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Spanking is harmful for kids' intelligence: Study

The strongest link between hitting and IQ was found among those surveyed children whose parents continued to use corporal punishment even when they were teenagers

Los Angeles, September 25 -- Spanking by parents can significantly damage a child’s mental abilities and results in a lower IQ later in life, suggests a new groundbreaking study by researchers at the University of New Hampshire.

Parents generally use spanking in order to teach children not to do forbidden things or to stop them quickly when they are being irritating or behaving badly. But, they do not know that this disciplinary measure could hamper their child’s cognitive development.

The latest study suggests that children smacked by their parents grow up with lower IQs than those not physically punished. It shows that the children regularly disciplined with a physical punishment suffer from a form of post-traumatic stress disorder that affects their IQ.

According to University of New Hampshire professor and the lead author of the study, Murray Straus, the relationship between spanking and mental ability is found in children around the world.

"All parents want smart children. This research shows that avoiding spanking and correcting misbehavior in other ways can help that happen," Straus says. "The results of this research have major implications for the well being of children across the globe."

Spanking and IQ in the United States
To reach their findings, Straus and colleagues studied 806 children in the U.S. aged between two and four and 704 children aged between five and nine.

When both groups were retested four years later, researchers found that the U.S. children who were spanked had lower IQs than those who were not spanked.

IQs of children in the first group who were not spanked were 5 points higher four years later than the IQs of those who were spanked. The IQs of children in the other group who were not spanked were 2.8 points higher four years later than the IQs of children the same age who were spanked, Straus’ team found.

"How often parents spanked made a difference. The more spanking, the slower the development of the child's mental ability,” Straus said. “But even small amounts of spanking made a difference."

Spanking and IQ around the world
The research team noticed the same link in children worldwide. The team looked at corporal punishment practices in 32 countries, and found a lower average IQ in nations in which spanking was more prevalent.

Straus and colleagues surveyed 17,404 university students who experienced corporal punishment when they were children. The strongest link between hitting and IQ was found among those surveyed children whose parents continued to use corporal punishment even when they were teenagers.

“Corporal punishment is extremely stressful and can become a chronic stressor for young children,” Straus said. “For many it continues for years and the stress of corporal punishment shows up as an increase in post-traumatic stress symptoms such as being fearful, that terrible things are about to happen and being easily startled.”

"It is time for psychologists to recognize the need to help parents end the use of corporal punishment and incorporate that objective into their teaching and clinical practice. It also is time for the United States to begin making the advantages of not spanking a public health and child welfare focus, and eventually enact federal no-spanking legislation," he concluded.

Straus and colleagues presented their findings today (Sept. 25) at the 14th International Conference on Violence, Abuse and Trauma in San Diego, California.