Have you ever-played hide and seek with a child? You hide the come and find you and vise versa. Now have you ever played it with a baby? With a baby they can’t go hide so instead you hide an object under a blanket or something. I played this game with my baby cousin when he was 4 months old. He would watch me hide the object and then not have a clue as to where it went. I recently was playing it with him and he is now 9 months. This time when he watched me place the object behind the blanket he realized the object was gone and actually tried to find it this time. The reasoning for this is that now that my cousin is 9 months old he has reached the sensorimotor stage that allows him to find a hidden object, and he now knows object permanence.