If you really want your child to excel in life the answer is not to teach them a difficult language or complicated maths - but to play silly jokes.
Taking time out to clown around helps youngsters to make friends and think more creatively, researchers say.
Playing "let's pretend" is also a vital way for them to learn important skills, they argue.
Researchers from Sheffield University discovered the importance of both "silly play" and imaginative play during tests on children aged 16 to 24 months.
Jokes included an adult putting a toy chicken on their head, while fantasy games involved activities like pretending to wash hands without soap or water.