I feel this must be a developmental phase in order to be sure an object exists though out of view- or something to that effect.
For the last three weeks or so, my 9 month old son hide toys/objects out of his view and then brings then back (he's a magician!!). At first I didn't catch on but then I realized what he was doing.
Sometimes he will let go of the item, other times maintain the grip on it as it is out of his view. He hides them under furniture, behind furniture, beneath the baby tub while he is bathing (I hold him otherwise he may go over the side!).
I have Dorothy Einon's book Early Learning but I have not been able to find this phase though I am sure she writes about it.
It is interesting to watch, can anyone tell me more about it?