Around age 3, children start to develop a vivid imagination. At this age, your preschooler will begin to spend a lot of time in a fantasy world of her own creation. Her dolls and stuffed animals all have names and personalities. She may chat with imaginary friends. Parents sometimes worry that imaginary friends are a sign of loneliness or isolation, but that's not the case. Children use this type of fantasy play to learn how to interact with real people. It's practice for the "real world."