HomeHeard it on the ShowWhy First Born Children May Be Smarter Than Their Younger SiblingsWhy First Born Children May Be Smarter Than Their Younger SiblingsWed, February 15, 2017 by Tessa Snyder SHARE NOW teen siblings brother and sister grimacing close up portrait. Boy girl siblings grimace. Are the oldest siblings really the smartest? According to a study published in the Journal of Human Resources, firstborn children may have better thinking skills than their siblings because they received more mental stimulation during their early stages of development. CLICK HERE for more from USA TODAY. Listen to Murphy Sam and Jodi: On Demand And while you’re at it… leave a comment and follow us on Facebook, Twitter & Instagram and subscribe to our YouTube channel.