"Eighty percent of success is showing up." Or so goes the old saying. But what do we really mean by this? And how does "showing up" in life -- or, if you prefer, exhibiting "perseverance" -- relate to things like intellect, talent, tenacity, drive, discipline, and so on? On this installment of ST, our guest is Dr. Angela Duckworth, a 2013 MacArthur Fellow and professor of psychology at the University of Pennsylvania who has advised the White House, the World Bank, and both NBA and NFL teams.