our son started banging his head when he was upset when he was really little (maybe about 6 months old), I ignored it because I figured he would put two and two together and realize he was hurting himself and stop. However, he is 17 months old now and still doing it. The difference now being that he has started leaving bruises (multiple times). When he gets angry he will run his head into whatever is nearest it seems, whether that be the floor, the couch, or the coffee table. I've been told I need to just spank him every time he does it but it seems like I would be spanking him all day long. What can I do to make him stop?