Younger kids benefit from smart older siblings

If you have an older brother or sister who seemed to have all the brains growing up and left you feeling overshadowed, it turns out you may have reason to thank them. A new study from the University of Essex finds there is a "spillover" effect when an older child does well in school that could be equivalent of investing thousands of dollars in extra education for the younger siblings.

The Garg family in Lorton, Virginia, are case in point. The three boys like to play word games around the dinner table, and while their parents say the kids are all very bright, it's 8-year-old Syan who excels most at school. And the family has observed that his two brothers are benefiting greatly as a result.

"Teachers have commented, you know, 'Kamryn's picking up math well, and I attribute that to Syan's help,'" their mother Rachana Garg, told CBS News.

Richard Lanthier, an associate professor of human development at George Washington University, said the effect is strongest when the siblings get along.

"If the sibling is smarter and the younger one emulates them, imitates them, then they're going to have performance that is similar," Lanthier told CBS News.

However, the study found that the effect does not work in reverse; intellectual improvement in younger siblings did not benefit an older child. The spillover effect was found to be larger for siblings in poorer families living in low-income neighborhoods, and in those speaking a language at home other than English.