Hitting children teaches them that "might makes right."
Parents are physically bigger and stronger than children. They also know more than children and, because their brains are fully developed, they are capable of greater
self-control.
When a parent tries to get children to behave better by hitting them, that parent is telling them that hitting people who are smaller and weaker than you is an acceptable way of getting what you want from them. Why should it surprise that parent when their children beat up smaller children at school or grow up to be wife beaters?
Hitting your children may stop their bad behavior but will damage them and your relationship in the long run.
People who believe "sparing the rod spoils the child" typically dismiss the enormous body of research showing that hitting children turns them into angry, resentful adults with psychological and emotional problems.
A large meta-analysis of studies on the effects of punishment found that the more physical punishment children receive, the more defiant they are toward parents and authorities, the poorer their relationships with parents, the more likely they are to report hitting a dating partner or spouse. They are also more likely to suffer mental health problems, such as anxiety, depression, and substance abuse problems, and less likely to empathize with others or internalize norms of moral behavior.
A rational person changes his or her beliefs when reality turns out to contradict those beliefs.
The data show that punishment must be age-appropriate, and must be used when appropriate. Mild spanks may be acceptable for children aged 2-6, older children should be disciplined in nonviolent ways, and parents with anger issues or abusive tendencies should avoid physical discipline entirely. According to
national statistics, nearly 125,000 children were victims of physical abuse serious enough to warrant medical care in 2012, and 42% of those victims were under the age of 6.
Even when using physical punishment on a young child, you must be sure punishment is really called for in the circumstances. I once saw a father and young son (about age 5) bicycling along a busy road, the father following the son. The father was beside himself with rage because his son simply would not keep his mind on the road. Everything seemed to distract him. The father finally lost it, pulled his son off his bicycle, and swatted him hard on the bottom. "What you're doing is dangerous", he yelled, "You could be killed! You have to pay
attention!" What the father failed to understand is that his young son was not capable of ignoring all of those distractions. His son was getting punished for failing to do something he was incapable of doing. A child that age is more capable of following someone on a bicycle than leading. The reason for this is biological: Self-control and focus is the function of the brain's frontal lobes, and the frontal lobes are not fully developed or fully connected to the rest of the brain until early adulthood.