The classic study involving the Bobo Doll is an example of media influence that I remember discussing in my Psychology class. The study started out with two different groups of nursery children with a bunch of toys they had never seen before. One of the toys was a Bobo Clown with a weighted base that was designed like a punching bag toy. One group of children observed an adult playing gently and quietly with toys and ignoring Bobo. In the other group of children, an adult took agression out on the doll. The adult punched Bobo in the nose, sat on its head, used a toy mallet to hit it, and even kicked it in the air. After leaving both groups of children alone, those that observed the adult acting aggresively toward the doll imitated many of the same moves. http://en.wikipedia.org/wiki/Media_influence
Young children are very easy to influence. When they see adults acting a certain way or saying certain words, they assume it's okay for them to do also.