In the early and mid-20th centuries this was a form of bowdlerisation, concerned with some of the more violent elements of nursery rhymes and led to the formation of organisations like the British 'Society for Nursery Rhyme Reform'. Psychoanalysts such as Bruno Bettelheim strongly criticized this revisionism, on the grounds that it weakened their usefulness to both children and adults as ways of symbolically resolving issues and it has been argued that revised versions may not perform the functions of catharsis for children, or allow them to imaginatively deal with violence and danger.