36 to 42 Months
Imagine that! Your child’s imagination is taking off when he’s playing alone and with others: “Let's go to the moon!” “This isn’t a chair. It’s my car.” You may even be introduced to a friend only your child can see. But imagination is more than simple play when you look deeper. It can help a child talk about the future or other places and times (history, for example) as he grows. A healthy imagination may even help a child develop empathy—he can imagine how someone else feels.
“Caring for Your Baby and Young Child, Birth to Age 5 (5th Ed)” by the American Academy of Pediatrics.