The findings, published by the journal Social Development, suggest that a harshly punitive environment may have long-term detrimental effects on children's verbal intelligence and their executive-functioning ability. As a result, children exposed to a harshly punitive environment may be at risk for behavioral problems related to deficits in executive-functioning, the study indicates.

The study -- by Prof. Victoria Talwar of McGill University, Prof. Stephanie M. Carlson of the University of Minnesota, and Prof. Kang Lee of the University of Toronto, involved 63 children in kindergarten or first grade at two West African private schools. Their families lived in the same urban neighborhood. The parents were largely civil servants, professionals and merchants.

In one school, discipline in the form of beating with a stick, slapping of the head, and pinching was administered publicly and routinely for offenses ranging from forgetting a pencil to being disruptive in class. In the other school, children were disciplined for similar offenses with the use of time-outs and verbal reprimands.

While overall performance on the executive-functioning tasks was similar in the younger children from both schools, the Grade 1 children in the non-punitive school scored significantly higher than those in the punitive school. These results are consistent with research findings that punitive discipline may make children immediately compliant -- but may reduce the likelihood that they will internalize rules and standards. That, in turn, may result in lower self-control as children get older.

"This study demonstrates that corporal punishment does not teach children how to behave or improve their learning," Prof. Talwar said. "In the short term, it may not have any negative effects; but if relied upon over time it does not support children's problem-solving skills, or their abilities to inhibit inappropriate behaviour or to learn."

Despite the age-old debate over the effects of corporal punishment, few studies have examined the effects on executive-functioning ability. This new study uses a quasi-experimental design to derive data from a naturally occurring situation in which children were exposed to two different disciplinary environments. The parents of children in both schools endorsed physical punishment equally, suggesting that the school environment can account for the differences found.

There are many further questions that remain unanswered. "We are now examining whether being in a punitive environment day in and day out will have other negative impacts on children such as lying or other covert antisocial behaviors. Also, we are pursuing the long term consequences of experiencing corporal punishment. For example, what would children's cognitive and social development be 5 or 10 years down the road?," said Prof. Kang Lee.

The findings are relevant to current controversy. "In the U.S., 19 states still allow corporal punishment in schools, although more of them are now asking for parent permission to use it. With this new evidence that the practice might actually undermine children's cognitive skills needed for self-control and learning, parents and policy makers can be better informed," said Prof. Stephanie M. Carlson.