Douglas's teaching assistant had made a note in his school diary - which details work the pupils have done during the day - informing his mother that he had been upset by a film.
Every song is a scribbled note in the margin of a diary and the music of our lives becomes a soundtrack to the emotional scrapbooks we keep in our heads.
Working with 400 school children aged between nine and 11, the team assigned whole classrooms either to perform and note down three kind acts per week or - as a control group - to keep a diary of three locations they visited each week.