His study revealed that “kids who were physically punished had up to a five-point lower IQ score than kids who weren’t”. The studies were made among 32 countries and in countries where spanking was applied, the average IQ was lower. Of course, the spanking effects are not visible immediately but have significant consequence on long term. A parent thinks that if he spanks his unruly children, their behavior will be better. And it will be… in that moment, but on long term is just a wrong taken measure.

Murray Straus has interviewed mothers of 1,510 children (806 kids ages 2 to 4 and 704 ages 5 to 9) and three quarters admitted of applying corporal punishment on their children. The researchers measured the initial children’s IQ and again four years later. Results revealed that children who were not spanked, scored better on intelligence test than the other ones. The differences in IQ were 5 points among 2 to 4 years old children and 2.8 points among 5 to 9 years old children.

As a conclusion, parents take good care because “the more spanking the, the slower the development of the child’s mental ability. But even small amounts of spanking made a difference,” Straus says.