Young children who are spanked by their mothers or fathers show more externalizing behavior and less cognitive capacity several years later, compared with their peers who are not spanked, according to a report published online Oct. 21 in Pediatrics.
This secondary analysis of data from a longitudinal cohort of 1,933 families across the United States could not establish whether spanking exerts a direct effect on cognitive and emotional development "through stress, trauma, or other physiologic or neural processes, or whether spanking is simply an indirect proxy for other unmeasured parenting practices that negatively affect cognitive development." However, all the data in this rigorously controlled analysis point toward a direct effect "that cannot be simply explained away as spanking families being also less likely to speak to or engage their child in ways important for cognitive development," said Michael J. MacKenzie, Ph.D., of Columbia University School of Social Work, New York, and his associates.
These study findings are of particular concern because a full 57% of these children were spanked by their mothers and 40% by their fathers at 3 years of age, and those rates declined only slightly at 5 years of age, the investigators said.
At age 5 years, 52% of the children were spanked by their mothers and 33% by their fathers. Most mothers estimated that they spanked their children less than twice a week, but 5.5% reported spanking two or more times per week. Most fathers said they spanked their children less than twice a week, but 3% reported doing so two or more times per week (Pediatrics 2013 Oct. 21 [doi:10.1542/peds.2013-1227]).
Compared with no spanking, both high-frequency and low-frequency spanking by mothers at ages 3 years and 5 years were strongly associated with significantly higher levels of externalizing behaviors at age 9 years. This association remained robust after the data were adjusted to account for numerous childhood characteristics such as gender, birth weight, birth order within the family, and temperament as a baby, and maternal traits such as age at the child’s birth, marital status, racial/ethnic background, education level, household income-to-needs ratio, life stress, history of depression or anxiety, impulsivity, and cognitive capacity.
In addition, paternal spanking at age 5 years correlated with reduced receptive verbal capacity in the child at age 9 years, an indication of cognitive ability measured via the Peabody Picture Vocabulary Test.
"Future work should focus on providing families a clearer picture of the outcomes associated with spanking and more information about what discipline practices may have the desired effect on improving functioning, so that they can move beyond punishment practices to the incorporation of positive parenting behaviors with the potential to encourage healthy child trajectories," the investigators noted.
The United States "stands out as one of the few high-income countries that have not followed Sweden’s lead in banning spanking," even though experts, including the American Academy of Pediatrics, warn against the practice and recommend other methods of discipline. To date, several studies have reported a link between being spanked and exhibiting adverse behavioral outcomes, but most have not used longitudinal samples, have not accounted for measures of family stress and socioeconomic variables, have examined maternal spanking only, and have not focused on cognitive or developmental outcomes.
Dr. MacKenzie and his colleagues addressed these issues in their study using a longitudinal data set that followed a large and diverse sample of children from birth through age 9 years. They assessed 1,933 children and their families who participated in the Fragile Families and Child Well-Being (FFCW) study, which included a representative sample of children born during 1988-2000 in 20 medium- to large-size cities.
This subset of FFCW participants had more resources and appeared more stable than did the entire cohort, but still represented "a fairly disadvantaged urban sample," the researchers said.
This study was funded by the National Institutes of Health, the Eunice Kennedy Shriver National Institute of Child Health and Human Development, the National Science Foundation, and the Department of Health and Human Services. No financial conflicts of interest were reported.