Imaginary pals can mean real development.

Byline: Stephanie Dunnewind

SEATTLE _ Be it an invisible girl who lives under the bed, a 7-inch-tall elephant who wears shorts or a green dog, imaginary friends are common childhood companions even into elementary school, researchers from the University of Washington and University of Oregon discovered.

By age 7, more than two-thirds of children reported inventing an imaginary friend at some point in their lives, according to a recent study in the journal Developmental Psychology.

"The main message to parents is how common imaginary friends are, even with children older than previously studied," said UW psychology professor Stephanie Carlson. "Parents shouldn't be concerned if elementary-school-age children still engage in this form of play."

University of Oregon professor Marjorie Taylor wanted to find out how children ditched their…