www.newscientist.com/article/2151013-scotland-has-banned-smacking-children-so-should-everyone-else/
"there is no good evidence that smacking will benefit a child. Parents might find that children are more obedient if they fear another smack, but this effect is only temporary. In the long run, children who are smacked are more likely to misbehave, and to engage in delinquent, criminal or antisocial behaviour. Worse, they are more likely to develop mental illnesses.
The science isn’t even new. Smacking is thought to be the most studied aspect of parental behaviour, with reams of research published since the 1960s. Almost all of it finds that physically punishing children can have disastrous consequences in later life.
Future harm
At least five meta-analyses have been conducted on the effects of smacking, assessing around 200 individual studies overall. They show that parents who smack their children are unsurprisingly less likely to have a good relationship with them. And children who are spanked are more likely to experience emotional and physical abuse and neglect.
These studies also find that smacked children are more likely to go on to be aggressive themselves – initially with their peers, and later with their own children and partners. People who were smacked as children are also at a higher risk of having low self-esteem, depression or alcohol dependency.
Earlier this year, a group of psychiatrists in the US claimed that spanking was so harmful, it should be considered an “adverse childhood experience”, alongside neglect and having a parent in prison."