The researchers said “Underachievement among American youth is often blamed on inadequate teachers, boring textbooks, and large class sizes. We suggest another reason for students falling short of their intellectual potential: their failure to exercise self-discipline”.

Angela L. Duckworth and Martin E.P. Seligman; “Self-Discipline Outdoes IQ in Predicting Academic Performance of Adolescents”; Positive Psychology Center, University of Pennsylvania, 3701 Market St., Suite 200, Philadelphia, PA 19104;