Like an online retailer trying to woo a customer back by offering a 10% discount on the boots they’ve been eyeing, education researcher Angela Duckworth wanted to understand how to incentivize ...

Mr. Seo, a parent in his 40s living in Gwacheon, Gyeonggi Province, solves elementary and middle school math workbooks every day. This is to help his fourth-grade son, who attends a math academy ...