As Occupy movement protests helped push spiraling college costs into the national spotlight, Education Secretary Arne Duncan urged higher-education officials Tuesday to “think more creatively — and with much greater urgency” about ways to contain costs and reduce student debt. The Education Department characterized Mr. Duncan’s remarks, at a Las Vegas conference of college financial aid workers, as the start of a “national conversation” about high costs, which have prompted raucous protests across the country and ignited an angry push among some borrowers demanding debt forgiveness, federal grants and interest-free loans.