From Nick Rabkin writing for Huffington Post:
When students study the arts, they develop their abilities to be creative, plan, explain their thoughts, work together effectively, build theories, make predictions, create analogies, solve complex problems and assess their own work. These are commonly understood as “21st-century skills.” What's more, a growing body of research has also shown that arts education correlates strongly with basic competencies — literacy and numeracy — and a wide range of other positive outcomes for young people. The bottom line is that children who have more arts education do better in school and in life. Significantly, the correlation happens to be strongest for low-income youth, the students most often failed by our schools.