Research has shown that children exposed to diverse books, especially those that have cross-racial groups, have better acceptance of children of other ethnicities as compared to those not exposed to diverse books.
When you look at the picture books used in your classroom, do they represent a variety of voices? Do they represent a box of eight crayons, or a box of 64? Are they telling stories just about hardship, or do they celebrate the characters' cultures? Are they giving students a mirror to their own experience, as well as windows into other lives?