Sometimes school choice means choosing to place a child in an environment outside his comfort zone. The documentary “American Promise” chronicles the experiences of two young black boys who attended The Dalton School, a rigorous, predominantly white private school in New York. The two walk away from the campus–one as a six grader, the other a high school graduate–with a valuable lesson about portraying and cherishing their own racial identity. The parents also learn an important lesson about engineering the perfect academic experience for their sons. The film airs tonight on PBS.