Researchers are learning more about the precise ways paintings and other works of art help patients and families in the healing process. With studies showing a direct link between the content of images and the brain's reaction to pain, stress, and anxiety, hospitals are considering and choosing artworks based on the evidence and giving it a higher priority than merely decoration for sterile rooms and corridors.

"These are not just accoutrements or aesthetics anymore," says Lisa Harris, a nephrologist and chief executive...