Maybe every single one of my kids is exceptional but I think at least two, and maybe all three, would have been capable of imitating that behavior for effect (a

Maybe every single one of my kids is exceptional but I think at least two, and maybe all three, would have been capable of imitating that behavior for effect (amusing adults, attempting to amuse themselves in a way they'd observed another kid being amused), with an understanding of exactly what they were imitating, by no later than age two. Without understanding exactly what was going on, they might have managed to simply mimic the behavior some months earlier than that.