New research published in the journal Child Development shows that around 17 percent of children ages 8 to 12 create incredibly complex imaginary worlds, known as paracosms. The findings reveal the phenomenon is far more common than previously believed. The creation of such paracosms, as the imaginary worlds were first labeled in a 1976 study, is nothing to worry about, said the project's lead author Dr. Marjorie Taylor, a professor emeritus of psychology at the University of Oregon. "It's a positive thing associated with creativity and storytelling, and it's not particularly rare," said Taylor, who has been studying children's imaginary friends and paracosms for about 25 years. "These are kids who are coming up with very complex stories that they really enjoy and that many will share with others." Early studies on paracosms primarily focused on adult memories of their childhoods. In the 1992 book "The Development of Imagination: The Private Worlds of Childhood," authors David Cohen