Here is a short audio piece from the popular radio show “Here and Now” discussing the benefits of arts integration at a Maryland school. While the piece focuses primarily on the use of music in the classroom, the more extended version of article (available here) explores in greater detail some of the known benefits of overall integration of arts in schools.
A wealth of research shows arts integration helps kids increase their problem-solving skills, enhance their social development, and remember the material better. Scientific studies show the use of arts in education engages the whole brain, improving retention.
For those looking to learn more about research behind the benefits of arts integration in schools, a good starting place is the Arts Education Partnership (quoted in the article) and the National Endowment for the Arts.