Three recent, widely reported studies on spanking children claimed to show that the disciplinary practice impairs cognitive development in children. Together, they held out the promise of providing the latest, definitive word on a passionate debate, says the Wall Street Journal.
Statistical analyses of spanking's effects on cognition are clouded by many complicating factors, says the Journal:
* Effects can be attributed to the wrong cause, statisticians say; rather than spanking causing problems in children, it is possible that their existing cognitive problems can make spanking more likely.
* Moreover, any effects of spanking are difficult to measure and probably small.
* And unlike, say, a study on prescription drugs that removes a misleading placebo effect, no ethical study can assign some children to be spanked; instead, parents must be trusted to remember and share their disciplinary practices.
The most methodologically sound of the new studies was conducted by Lisa J. Berlin, a developmental psychologist at Duke University, says the Journal. She and her co-authors examined survey and observational data about 2,573 low-income toddlers, tracking the punishment they received and their scores on cognitive exams at ages 1, 2 and 3:
* They found that kids with underlying problems such as aggressive behavior aren't later spanked more frequently; so the point of criticism of many studies -- that problems cause spanking and not the other way around -- is addressed in this research.
* Researchers however noted that the study didn't remove all possible explanations for why some children develop faster than others, such as their parents' intelligence.
Other research conducted by Murray Straus, a sociologist at the University of New Hampshire and an outspoken anti-spanking advocate, involved the examination of how 1,510 children were disciplined and how they scored on standardized cognition tests:
* Children aged 2 to 4 who weren't spanked gained an average of five points, equivalent to points on an IQ test, four years later compared with those who had been spanked three times or more per week.
* The study was criticized for failing to dispense with an alternative explanation for reasons why some kids scored lower on cognitive tests.
"It also could be that kids who got spanked more...were already developing at a slower rate," says Marjorie Gunnoe, a professor of psychology at Calvin College in Grand Rapids, Mich.
Source: Carl Bialik, "New Research on Spanking Might Need a Time Out," Wall Street Journal, October 14, 2009.
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