Early Spanking Increases Toddler Aggression, Lowers IQ

By Jennifer Thomas
Read more from Thomas at HealthDay

Children who are spanked as 1-year-olds are more likely to behave aggressively and perform worse on cognitive tests as toddlers than children who are spared the physical punishment, new research shows.

Though the negative effects of spanking were "modest," the study adds to a growing body of literature finding spanking is not good for children.

"Age 1 is a key time for establishing the quality of the parenting and the relationship between parent and the child," said study author Lisa J. Berlin, a research scientist at the Center for Child and Family Policy at Duke University. "Spanking at age 1 reflects a negative dynamic, and increases children's aggression at age 2."

The study is published in the September/October issue of Child Development.

Berlin and her colleagues looked at data on 2,500 white, Mexican American and black children from low-income families. The data included parents' reports about their children's behavior, their use of spanking, as well as home visits by trained observers to document parent-child interactions at ages 1, 2 and 3.

About one-third of mothers of 1-year-olds reported they or someone in their household had spanked their child in the last week, while about half of the mothers of 2- and 3-year-olds reported that their child had been spanked.

The average number of spankings for 1-year-olds was 2.6 per week, while the average for 2-year-olds was three spankings per week.

The study found that children who were spanked at age 1 had more aggressive behaviors at age 2 and performed worse on measures of thinking abilities at age 3.

Being spanked at age 2, however, did not predict more aggressive behaviors at age 3, possibly because the spanking had begun at age 1 and by the age of 2 the kids were already more aggressive, Berlin said.

Researchers also looked at the effects of verbal punishment, defined as yelling, scolding or making derogatory comments. Verbal punishment was not associated with negative effects if the mother was otherwise attentive, loving and supportive.

Researchers controlled for family characteristics such as race, ethnicity, mother's age, education, family income and the child's gender.

Previous research has shown spanking is more common among low-income households than high-income households.

Researchers chose a sample of low-income families because some child behavior experts have argued that when spanking is "cultural normative" -- that is, it's expected for parents to use physical discipline -- the detrimental effects of spanking may be lessened. "We did not find that," Berlin said. "Even in a sample of low-income people where presumably it's more normative to spank your kids, we found negative effects."

The study also found that mothers who said their children were "fussy" babies were more likely to spank them at ages 1, 2 and 3. But children who were more aggressive at 2 were not more likely to get spanked.

"The implication or the suggestion in past arguments is that some kids who are more aggressive or difficult to control might illicit more spanking, but that's not what we found," Berlin said.

Researchers found that black children were spanked and verbally punished the most, possibly because of cultural beliefs about the importance of respecting elders and the value of physical discipline, or because parents feel they have to prepare their children for a racist and potentially dangerous world.

Of all the debates over child-rearing, spanking "definitely touches a nerve," Berlin said.

"It's a parenting practice that has been around for a long time, and one that's also in transition," Berlin said. "In general, the use of spanking is going down. But there is also a contingent of people who really believe in it, who say that's how they were raised and it's a tradition they want to continue."

Elizabeth T. Gershoff, an associate professor in the department of human development and family sciences at University of Texas at Austin, said the study adds to a growing body of research showing negative effects of spanking.

"Almost all studies point to the negative effects of spanking," Gershoff said. "It makes kids more aggressive, more likely to be delinquent, and more likely to have mental health problems. The more kids are spanked, the more they are likely to be physically abused by their parents. This does not mean everyone who spanks physically abuses, but that risk is there."

Because children tend to mimic parental behaviors, it's possible spanking "creates a model for using physical aggression," Gershoff said. "Spanking is just hitting."

Less is known why spanking could inhibit cognitive development. One possibility is that parents who spank are less likely to use reasoning with their children, something that's good for development, Gershoff said.


DrMomma's Note: When we look at the cognitive functioning of human babies (i.e. those under the age of 36 months), and especially those who are not yet verbal, the brain interprets physical pain and emotional pain in the same way. Both hurt - badly. Aggression against a baby (whether from spanking, leaving a baby in isolation, leaving a baby to cry alone, genital cutting or other sexual abuse, and overall hostility) leads to a spike in cortisol and other stress hormones. When these 'negative' hormones are at an all time high, especially for days on end, it is impossible for the rest of the brain to focus and develop normally.

In addition, while this study neglected to factor in the feeding of babies - whether by breast or artificial feeding means - we know that cortisol spikes happen more often in both babies and mothers when breastfeeding is not a part of the mother-baby relationship. Babies are more likely to be described as 'fussy' and mothers are more likely to be irritated with their infant and/or use physical aggression in handling them. Being held at the breast (especially skin-to-skin) and the act of nursing, keeps hormones in check, releases oxytocin ('the love hormone') and other feel-good endorphins in both mom and baby. In the United States, lack of breastfeeding is correlated with lower socio-economic status, and ethnicity - fewer black mothers nurse their babies than Hispanic or white mothers. This reflects the findings and patterns of spanking in previous studies (sociologically, as breastfeeding decreases, spanking and other physical aggression increases). In addition, neurologically, a lack of human milk leads to lowered cognitive functioning. For all these reasons, it follows that a normal, baby-cued breastfeeding relationship may play a roll in the absence of spanking behavior and a baseline level of cognitive functioning.


Study Citation:

Berlin, Lisa, et. al. "Correlates and Consequences of Spanking and Verbal Punishment for Low-Income White, African American, and Mexican American Toddlers." Child Development. 80:5; 1403-1420.


Related Reading:

Why Love Matters: How Affection Shapes a Baby's Brain [book]

The Science of Parenting: How today's brain research can help you raise healthy, emotionally balanced children [book]

The Continuum Concept: In Search of Happiness Lost [book]

Our Babies, Ourselves [book]

The No Spanking Page alternative ideas to spanking

Why Do We Spank Our Babies?


Infant Pain Impacts Adult Sensitivity

How Spanking Changed My Life

Spanking Decreases Intelligence? 

Project No Spank 

"Terrible Twos?!" Books for Raising Healthy Toddlers


Dr Sears: 10 Reasons Not to Hit Your Child


Healthy Discipline Books and Resource Collection for toddlers and beyond 

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