Psychologists have long known that children who have been beaten are prone to low self-esteem and insecurity in later life. Little research has been done, though, into the effects of scolding.

"The feeling of self-respect is hurt when you are punished in one way or another," said the researcher who carried out the new study, Erik Sigsgaard of the Danish Center for Research in Institutions.

As part of the study, children at a nursery were observed and interviewed in the 1994-2002 period.

More than half said they hated to be shouted at and believed the grown-up was still angry with them, even long afterwards. The children often felt upset even when parents and teachers did not think they had scolded them, the study found.

"You can't say that it's better to scold your child than to beat (them). When you punish a child you give (them) the feeling that (he or she) isn't worth anything," Sigsgaard told Reuters.

One boy said that scolding is when somebody beats you with his voice. Children see little difference between physical and verbal violence, Sigsgaard explained.

Damaged self-esteem, problems in relating to others and forming close relationships are the most common problems faced by abused children.

Although parental smacking has become less common, and even illegal in some countries, most parents and teachers shout at disobedient children, both in private and in public.

According to the United Nations, child rights convention, children have the right to protection from physical and psychological violence and abuse.

Sigsgaard advised parents to tell their children their opinion in a normal voice without shouting.

"Parents who want to keep a close relation with their children should not scold too much, or they will soon be alone. It's silly because we are pushing away what is dearest to us," Sigsgaard said.