Adults are only less superstitious than children in proportion as they have more power over their environment. In predicaments where everyone is powerless (eg war, gambling) everyone is superstitious
Notes from Wikiquote
The Collected Essays, Journalism & Letters, George Orwell: My Country Right or Left, 1940–1943, Editors: Sonia Orwell, Ian Angus. p. 9 (footnote)