Children who were spanked in childhood have lower IQ , a study finds. The more the children were spanked, the lower their IQ, research also found. The probable reason is that spanking is highly stressful for children and it can leave them with post traumatic stress disorder. Parents who continue to use corporal punishment to teenage years may hamper their children's brain development even more. The parents who use corporal punishment as a means to discipline their children need to correct themselves. They are damaging the mental growth of their children. They are victim of a poor emotional IQ and need to improve it so that they tackle their children by understanding them and not by punishing them.