Not enough studies have been done yet to ascertain what’s actually occurring in the brain while children are engaging in this sort of play. But Laura Phillips, a neuropsychologist with the Child Mind Institute in New York City, says scientists can look to what’s going on in adult brains when they’re in creative problem-solving mode. Based on MRI research, Russ says, mind-wandering and improvisation activate a different area of the brain from logical, critical thinking. When adults are trying to solve a problem, they go back and forth between these modes.