In most cases, yes, it is OK for a toddler to have imaginary friends. It is part of the way their brains mature. At about age 3 they may not be able to tell reality from their imagination.
There is also some evidence linking pretend play with executive function. Teacher directed play is an effective learning tool, but some studies indicate that the most effective type of pretend play could be child-directed, where the kids spontaneously start pretending they are characters in a situation and act out their roles.
You can encourage the process by first identifying an interest that all the kids involved have in common, and then suggesting, “Hey, why don’t you guys play Frozen?” You can choose a movie or show they are both (or all) familiar with, but if they haven’t been exposed to much screen time, they can have a pretend dinner, birthday party, a teacher in a classroom, or any other live event. Just beware of letting them practice violent situations by playing something like cowboys and Indians or cops and robbers.
If your child is alone, you can encourage pretend play with stuffed animals or even imaginary friends. At 3 years of age your child’s imagination seems real to her. At 5, she should be able to distinguish imagination from reality.
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