Ice Age, Shrek, Ratatouille, Up, The Incredibles. On the face of it, they’re fun children’s films with colourful, animated characters and lots of visual gags. But there are also things that adults will enjoy: complex jokes, cultural references and backdrops that include adult-related topics and themes based on politics, history or modern culture. This is known as “The Simpsons effect” – making animated films as much about entertaining parents as children.