of having an older sibling do well at school.

Alternative explanations for the link between older siblings and educational attainment include factors that could influence the number of children in a family, such as socio-economic position. Birth order could also influence how an individual is affected by their parents.

But these were unlikely to explain the differences observed in the data, according to the researchers.

“A more plausible explanation for the difference in association of education and the educational attainment… between firstborns and non-firstborns is that older siblings influence the educational decisions of younger siblings.

“Whereas an individual’s decision to go to university is less likely to be strongly influenced by younger siblings,” the researchers said.

This could be the result of the imitation effect, as younger children seek to follow in the footsteps of older siblings. There could also a more subtle impact of a higher-achieving older sibling, such as helping younger siblings with their homework.

The team acknowledge, however, that their findings may be affected by selection bias: participants in the Biobank are volunteers rather than randomly chosen.

They were also unable to account for the effect of half-siblings, for differences across generations, or whether the effect varied according to the sex of the individuals, whether the influence was stronger in same-sex pairs, for example.

There may also be systematic differences between singleton and non-singleton children that could skew the results.

But the findings add to the evidence of the social effect of genetic variation, and of how our siblings can influence our own success.