My 4-year-old niece doesn't understand yet the difference between not seeing and not being seen: when she wants to hide from someone, she simply closes her eyes, and that's it.
For example, when somebody comes home she likes playing the "Let's pretend I'm not here" game, and then... Sometimes she hides properly, for example under a table, but other times she simply covers her eyes with her hands, or buries her face into the couch, and just stays there, in plain sight. Clearly, she is following the rule "If I can't see you, you can't see me". When will she realize what it really means to hide? Given her ability to speak, play, draw, and do everything, I'd expect her to know better. Clearly, I'm wrong, and I'm not worried by this, but I'm still curious about how long this will continue.
I've found an article explaining that this is done by pre-schoolers, but it doesn't clarify how long it lasts, and "when they go to school" seems way too late (but of course I might be wrong!)
So, what age do children realize that covering their eyes does not mean to hide?