A fter Daisy Fancourt’s daughter Daphne was born prematurely, she was confined to an incubator, fighting for her life against a series of infections. Unable to touch her baby or even properly enter the room, Fancourt kept vigil just inside the door, dressed head to toe in PPE, singing lullabies over the whir of instruments and alarms. The songs calmed her, and may have been crucial for Daphne too. Studies show that singing to babies in intensive care reduces their heart rate, improves their breathing, and encourages them to feed. It was a moment when Fancourt’s professional and personal lives collided. A professor of psychobiology and epidemiology at University College London, she researches how social connections and behaviours affect our health. In Art Cure, her first book for a popular audience, she aims to make a scientific case that the arts – from playing music to theatre-going to painting – aren’t a merely aesthetic aspect of life.…